Aspects of Palynology and Palaeoecology: Festschrift in Honour of Elissaveta Bozilova

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Aspects of Palynology and Palaeoecology

Professor Dr. Sc. Elissaveta Bozilova is one of the outstanding Bulgarian botanists who has been working successfully since the early 1960’s in the field of palynology and palaeoecology. She has published more than 140 scientific papers in national and international journals, symposia proceedings and books, related to Quaternary flora and vegetation history, marinopalynology, aeropalynology, melissopalynology, pollen morphology, pollen monitoring, pollination ecology and archaeobotany. Her most important professional merit is the organization, administration and establishment of the Laboratory of Palynology at the Department of Botany, Sofia University “St. Kliment Ohridski”, as the leading scientific and educational centre in basic and applied palynology in Bulgaria. This jubilee volume comprises papers dealing with various aspects of palynology and inferences drawn from pollen-based research. In particular, new detailed palaeoecological information is provided for selected areas in Europe related to the postglacial vegetation development, climate change, environmental history and human impact. The book will be of use to scientists working in palynology, palaeoecology, palaeogeography, geology, climatology, archaeology and forestry.

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Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova Editor Spassimir Tonkov

Scanning electron micrographs on the cover by Prof. Siwert Nilsson and Dr. Dolja Pavlova.

ISBN 954-642-179-0

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Contents

ASPECTS OF PALYNOLOGY AND PALAEOECOLOGY Festschrift in honour of Elissaveta Bozilova Editor Spassimir Tonkov

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Spassimir Tonkov and Lyubomir Penev

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Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova

Editor Spassimir Tonkov

Sofia-Moscow 2003

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Spassimir Tonkov and Lyubomir Penev ASPECTS OF PALYNOLOGY AND PALAEOECOLOGY Festschrift in honour of Elissaveta Bozilova

Edited by Spassimir Tonkov

First published 2003 ISBN 954-642-179-0

© PENSOFT Publishers All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the copyright owner. Pensoft Publishers, Acad. G. Bonchev Str., Bl.6, 1113 Sofia, Bulgaria Fax: +359-2-870-45-08, e-mail: [email protected], www.pensoft.net Printed in Bulgaria, May 2003

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Table of contents Preface ............................................................................................................................................... 7 Spassimir Tonkov and Lyubomir Penev Elissaveta Bozilova – an appreciation .................................................................................... 9 Gerhard Lang Immigration of Tilia in Europe since the last Glacial ...................................................... 21 Sheila Hicks Towards better temporal, spatial and ecological resolution in palaeoecological reconstructions: the role of pollen monitoring ................................................................. 43 Juliana Atanassova, Lars-König Königsson† and Sheila Hicks Late Holocene vegetation development on the island of Fåro, Gotland, Sweden ..... 61 Carl-Adam Hæggström and Eeva Hæggström Can natural habitats be utilised in a sustainable way? ....................................................... 81 Tiiu Koff and Mihkel Kangur Vegetation history in Northern Estonia during the Holocene based on pollen diagrams from a small kettlehole and lake sediments ....................................................................... 113 Herbert E. Wright, Jr., Brigitta Ammann, Ivanka Stefanova, Juliana Atanassova, Nino Margalitadze, Lucia Wick and Tatiana Blyakharchuk Late-glacial and Early-Holocene dry climates from the Balkan peninsula to Southern Siberia ........................................................................................................................................ 127 Guy Jalut, Antoniu Bodnariuc, Anne Bouchette, Jean-Jacques Dedoubat, Thierry Otto and Michel Fontugne Holocene vegetation and human impact in the Apuseni Mountains, Central Romania .. 137 André Lotter and Gabriele Hofmann The development of the late-glacial and Holocene diatom flora in Lake Sedmo Rilsko (Rila Mountains, Bulgaria) .................................................................................................... 171

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Table Spassimir of contents Tonkov and Lyubomir Penev

Nikolaos Athanasiadis, Achilles Gerasimidis and Sampson Panajotidis A palynological study in the Beles Mountains, Northern Greece ................................ 185 Sytze Bottema, Katerina Kopaka and Apostolos Alexopoulos The Late-Holocene vegetation history of Gavdos (Crete) in relation to long-distance pollen dispersal: the Trypiti pollen diagram ...................................................................... 199 Mariana Filipova-Marinova Postglacial vegetation dynamics in the coastal part of the Strandza Mountains, Southeastern Bulgaria ............................................................................................................ 213 Spassimir Tonkov A 5000-year pollen record from Osogovo Mountains, Southwestern Bulgaria ........ 233 Maria Lazarova Late Holocene vegetation history of the Central Rhodopes Mountains, Southern Bulgaria .................................................................................................................................................... 245 Elena Marinova The new pollen core Lake Durankulak-3 : a contribution to the vegetation history and human impact in Northeastern Bulgaria ........................................................................... 257 Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria ............................. 269

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Preface This volume was prepared to honour Professor Elissaveta Bozilova on the occasion of her 70th anniversary, and in recognition of her substantial contribution to the development of modern palynological and Quaternary palaeoecological studies in Bulgaria. The book is a compilation of 15 papers by European, North American and Asian palynologists and palaeoecologists with whom Professor Bozilova has kept close scientific contact for many years. One group of papers covers various aspects of palynology and inferences drawn from pollen-based research. The other group deals with palaeocological case studies from selected areas of Europe, starting from the Scandinavian countries in the north, and ending in the south-east, the Balkan peninsula. For this latter area new detailed information related to the postglacial vegetation development, climate change, environmental history and human impact is provided. I would like to thank all the contributors for their willing and positive response with high-quality papers. In the course of preparing this volume I received useful advice from a number of colleagues. Personally, I am indebted to Dr. Sheila Hicks for her invaluable help with both the linguistics and the structural arrangement of the book. The Managing Director of the Pensoft Publishers Dr. Lyubomir Penev kindly provided all the facilities including financial support for the publication. I am grateful to Teodor Georgiev who was responsible for the preprint and the graphical design of the book. Sofia, May 2003

The Editor

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Spassimir Tonkov and Lyubomir Penev

Prof. Dr. Sc. Elissaveta Bozilova

Spassimir Tonkov (ed.) 2003 Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 9-20

© PENSOFT Publishers Sofia - Moscow

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Elissaveta Bozilova – an appreciation Spassimir Tonkov1 and Lyubomir Penev2 Laboratory of Palynology, Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria E-mail: [email protected] 2 Central Laboratory for General Ecology, Bulgarian Academy of Sciences, 2 Gagarin Str., 1113 Sofia, Bulgaria. E-mail: [email protected] 1

Academic Biography Elissaveta Bozilova was born on 17th March 1932 in Sofia. She was educated at Sofia University “St. Kliment Ohridski”, Faculty of Biology-Geology-Geography, Department of Botany (1951-1956). There, her interest in botany, and subsequently in palynology, was encouraged by Prof. Boris Kitanov. As a diploma student under his supervision she carried out a geobotanical investigation on the Vitosha Mountains near Sofia. Later, shortly after the successful completion of her studies, she joined the academic staff as an assistant in the Department of Botany (1958). The following years were an intensive period in Elissaveta Bozilova’s remarkable career, during which she combined both teaching and research activities in the broad field of palynology. She was fascinated at first by the pollen morphology of gymnosperm and flowering plant taxa but she soon realized the importance of the application of this knowledge to the investigation of the Bulgarian flora and vegetation history. Her Ph. D. thesis (1972) entitled Lateglacial and Postglacial History of Vegetation in Rila Mountains became a turning point in the establishment of modern palaeoecological studies in Bulgaria. In this thesis, based on the pollen analysis of peat deposits supplemented with radiocarbon dates, she postulated for the first time the main stages and characteristic features of the postglacial vegetation development (tree migrations, fluctuations in the timber-line, the formation of vegetation belts, pollen dispersal mechanisms and human impact) in the highest mountain area of the Balkans that has been glaciated during the Quaternary. Subsequently, such investigations were extended to other mountain areas of southwestern Bulgaria, the Pirin Mountains in particular. By the end of 1970’s, as a Docent in Botany, she was already a well-trained researcher who had, by invitation, visited the famous palynological centers in Krakow, Moscow, Göttingen and Amsterdam in order to participate in professional training and joint research with Magdalena Ralska-Jasiewiczowa, Hans-Jürgen Beug, and Anton Smit. These visits laid the foundation for long-lasting years of fruitful scientific and personal contact.

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One of the most important professional merits of Elissaveta Bozilova was the organization of the Laboratory of Palynology at the Department of Botany, which she administrated for more than two decades until 2000. Within a short period of time the laboratory established itself as a leading centre in basic and applied palynology, and the staff started enthusiastically to work on a wide range of scientific issues related to floral and vegetation history, pollen morphology, marinopalynology, aeropalynology, archaeobotany, melissopalynology and pollination ecology. Apart from her teaching activities at the Department of Botany giving student courses on Vascular Plant Systematics, Plant Geography, Plant Resources, Quaternary Palynology and Palaeoecology, Elissaveta Bozilova supervised a number of graduate research students, registered for the degrees of M.Sc. and Ph.D. Today, the majority of her students have gone on to develop research and teaching in the wide field of botanical science in universities, institutes, laboratories and museums. At an early stage Elissaveta Bozilova realized the great importance of multidisciplinary collaboration in Quaternary studies. In recognition of her research achievements she was invited to organize the Bulgarian palynological community that joined the IGCP Project 158B Palaeohydrological Changes in the Temperate Zone During the Last 15000 Years - Lake and Mire Environments led by Björn Berglund. In conjunction with this project, Elissaveta Bozilova devoted most of her time to introducing the new uniform approach to palaeoecological investigations of Late Quaternary deposits in Bulgaria. By that time the door to the most recent methodological and technical achievements in European palaeoecology and palynology was wide opened to Bulgarian scientists. Their intensive work during the period 1980-1988, coordinated efficiently by Elissaveta Bozilova, resulted in the establishment of a national set of standardised reference sites (lakes and mires), providing valuable high-resolution information on the past environmental changes in both the lowlands and the montane areas of Bulgaria. This information was synthesized in a separate chapter of the monograph Palaeoecological Events During the Last 15000 Years. Regional Syntheses of Palaeoecological Studies of Lakes and Mires in Europe (1996). It is important to point out that upon Elissaveta Bozilova’s invitation a number of outstanding palynologists and palaeoecologists, among them Hans-Jürgen Beug, Björn Berglund, Gerhard Lang, John Birks, Yrjö Vasari, Lars-König Königsson, Herbert Wright, Brigitta Ammann, Sheila Hicks and many others, visited Bulgaria to share gratuitously their knowledge and experience in palaeoecological research, both in the field and in the laboratory. Stimulated by such impulses, the Bulgarian palynological community organized two international symposia (1985, 1993) related to the most recent achievements in Holocene palaeoecology in Bulgaria and adjacent areas. Elissaveta Bozilova’s own research studies culminated in the presentation of her Dr. Sc. thesis (1986) entitled Palaeoecological Conditions and Vegetation Changes in Eastern and Southwestern Bulgaria During the Last 15000 Years for which she received numerous tokens of recognition from abroad and in her own country, by no means the least of which was a professorship (1988) at the Department of Botany. This brilliant work summarized her profound palaeoecological results and knowledge on the late-glacial and Holocene flora, vegetation history and climate change, based on analyses of coastal lake and Black Sea marine sediments, montane peat bogs and also lakes. An important part of this thesis is her interpretation of the thousand of years of

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human impact on the natural environment during prehistoric times and her unraveling of landuse history in connection with human occupation and economy. Through this she demonstrated her many years of fruitful contacts with Bulgarian archaeologists. During 1990s, as a member of the Advisory Board for two successive mandates, Elissaveta Bozilova participated actively in the organization and launching of the European Pollen Database, the then new initiative of the international palynological community, aimed at archiving palaeoecological information collected from all over Europe and utilising modern information technology to address specific research questions. The experience and respect that Elissaveta Boziolva has gathered in contacting and organizing scientists helped her to play an active role in the current international research project Pollen Monitoring Programme led by Sheila Hicks. It is remarkable that whilst successfully completing the many and varied teaching and administrative duties at the university, as well as participating in scientific and expertise councils, Elissaveta Bozilova maintained and continued her productive involvement in research projects through active field work and the publication of results. For many years she was, and still is, the Editor-in-Chief of the Annual of Sofia University-Botany Volume, one of the oldest botanical periodicals in Bulgaria. Since 1971 she has been invited to attend many international congresses, symposia, conferences and meetings in almost all European countries, Asia and Africa. Her retirement three years ago was only symbolic. As a highly dedicated and erudite person she has continued teaching in the department, thus helping younger colleagues and sharing her vast knowledge. With respect to research, a dozen notable new publications in international and national journals have appeared, focused mainly on the realization of her long-held idea to study sediments from the glacial lakes in the Rila and Pirin Mouintains. Elisaveta Bozilova’s endless enthusiasm and active position in modern science is a logical answer to the present-day challenges in the field of palynology and palaeoecology at the onset of the new millenium. We all, her friends and colleagues both within Bulgaria and from abroad, with whom she has worked and continues to work, have felt that a more public tribute should be made to the woman and professor who has contributed so much to the development of modern palynology in Bulgaria, both as a teacher and as an outstanding research worker. This tribute is now presented as a special volume and dedicated to her at her 70th anniversary jubilee in appreciation of her merits and achievements. Research students of Prof. Elissaveta Bozilova, registered for the degree of Ph.D. Rayna Yankova (1980) Aeropalynological studies of some sites in Bulgaria in relation to pollen allergy Olga Petkova (1984) Palynological study of honey and pollen from the Smolyan and Beden regions Spassimir Tonkov (1985) Palynological study of the vegetation changes during the last 8000 years in several mountains in southwestern Bulgaria Mariana Filipova (1986) Pollen-analytical investigations of Lake Shabla - Ezeretz and the northern Bulgarian Black Sea shelf

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Juliana Atanassova (1990) Late Quaternary vegetation development based on data from sporepollen analysis of sediments from the western sector of the Black Sea Ivanka Stefanova (1991) Palaeoecological investigation of peat-bogs and lakes in the northern Pirin Mountains Hristina Panovska (1993) Palaeoecological investigations in some mountains in southwestern Bulgaria Maria Lazarova (1994) Pollen-analytical investigation of Holocene sediments from the Danubian lakes Srebarna and Garvan

Bibliography of publications by Prof. Elissaveta Bozilova to 2002 Bozilova, E. 1963. Pollen morphology of bulgarian species from g. Pinus L. Annual of Sofia University, Faculty of Biology, Geology and Geography, LVI, 1, 119-141 (In Bulgarian with French summary). Bozilova, E., E. Petrova. 1964a. Pollen morphology of bulgarian species from g. Carpinus L. and g. Ostrya Mill. Annual of Sofia University, , Faculty of Biology, Geology and Geography, LVII, 1, 50-63 (In Bulgarian with French summary). Bozilova, E., E. Petrova. 1964b. Palynological study on two species from g. Geum L. in the bulgarian flora. Annual of Sofia University, Faculty of Biology, Geology and Geography, LVII, 1, 119-141 (In Bulgarian with French summary). Bozilova, E. 1966. Pollen morphology of bulgarian species from g. Fraxinus L. Annual of Sofia University, Faculty of Biology, 59, 2, 85-92 (In Bulgarian with French summary). Bozilova, E., A. Petrova. 1967a. On the pollen of some species of the g. Viola L. Comptes rendues de l’Academie bulgare des Sciences, 20 (9), 943-945. Bozilova, E., A. Petrova. 1967b. Morphology of the pollen grains of bulgarian species from g. Minuartia L. Annual of Sofia University, Faculty of Biology, 60, 2, 57-74 (In Bulgarian with English summary). Bozilova, E., M. Anchev. 1969. Pollen analysis of honey from the Kjustendil-Znepole floristic region. Annual of Sofia University, Faculty of Biology, 62, 2, 12-29 (In Bulgarian with English summary). Bozilova, E., R. Yankova. 1969a. On the pollen of some species from g. Astragalus L. in Bulgaria. Annual of Sofia University, Faculty of Biology, 61, 2, 2-11 (In Bulgarian with English summary). Bozilova, E., R. Yankova. 1969b. Aeropalynology. Biology and Chemistry, XII, 5, 5-7 (In Bulgarian). Bozilova, E., R. Yankova. 1971. A study on the pollen content in the air of town Varna and the resorts of Druzba and Zlatni Pjasaci during 1969. Annual of Sofia University, Faculty of Biology, 63, 2, 75-84 (In Bulgarian with English summary). Bozilova, E. 1972. Lateglacial and Postglacial History of Vegetation in Rila Mountains. Ph.D. Thesis. Sofia University “St. Kl. Ohridski” (In Bulgarian). Bozilova, E. 1972. Pollen-analytical studies in the high-mountain belt of the north-eastern part of Rila Mountains. Annual of Sofia University, Faculty of Biology, 64, 2, 19-28 (In Bulgarian with English summary). Bozilova, E., L. Evstatieva. 1972. Pollen analysis of Paleolithic deposits in the cave Svinskata Dupka (Western Stara Planina Mountains, Lakatnik). Annual of Sofia University, Faculty of Biology, 64, 2, 30-36 (In Bulgarian with English summary). Bozilova, E. 1973a. Notes on the pollen grains of Lepidotrichum Vel. et Bornm. and its related genera. Comptes rendues de l’Academie bulgare des Sciences, 26 (11), 1521-1523.

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Bozilova, E. 1973b. Pollen analysis of a peat-bog from NW Rila Mountains in Bulgaria. In: Proceedings III-rd International Palynological Conference Moscow, 44-46. Bineva, I., E. Bozilova, V. Vulchev, R. Yankova. 1973. Chemical characteristics of the pollen grains of certain species of maple growing in Bulgaria. Comptes rendues de l’Academie bulgare des Sciences, 26 (8), 1053-1055. Bozilova, E., R. Yankova. 1974. Survey of airborne pollen in Varna and resorts “Zlatni Pjasaci” and “Druzba” during 1970-1972). Annual of Sofia University, Faculty of Biology, 66, 2, 19-24. Jankova, R., E. Bozilova. 1974. Pollen calendars for Bulgaria. In: Atlas Europeen des pollens allergisants (J. Charpin, R. Surinyach eds.). Sandoz Edition, 104-107. Bozilova, E. 1975a. Pollenanalytical investigations in Northeastern Pirin Mountains. Annual of Sofia University, Faculty of Biology, 69, 2, 20-25. Bozilova, E. 1975b. Changes of vegetational belts in Rila Mountains during Late- and postglacial time. Biuletyn Geologiczny, 19, 93-99. Bozilova, E. 1975c. Correlation of the vegetational development and climatic changes in the Rila and Pirin Mountains during the Lateglacial and postglacial time compared to other areas. In: Problems of Balkan Flora and Vegetation (D. Jordanov ed.). Publ. House of Bulg. Acad. Sci., Sofia, 64-71. Bozilova, E., M. Filipova. 1975. Pollen analysis of cultural layers of Lake Varna. Bulletin du Musee National de Varna, XI, 19-25 (In Bulgarian with English summary). Bozilova, E. 1976. Vegetation development in the Rila Mountains in the Lateglacial and postglacial time. Forest Science, XIII, 5, 10-20 (In Bulgarian with English summary). Bozilova, E. , H. Chan. 1976. Pollen and chemical analysis of honey from different regions in Bulgaria. Annual of Sofia University, Faculty of Biology, 67, 2, 15-29 (In Bulgarian with English summary). Bozilova, E., M. Djankova. 1976. Vegetation development during the Eemien in North Black Sea region. Phytology, 4, 25-32. Bozilova, E., R. Yankova. 1976. Electron microscopic studies of some species of g. Jurinea Cass. Comptes rendues de l’Academie bulgare des Sciences, 29 (3), 403-405. Bozilova, E., R. Yankova. 1977. Aeropalynological study of Varna and the resorts “Druzba” and “Zlatni Pjasaci” during 1970-1973. Annual of Sofia University, Faculty of Biology, 68, 2, 45-50 (In Bulgarian with English summary). Bozilova, E. 1977a. Pollenanalytical investigations in Eastern Rila Mountains. Annual of Sofia University, Faculty of Biology, 68, 2, 53-60. Bozilova, E. 1977b. The Late Holocene history of vegetation in Northwestern Pirin Mountains. I. Phytology, 7, 18-24. Bozilova, E., L. Filipovitch, E. Chakalova. 1978. Paleobotany and its application in archaeological studies. Interdisciplinary Research, Archaeological Museum and Institute of Archaeology, II, 58-69 (In Bulgarian with French summary). Yankova, R., B. Petrunov, E. Bozilova. 1978. Distribution of pollen grains in the air of some touristic regions in Bulgaria. International Aerobiology Newsletter, 7, 6-10. Bozilova, E., A. Smit. 1979. Palynology of Lake “Sucho Ezero” from South Rila Mountains (Bulgaria). Phytology, 11, 54-67.

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Bozilova, E., E. Chakalova, L. Filipovitch. 1979. Instructions on methods of application of paleobotany in archaeological studies. Interdisciplinary Research, Archaeological Museum and Institute of Archaeology, III-IV, 63-73 (In Bulgarian with English and French summaries). Bozilova, E., M. Filipova, P. Dimitrov. 1979. Pollen analysis of late Quaternary sediments from the western peripheral shelf area of the Black Sea. Bulletin du Musee National de Varna, XV, 157-161 (In Russian with Bulgarian summary). Spiridonov, H., E. Bozilova. 1979. On the age of the peat sediments in the valley of the Chaira river, Rila Mountains. Problems of Geography, 1, 51-54 (In Bulgarian with English summary). Terziiski, D., E. Bozilova. 1979. Palynological investigation of Ramonda serbica Panc. and Haberlea rhodopensis Friv. Annual of Sofia University, Faculty of Biology, 72/73, 2, 27-32 (In Bulgarian with English summary). Komarov, A., E. Bozilova, M. Filipova, O. Udintseva. 1979. Palynological spectra and their stratigraphical interpretation. In: Geology and Hydrology of the Western Part of the Black Sea (Y. Malovytsky ed.). Bulg. Acad. Sci., Sofia, 85-98 (In Russian). Chakalova, E., E. Bozilova. 1980. Plant remains found at the settelement mount near Dyadovo. Expeditio Thracica 1, 155-162 (In Bulgarian with English summary). Stojanov, S., E. Bozilova. 1980. The application of pollen analysis in criminology for the study of soils. Proceedings Institute of Criminology, IX, 101-105 (In Bulgarian). Yankova, R., E. Bozilova. 1980.The airborne pollen spectra in the Black Sea region and pollen allergy. Annual of Sofia University, Faculty of Biology, 70, 2, 49-62 (In Bulgarian with English summary). Bozilova, E. 1981a. Vegetational and ecological changes in the Parangalitsa Reserve during the last 4000 years. In: Proceedings Regional Symposium Project 8-MAB-UNESCO, Bulg. Acad. Sci., 154-159 (In Bulgarian with English summary). Bozilova, E. 1981b. Changes of vegetation in the Rila Mountains during the last 12000 years. Annual of Sofia University, Faculty of Biology, 71, 2, 38-44 (In Bulgarian with English summary). Bozilova, E., M. Filipova. 1981. The application of pollen analysis in speleological investigations. In: Proceedings European Regional Speleological Conference, 2, 19-20. Chakalova, E., E. Bozilova. 1981. Plant material from the settlemet mound near Rakitovo. Interdisciplinary Research, Archaeological Museum and Institute of Archaeology, VII-VIII, 77-88 (In Bulgarian with English summary). Bozilova, E. 1982. Holocene chronostratigraphy in Bulgaria. Striae, 16, 88-90. Bozilova, E., S. Tonkov. 1983. Glacial refugia and migration routes of Picea abies (L.) Karst. and Abies alba Mill. on the territory of Bugaria during the last 15000 years. In: Proceedings III-rd National Botanical Conference, Bulg. Acad. Sci., 684-691 (in Bulgarian with English summary). Filipova, M. E. Bozilova, P. Dimitrov. 1983. Palynological and stratigraphical data from the southern part of the Black Sea shelf. Oceanology, 11, 24-33. Stoilov, K., E. Bozilova, N. Popov, T. Nenov. 1983. The XIth INQUA Congress. Problems of Geography, 2, 77-80 (In Bulgarian). Bozilova, E., S. Tonkov. 1984a. In: The Red Data Book of PR of Bulgaria (V. Velchev ed.). Vol. 1. Plants (21 articles) (In Bulgarian).

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Bozilova, E., S. Tonkov. 1984b. Palynological evidence for the developemnt of vegetation in Bulgaria during the last 50000 years. Annual of Sofia University, Faculty of Biology, 74, 2, 77-83. Chakalova, E., E. Bozilova. 1984. Plant remains from the Early Bronze Age. Annual of Sofia University, Faculty of Biology, 74, 2, 18-27 (In Bulgarian with German summary). Tonkov, S., E. Bozilova. 1984. Vegetation development in the mountainous areas of southwestern Bulgaria. Correlation of available palynological data. In: Pre-report of the joint meeting IGCP Project A+B, Marseilles, 100-107. Bozilova, E. 1985a. Palaeoecology and its application in Bulgaria. In: Proceedings National Biological Conference (Section Ecology), 17-21. Bozilova, E. 1985b. Palynological research on Lateglacial and Holocene sediments in Bulgaria. INQUA Newsletter 11, 7-9. Bozilova, E. 1985c. Excursion Guide. Palaeoecology and Palaeohydrology of the Balkan Peninsula and Adjacent Areas (S. Tonkov et al. eds.). Symposium Varna, Univ. Sofia Press, 10-12, 19-21, 25-28, 33-36. Bozilova, E., I. Ivanov. 1985. Ecological conditions in the area of Lake Varna during the Eneolithic and Bronze Age according to palynological, palaeoethnobotanical and archaeological data. Bulletun du Musee National de Varna, XXI, 43-50 (In Bulgarian with English summary). Bozilova, E., S. Tonkov. 1985a. Radiocarbon dating and pollen-analytical investigations of peat bogs in the mountainous areas of Bulgaria. Annual of Sofia University, Faculty of Biology, 75, 2, 8387 (In Bulgarian with English summary). Bozilova, E., S. Tonkov. 1985b. Migration routes of some deciduous trees in Bulgaria during Lateglacial and postglacial periods. Annual of Sofia University, Faculty of Biology, 75, 2, 88-95. Bozilova, E.,S. Tonkov. 1985c. Vegetational development in the mountainous areas of southwestern Bulgaria. I. Palynological investigations and reconstruction of past vegetation. Ecologia Mediterranea, XI (1), 33-39. Bozilova, E., S. Tonkov. 1985d. Palaeoecological studies in Lake Durankulak. Annual of Sofia University, Faculty of Biology, 76, 2, 25-30. Bozilova, E. 1986a. Palynological investigations and reconstruction of the past ecological conditions in Bulgaria. In: Proceedings XXXII-nd National Archaeological Conference, Bulg. Acad. Sci., 290291 (In Bulgarian). Bozilova, E. 1986b. Palaeoecological Conditions and Vegetation Changes in Eastern and Southwestern Bulgaria During the Last 15000 years. Dr. Sc. Thesis, Sofia University “St. Kl. Ohridski” (In Bulgarian). Bozilova, E. 1986c. List of type regions, reference sites and active scientists-Bulgaria. In: Project catalogue for Europe IGCP Project 158B (M. Ralska-Jasiewiczowa ed.). LUNBDS, 11-18. Bozilova, E., M. Filipova. 1986. Palaeoecological environment in northeastern Black Sea area during Neolithic, Eneolithic and Bronze periods. Studia Praehistorica, 8, 160-166. Bozilova, E., S. Tonkov. 1987a. Lake sediments as indicators of biotic and abiotic changes. In: Proceedings I-st National Conference of Biological Monitoring, Bulg. Acad. Sci., 16-19 (In Bulgarian with English summary). Bozilova, E., S. Tonkov. 1987b. Palaeoecological investigations of lakes in Bulgaria. In: Proceedings Symposium “The Preservation of the Genefund in Wetland Areas”, Bulg. Acad. Sci., 10-16.

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Lazarova, M., K. Strashevska, E. Bozilova. 1987. Geomorphological characteristics and vegetation development of Lake Srebarna during the Holocene. In: Proceedings Symposium “The Preservation of the Genefund in Wetland Areas”, Bulg. Acad. Sci., 74-80 (In Russian). Bozilova, E., M. Filipova. 1988. The vegetation development during the Holocene along the bulgarian Black Sea coast. In: Proceedings X-th Dendrological Congress, Bulg. Acad. Sci., 154-159 (In Russian with English summary). Bozilova, E., S. Tonkov. 1988. Palynological data on the history of the flooded forests in Bulgaria. In: Proceedings X-th Dendrological Congress, Bulg. Acad. Sci., 149-153 (In Russian with English summary). Tonkov, S., E. Bozilova. 1988. The postglacial distribution of fir in southwestern Bulgaria. In: Proceedings X-th Dendrological Congress, Bulg. Acad. Sci., 338-342 (In Russian with English summary). Bozilova, E., J. Atanassova. 1989. Palaeoecological conditions and vegetation history in the area of Lake Durankulak. In: Durankulak 1 (H. Todorova ed.). Bulg. Acad. Sci., 197-202 (In Bulgarian). Bozilova, E., M. Lazarova, K. Strashevska. 1989. Geomorphological characteristics and development of the vegetation in the region of Lake Srebarna. Annual of Sofia University, Faculty of Biology, 79, 2, 99-109 (In Russian with English summary). Bozilova, E., E. Chakalova, K. Kossev, S. Tonkov. 1989. Palaeoethnobotanical materials from caves in the West Rhodopes. Geographica Rhodopica, vol. 1, Kliment Ohridski Univ. Press, Sofia, 182-185. Bozilova, E., H. Panovska, S. Tonkov. 1989. Pollenanalytical investigations in the Kupena National reserve, West Rhodopes. Geographica Rhodopica, vol. 1, Kliment Ohridski Univ. Press, Sofia, 186-190. Bozilova, E., V. Velev, V. Kalcheva, P. Nozharov, R. Stojanova. 1989. Quaternary sediments in the profile C3 from the northern shelf of Bulgaria. Comptes rendues de l’Academie bulgare des Sciences, 31, 1167-1170 (In Russian with English summary). Filipova, M., E. Bozilova, P. Dimitrov. 1989. Palynological investigation of the Late Quaternary deepwater sediments from the southwestern part of the Black Sea. Bulletin du Musee National de Varna, 25 (40), 177-186. Bozilova, E., M. Filipova-Marinova. 1990. Surface samples from the northern Bulgarian coastal region. Annual of Sofia University, Faculty of Biology, 80, 2, 26-40 (In Bulgarian with English summary). Bozilova, E.,S. Tonkov. 1990. The impact of Man on the natural vegetation in Bulgaria from the Neolithic to the Middle Age. In: Man’s Role in the Shaping of the Eastern Mediterranean Landscape (S. Bottema et al. eds.). Balkema, Rotterdam, 327-332. Bozilova, E., S. Tonkov, D. Pavlova. 1990. Pollen and plant macrofossil analyses of Lake Sucho Ezero in South Rila Mountains. Annual of Sofia University, Faculty of Biology, 80, 2, 48-57. Filipova-Marinova, M., E. Bozilova. 1990. Palaeoecological investigation of Lake Shabla-Ezeretz on the bulgarian Black Sea coast. In: Geological evolution of the western part of the Black Sea in NeogenQuaternary (T. Krastev ed.). Bulg. Acad. Sci., 41-87 (In Russian). Filipova-Marinova, M., E. Bozilova, T. Krastev. 1990. Palynological investigation of Quaternary sediments of core C-1 from the deep part of the Black Sea. In: Geological evolution of the western part of the Black Sea in Neogen-Quaternary (T. Krastev ed.). Bulg. Acad. Sci., 466-494 (In Russian). Panovska, H., E. Bozilova, S. Tonkov. 1990a. Late Holocene vegetation history in the western part of Belasitza Mountains. Geographica Rhodopica 2, Aristotle Univ. Press, Thessaloniki, 1-7.

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Panovska, H., E. Bozilova, S. Tonkov. 1990b. Environmental changes in late Holocene and vegetation developoment in the region of National Reserve Kastraklii (Rhodopa Mts.). Geographica Rhodopica 2, Aristotle Univ. Press, Thessaloniki, 8-12. Krastev, T., E. Bozilova, M. Filipova, R. Stojanova. 1990. Biostratigraphical and palaeoecological data for the Quaternary of the northern Bulgarian Black Sea shelf. Bulletin du Musee National de Varna, 26 (41), 259-272. Atanassova, J., M. Filipova-Marinova, V. Shopov, E. Bozilova. 1990. Pollen analysis in the biostratigraphy of Quaternary sediments from the western sector of the Black Sea. In: Microfossils in bulgarian stratigraphy (T. Nikolov ed.). Bulg. Geol. Soc., 109-115 (In Russian with English summary). Bozilova, E., M. Filipova. 1991. Palynological and palaeoethnobotanical evidence about the human impact on the vegetation along the bulgarian Black Sea coast from the Neolithic till the Greek colonization. In: Proceedings International Symposium Thracia Pontica IV (M. Lazarov et al. eds.). Sofia, 87-96. Bozilova, E., H.-J. Beug. 1992. On the Holocene history of vegetation in SE Bulgaria (Lake Arkutino, Ropotamo region). Vegetation History and Archaeobotany, 1, 19-32. Bozilova, E., M. Filipova, J. Atanassova. 1992. Marinopalynological data about the palaeoecological conditions and vegetation history of Eastern Bulgaria during the last 15000 years. Annual of Sofia University, Faculty of Biology, 82, 2, 79-88 (In Bulgarian with English summary). Atanassova, J., E. Bozilova. 1992. Palynological investigation of marine sediments from the western sector of the Black Sea. Proceedings Institute of Oceanology, 1, 97-103. Popova, Ts., E. Bozilova. 1992. The role of the Balkan peninsula as a linkage between Asia Minor and Middle Europe in the spreading of early agriculture. Annual of Sofia University, Faculty of Biology, 83, 2, 17-26. Stefanova, I., E. Bozilova. 1992. Model of palynological investigation with application of correction factors from the Northeastern Pirin Mountains. Annual of Sofia University, Faculty of Biology, 81, 2, 31-42 (In Bulgarian with English summary). Tonkov, S., E. Bozilova. 1992a. Palaeoecological investigation of Tschokljovo marsh (Konjavska Mountains). Annual of Sofia University, Faculty of Biology, 83, 2, 5-16. Tonkov, S., E. Bozilova. 1992b. Pollen analysis of peat bog in Maleshevska Mountains (Southwestern Bulgaria). Annual of Sofia University, Faculty of Biology, 81, 2, 11-20. Shopov, V., E. Bozilova, J. Atanassova. 1992. Biostratigraphy and radiocarbon data of Upper Quaternary sediments from western part of Black Sea. Geologica Balcanica, 22, 2, 59-70. Huttunen, A., R.-L. Huttunen, Y. Vasari, H. Panovska, E. Bozilova. 1992. Late Glacial and Holocene history of flora and vegetation in Western Rhodopes Mountains, Bulgaria. Acta Botanica Fennica, 144, 63-80. Bozilova, E., M. Filipova. 1993. The anthropogenic influence on the environment along the bulgarian Black Sea coast from the Neolithic till the Middle Ages. In: Proceedings III-rd International Conference “Ecology, economics and environment of the Black Sea region” (P. Stanev ed.). Varna, 149-157 (In Bulgarian). Bozilova, E. 1994. Site Data. Main area: Bulgaria. Palaeoclimate Research 12 (B. Frenzel ed.), Gustav Fischer Verlag, Stuttgart, 114-116. Bozilova, E., H.-J. Beug. 1994. Studies on the vegetation history of the Lake Varna region, northern Black Sea coastal area of Bulgaria. Vegetation History and Archaeobotany, 3, 143-154.

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Bozilova, E. , M. Filipova-Marinova. 1994. Palaeoecological conditions in the area of the prehistoric settlement of Urdoviza near Kiten. In: Proceedings International Symposium Thracia Pontica V (M. Lazarov, H. Angelova eds.). Sozopol, 39-50. Bozilova, E., S. Tonkov. 1994a. The postgalcial distribution patterns of Abies in Bulgaria. Dissertaciones Botanicae, 234, 215-223. Bozilova, E., S. Tonkov. 1994b. Lake sediments in Bulgaria - palaeoenvironmental records. PACT, Belgium, 41, 141-148. Bozilova, E., S. Tonkov, Ts. Popova. 1994. Forest clearance, land use and human occupation during the Roman colonization in Bulgaria. Palaeoclimate Research 10 (B. Frenzel ed.). Gustav Fischer Verlag, Stuttgart, 37-44. Atanassova, J., E. Bozilova. 1994. Surface pollen samples from the western sector of the Black Sea. Annual of Sofia University, Faculty of Biology, 84, 2, 53-70 (In Bulgarian with English summary). Panovska, H., E. Bozilova. 1994. Pollen-analytical investigations of three peat-bogs in Western Rhodopes Mountains (Southern Bulgaria). Annual of Sofia University, Faculty of Biology, 85, 2, 69-86. Filipova, M., E. Bozilova, S. Tonkov. 1994. Palynology of submerged archaeological sites along the bulgarian Black Sea coast. PACT, Belgium, 47, 43-51. Pavlova, D., E. Bozilova, S. Tatzreiter, J. Berge. 1994. Pollen morphology of the bulgarian species from g. Astragalus L.. (Fabaceae) - subgenera Hypoglottis Bge., Phaca (L.) Bge., Astragalus, Cercidothrix Bge., Calycocystis Bge. Annual of Sofia University, Faculty of Biology, 86, 2, 5-28. Bozilova, E. 1995. The upper forest limit in the Rila Mts. in postglacial time - palaeoecological evidence from pollen analysis, macrofossil plant remains and 14C dating. In: Advances in Holocene Palaeoecology in Bulgaria (E. Bozilova, S. Tonkov eds.), Pensoft Publ., Sofia-Moscow, 1-8. Filipova, M., E. Bozilova. 1995. The human impact in the southern coastal bulgarian Black Sea area during the Eneolithic and Early Bronze epoch. In: Proceedings IV-th International Conference “Ecology, economics and environment of the Black Sea region” (I. Slavov ed.). Varna, 97-103 (In Bulgarian). Stefanova, I., E. Bozilova. 1995. Studies on the Holocene history of vegetation in the Northern Pirin Mts. (Southwestern Bulgaria). In: Advances in Holocene Palaeoecology in Bulgaria (E. Bozilova, S. Tonkov eds.), Pensoft Publ., Sofia-Moscow, 9-31. Tonkov, S., E. Bozilova. 1995. Palaeoecological data about the end of the Holocene climatic optimum in Bulgaria – IV millenium BC. Annual of Sofia University, Faculty of Biology, 87, 2, 5-16. Kozuharova, E., E. Bozilova, K. Nanev. 1995. Notes on the pollen morphology of Gentiana lutea L. and G. punctata L. (Gentianaceae). Annual of Sofia University, Faculty of Biology, 88, 2, 29-34. Panovska, H., E. Bozilova, S. Tonkov. 1995. A palaeoecological investigation on the vegetation history in the Southern Pirin Mts. (Southwestern Bulgaria). In: Advances in Holocene Palaeoecology in Bulgaria (E. Bozilova, S. Tonkov eds.), Pensoft Publ., Sofia-Moscow, 32-46. Pavlova, D., E. Bozilova, J. Berge, A. Tutekova. 1995. Pollen morphology of the bulgarian species from g. Astragalus L. (Fabaceae). II – subgenera Trimenianeus Bge., Epiglottis (Bge.) Willk. and Calycophysa Bge. Annual of Sofia University, Faculty of Biology, 87, 2, 29-46. Bozilova, E. 1996. Bulgaria. In: Palaeoecological Events During the Last 15000 Years (B. E. Berglund et al. eds.). Wiley, Chichester, 701-715, 719-721, 726-728.

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Bozilova, E., J. Atanassova, M. Filipova-Marinova. 1997. Marinopalynological and archaeological evidence for the Lateglacial and Holocene vegetation in Eastern Bulgaria. Annual of Sofia University, Faculty of Biology, 89, 2, 69-82. Lazarova, M., E. Bozilova. 1997. The Late Holocene history of flora and vegetation in Northeastern Bulgaria (Mire Garvan, Silistra region). Phytologia Balcanica, 3/1, 3-14. Bozilova, E., S. Tonkov. 1998. Towards the vegetation and settlement history of the southern Dobrudza coastal region, northeastern Bulgaria: a pollen diagram from Lake Durankulak. Vegetation History and Archaeobotany, 7, 141-148. Atanassova, J., E. Bozilova. 1998. Marinopalynological evidence for the Late Quaternary vegetation and climatic changes along the Bulgarian Black Sea coast. Progress in Botanical research (Proceedings of the 1-st Balkan Botanical Congress). Kluwer Acad. Publ., 25-28. Popova, Ts., E. Bozilova. 1998. Paleoecological and paleoethnobotanical data from the Bronze Age in Bulgaria. In: The Steps of James Harvey Gaul, vol. 1 (M. Stefanovich et al. eds.). The James Harvey Gaul Foundation, Sofia, 391-398. Hicks, S., E. Bozilova, K. Dambach, R. D.-Schneider, M. Latalowa. 1998. Sampling methodologies for the collection of modern pollen data and related vegetation and environment. Palaeoclimate Research 27 (B. Frenzel ed.). Gustav Fischer Verlag, Stuttgart, 141-144. Tonkov, S., J. Atanassova, E. Bozilova, G. Skog. 1998. A Late Holocene pollen diagram from Lake Suho Ezero, Rila Monastery area (Central Rila Mts., Southwestern Bulgaria). Phytologia Balcanica, 4/3, 31-38. Bozilova, E., S. Tonkov. 2000. Pollen from Lake Sedmo Rilsko reveals southeast European postglacial vegetation in the highest mountain area of the Balkans. New Phytologist, 148, 315-325. Bozilova, E., J. Atanassova, S. Tonkov, H. Panovska. 2000. Palynological investigations of peatbogs in the Western Rhodope Mountains (SW Bulgaria). Geotechnical Scientific Issues, Thessaloniki, 11 (3), 233-247. Lazarova, M., E. Bozilova. 2000. Vegetational and hydrological changes of the Mire Garvan (North Bulgaria) during Late Holocene. Annual of Sofia University, Faculty of Biology, 91, 2, 75-86. Popova, Ts., E. Bozilova. 2000. Ethnobotanical data about the earliest use and distribution of some narcotic substances. In: Medicinal Plants - Solution 2000. Prof. M. Drinov Acad. Publ. House, Sofia, 57-68 (In Bulgarian). Tonkov, S., E. Bozilova, D. Pavlova, E. Kozuharova. 2000. Surface pollen samples from the valley of the Rilska Reka river, Central Rila Mountains (SW Bulgaria). Annual of Sofia University, Faculty of Biology, 91, 2, 63-74. Athanasiadis, N., S. Tonkov, J. Atanassova, E. Bozilova. 2000. Palynological study of Holocene sediments from Lake Doirani in Northern Greece. Journal of Paleolimnology, 24, 3, 331-342. Bozilova, E. 2001. Towards the post-glacial forest development in the Bulgarian Western Rhodopes mountain reconstructed from palaeoecological data. In: Proceedings International Conference “Forest Research: A Challenge For an Integrated European Approach” (K. Radoglou ed.). Forest Research Institute, Thessaloniki, 217-221. Kozuharova, E., E. Bozilova. 2001. Pollen morphology of some Gentiana species (Gentianaceae) presented in the bulgarian flora. Annual of Sofia University, Faculty of Biology, 93, 2, 83-98.

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Lazarova, M., E. Bozilova. 2001a. Studies on the Holocene history of vegetation in the region of lake Srebarna (northeast Bulgaria). Vegetation History and Archaeobotany, 10, 87-95. Lazarova, M., E. Bozilova. 2001b. Pollen and chemical analysis of honey from different floristic regions in Bulgaria. Phytologia Balcanica, 7(1), 101-112. Lazarova, M., E. Bozilova. 2001c. Pollen analysis of bee loads from the region of Smolyan town (the Rhodopi Mts.). Phytologia Balcanica, 7(2), 201-206. Tonkov, S., S. Hicks, E. Bozilova, J. Atanassova. 2001. Pollen monitoring in the Central Rila Mts., Southwestern Bulgaria: case studies from pollen traps and surface samples for the period 19941999. Review of Palaebotany and Palynology, 117, 167-182. E. Bozilova, S. Tonkov. 2002. Paleoecological evidence on the vegetation history and human occupation in the coastal area of Lake Durankulak, Northeastern Bulgaria. In: Durankulak, Band II. Die prähistorischen Graberfelder (H. Todorova ed.). Deutsches Archäologisches Institut-Berlin, Teil 1, 309-312. Bozilova, E., M. Filipova-Marinova, S. Tonkov. 2002. Palaeoecological reconstruction of the environmental and climatic conditions in Eastern Bulgaria during the Pleistocene and Holocene. In: Proceedings International Scientific Conference “In memory of Prof. Dimitar Jaranov”, Varna 2002, 48-53 (In Bulgarian with English summary). Bozilova, E., J. Atanassova, S. Tonkov, I. Stefanova. 2002. Late Holocene vegetation history of the NW Pirin Mts. II. Palaeoecological investigations of peat-bogs in the Begovitsa river valley. Annual of Sofia University, Faculty of Biology, 90, 2, 23-30. Bozilova, E., S. Tonkov, E. Marinova, H. Jungner. 2002. Pollen and plant macrofossil analyses of Late Holocene sediments from Lake Panichishte in Northwestern Rila Mountains. Razprave IV. Razreda SAZU, Ljubljana, XLIII-2, 49-62. Chakalova, E., E. Bozilova. 2002. Palaeoecological and palaeoethnobotanical material from the settlement mound near Rakitovo. In: The Neolithic Settlement near Rakitovo (M. Vaklinova ed.). GalIko Publ., Sofia, 191-201 (In Bulgarian). Filipova-Marinova, M., E. Bozilova. 2002. Palaeoecological conditions in the area of the praehistorical settlement in the bay of Sozopol during the Eneolithic. Phytologia Balcanica, 8 (2), 133-143. Lazarova, M., E. Bozilova. 2002. Pollen and chemical analysis of honey from different floristic regions in Southern Bulgaria. Phytologia Balcanica, 8 (2), 145-164. Filipova- Marinova, M., R. Christova, E. Bozilova. 2002. Palaeoecological conditions in the bulgarian Black Sea zone during the Quaternary. Comptes rendus de l’ Academie bulgare des Sciences, 55, 8, 61-68. Atanassova, J., S. Tonkov, E. Bozilova, M. Filipova. 2002. Palynological investigation of Holocene sediments from Lake Burgass. Annual of Sofia University, Faculty of Biology, 92, 2, 127-138. Tonkov, S., H. Panovska, G. Possnert, E. Bozilova. 2002. The Holocene vegetation history in the Northern Pirin Mountain, southwestern Bulgaria: pollen analysis and radiocarbon dating of core from Lake Ribno Banderishko. The Holocene, 12, 2, 201-210. Tonkov, S., E. Bozilova, D. Dimitrov, J. Atanassova, D. Pavlova. 2002. Surface pollen samples from the North-western Pirin Mountains (South-western Bulgaria). Annual of Sofia University, Faculty of Biology, 90, 2, 11-21.

© PENSOFT Publishers Sofia - Moscow

Spassimir Tonkov (ed.) 2003 Immigration and expansion of Tilia in Europe since theof last Glacial 21 Aspects Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 21-41

Immigration and expansion of Tilia in Europe since the last Glacial Gerhard Lang Friedrich-Ebert-Strasse 70, D-88400 Biberach, Germany E-mail: [email protected]

ABSTRACT A new synopsis is given of the history of Tilia in Europe during the Late-glacial and the Holocene, on a calibrated time-scale and based on a selection of reliable dated pollen diagrams. The Glacial refugial areas of the European species of Tilia were apparently situated on the Balkan peninsula, perhaps also on the Apennine peninsula and at the southern and southeastern borders of the Alps. There is no certain evidence of Glacial survival of Tilia in other areas, neither on the Iberian peninsula, nor along the coasts of the Black Sea, nor in northeastern Russia or western Siberia. At the end of the Late-glacial (11500 cal. years BP) Tilia was present throughout Italy and the major parts of the Balkans. During the first half of the Holocene Tilia migrated to the northwest and north and reached the Baltic Sea and northern Russia around the 60th degree of latitude at about 9000 cal. years BP, i.e. at the end of the Boreal. England, southern Scandinavia, Finland and Russia north of the 60th degree have been invaded mainly between 9000 and 7000 cal. years BP, i.e. during the Early and Middle Atlantic. The migration ended around 6000 cal. years BP. Evaluated migration rates of Tilia range during the first half of the Holocene between 350 and 820 m/year. Mass expansion of Tilia, mainly during the Atlantic, can preferably be observed in the western parts of Central Europe, where T. cordata and T. platyphyllos occur jointly. KEY WORDS: Vegetation history – Tilia – Late-glacial – Holocene – Europe

DEDICATION Within Europe the Balkan peninsula can undoubtedly claim special phytogeographic interest because this region functioned as a Glacial refuge area for many plants, particularly for trees, and as a starting place for the reforestation of the continent after the last Glacial. One of the outstanding scientists in this key region is Elissaveta Bozilova, who has been engaged there in research on vegetation history for many years. She and her co-workers

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have the great merit of having provided Bulgaria with excellent modern palaeoecological studies of high international standard. It is therefore a great pleasure for me to dedicate the following contribution to Elissaveta at the occasion of her 70th anniversary jubilee. INTRODUCTION At present there exists a steadily growing number of new pollen analytical investigations all over Europe which combine progress in palynological methods with reliable dating series, often throwing new light on old problems of vegetation history. An important contribution with an immense collection of regional syntheses was recently published by Berglund et al. (1996), yet without an attempt of a European synthesis. Hence important results are still waiting for comprehensive interpretation. There exist indeed only a few approaches to surveys on a European scale, e.g. Gliemeroth (1995), Huntley and Birks (1983), Huntley (1988), Lang (1994). In the meantime, however, these publications are at least partly no longer up-to-date or they do not cover the total area of Europe, and some are not based on a reliable calibrated chronology. In this paper the genus Tilia is selected as an example of the history of an important European tree. For graphic presentation the procedure used by Lang (1994) is chosen. The

Fig. 1. Chronology and subdivision of the last 20 000 years: Conventional 14C age (in italics), calibrated 14C age and calendar age (after Roberts 1998 and others).

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chronology is based on a calibrated time scale (Fig. 1) available now throughout the last twenty thousand years (Roberts 1998). TAXONOMY AND PRESENT DISTRIBUTION Dependent on the delimitation of species the genus Tilia comprises up to 65 species. In Europe occur five of these, belonging to two sections: The section Anastraea includes T. cordata, T. platyphyllos, T. rubra and T. dasystyla, the section Astrophilyra T. tomentosa (Table 1). Tilia cordata Mill., Small-Leaved Lime, has by far the largest distribution range of all European Tilia species. It covers approximately about 6.5 millions square kilometres and extends from northern Spain, from France and England to southern Fennoscandia and Russia south of the 63th degree of latitude (Fig. 2; see also the maps in Pigott (1991) and Dahl (1998)). The southeastern limit of the main area runs from the Balkan peninsula along the northwestern border of the Black Sea to northeast, ending east of the Urals at the 75th degree of longitude. Separate disjunctive parts outside the main range exist on the Crimea and in the Caucasus region. The range of T. cordata is very similar to that of Acer platanoides, including also a separate occurrence in the Caucasus. Due to relatively late frondescence - 10 to 14 days later than T. platyphyllos - T. cordata is more resistant against late frosts and the species is also relatively resistant against drought, thus showing an ecological behaviour of continental character. T. cordata, as well as T. Table 1. Taxonomy of European Tilia taxa. After von Engler (1909). Sectio Anastraea von Engl. (= Sectio Tilia) Subsectio Trabeculares von Engl. (= Sectio Tilia sensu Wasiljew 1971) Tilia platyphyllos Scop. (T. grandifolia Ehrh. ex W.D.Koch, T. europaea L.p.p.) subsp. platyphyllos subsp. grandifolia (Ehrh.) Vollim subsp. cordifolia (Bess.) C.K.Schneid. subsp. pseudorubra C.K.Schneid. Tilia rubra DC. subsp. rubra subsp. caucasica (Rupr.) von Engl. Tilia dasystyla Stev. Subsectio Reticulares von Engl. (= Sectio Paratilia sensu Wasiljew 1971) Tilia cordata Mill. (T. parvifolia Ehrh.ex Hofmm., T. ulmifolia Scop., T. europaea L.p.p.) Sectio Astrophilyra von Engl. (= Sectio Lindnera) Subsectio Ebarbulatae von Engl. Tilia tomentosa Moench. (T. argentea DC., T. argentea Desf., T. alba Ait.) Hybrids Tilia x vulgaris Hayne (T. platyphyllos x T. cordata; T. x intermedia DC., T. europaea L.p.p.) Tilia x euchlora C.Koch (T. cordata x T. dasystyla)

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platyphyllos, occur rarely in pure stands but mainly mixed with other broad-leaved trees like Acer, Carpinus, Fraxinus, Quercus and Ulmus. Mixed forests with T. cordata are particularly well developed around the Alps in “Főhn” (warm wind) regions with high rainfall (Trepp 1947, see also Ellenberg 1996). In Central Europe T. cordata is a characteristic species of the Carpinion alliance (in the Braun-Blanquet system). Along the northern limit of the area the tree is often incorporated in conifer forests of the boreal zone. Tilia platyphyllos Scop., Broad-Leaved Lime, has a more restricted distribution range compared with T. cordata. It covers an area of approximately 2 millions square kilometres, which is less than a third of the range of Small-Leaved Lime. The area extends mainly over Central and Southern Europe, reaching Northern Germany, Denmark and Southern Sweden only with scattered occurrences (Fig. 3). Whether the occurrences in England have to be regarded as natural or anthropogenous is still under discussion: Meusel et al. 1978 share the latter opinion. The main area touches Poland only in the south and the tree does not transgress the eastern limits of Belorussia and the Ukraine. Hence, with a few exceptions, the species is absent in Russia. Generally, T. platyphyllos prefers middle mountainous areas of Europe and the distribution range shows great similarity to that of Acer pseudoplatanus. Broad-Leaved Lime is sensitive to late frosts and not very resistant against drought. So in contrast to T. cordata the species shows suboceanic character, preferring warm-humid habitats, particularly on calcarious soils. In Central Europe T. platyphyllos is a characteristic

Fig. 2. Present distribution range of Tilia cordata Mill. After Meusel et al. (1978), transferred to the grid of Atlas Florae Europaeae (provisional).

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species of the Tilio-Acerion alliance (in the Braun-Blanquet system). Within its area the species is polymorphous and split up into 3 or 4 subspecies: subsp. grandifolia is restricted to Northern Europe, subsp. cordifolia to Northern, Eastern and Central Europe, subsp. platyphyllos to Central and Southern Europe and subsp. pseudorubra exclusively to Southern Europe. In areas with joint occurrence of T. platyphyllos with T. cordata the two species hybridise very often (T. x vulgaris). Tilia tomentosa Moench., Silver Lime, occurs in Southwestern Europe, mainly in lower mountainous areas and lowlands of the Balkan peninsula, but also in Western Anatolia. The distribution area covers approximately 550 thousand square kilometres (Fig. 4). Silver Lime is tolerant to drought and restricted to areas with warm continental climate, preferring thermophilous deciduous oak forests. The tree is a characteristic species of the Quercetalia pubescentis order (in the Braun-Blanquet system) occurring in quite a number of different forest associations (Horvat et al. 1974). During the last Interglacial (Eemian) the northern limit of T. tomentosa was shifted more to the north than at present, up to the lowlands of Northern Germany, Poland and Russia (see Frenzel 1968; Meusel et al. 1978). Tilia rubra DC., Red Lime, has a disjunctive distribution covering in scattered occurrences the Balkan peninsula (subsp. rubra) and the Crimea, the Caucasus and the northern parts of Anatolia (subsp. caucasica). The whole range extends over approximately 300 thousand square kilometres (Fig. 4). The species is taxonomically close to T. platyphyllos. In the vegetation monograph of Horvat et al. (1974) Red Lime is not mentioned (probably because some

Fig. 3. Present distribution range of Tilia platyphyllos Scop. After Meusel et al. (1978), transferred to the grid of Atlas Florae Europaeae (provisional).

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Fig. 4. Present distribution range of Tilia tomentosa Moench. and Tilia rubra DC. After Meusel et al. (1978), transferred to the grid of Atlas Florae Europaeae (provisional).

authors include T. rubra, as well as T. dasystyla, in T. platyphyllos), whereas Mayer and Aksoy (1986) make reference to the species as a member of North Anatolian deciduous forests. Tilia dasystyla Stev., Caucasian Lime, occurs in the Caucasus region and in northern Iran. IDENTIFICATION OF POLLEN AND MACROFOSSILS By pollen Tilia can easily be identfied down to genus level: The distinctive morphology of the tricolporate pollen grains - with pronounced thick exine and foveolate sculpture - is so characteristic that confusion with similar pollen types seems impossible. The morphological identification down to species level however is rather problematic. Pollen morphological differences between T. cordata and T. platyphyllos, among others particularly in size, have been described by several authors (Andrew 1971; Guggenheim 1975; Christensen and Blackmore 1988; see also Moore et al. 1991). But according to Beug (in Jung et al. 1972) and others there

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is only a statistical probability of maximal 70-80% of reliable species identification. Up to now, only in few pollen-analytical investigations a separation of the two species has been attempted (e.g. Chen 1988; Hahne 1991, 1992; Stalling 1983, 1987). Possible pollen morphological differences between the other european Tilia taxa are not yet known, so in most cases only pollen records on the genus level are available. Pollen grains of Tilia are exceptionally resistant to oxidation. Therefore, in Glacial or Holocene sediments sometimes reworked older pollen grains of Tertiary or Interglacial age are preserved. However these grains are usually corroded and identifiable as “secondary pollen grains”. Tilia as an entomophilous plant has only a moderate pollen production and the dispersal of pollen is low. Thus lime is significantly underrepresented in pollen spectra, between two to four times (Andersen 1970; Faegri and Iversen 1989). Huntley and Birks (1983) interprete pollen spectra with 1% Tilia (of TP) as indicative of sparse local presence, spectra with 510% Tilia as reflecting local presence of abundant trees and spectra with more than 10% Tilia as indicating dominance of the tree in forests. Records of macrofossils of Tilia concern mostly fruits (nuts), rarely also flowers with anthers and bud scales, in which cases reliable identification down to species level is not always possible. Fruits however allow species determination, due to differences in the distinctness of the nut edges and other morphological features (see e.g. drawings in Katz et al. 1965, p.320/321). Because records of Tilia macrofossils in European Late-glacial and Holocene deposits are not very frequent and do not concern all european species (Table 2) they can only little contribute to the knowledge of Tilia history. Most records of species by macrofossils lie within their present ranges (Table 2). Of special interest are records of T. platyphyllos north of its present range, as indicated by records of the hybrid T. platyphyllos x T. cordata (T. x vulgaris) in the Baltic area. Late-glacial or Holocene records of macrofossils of T. tomentosa and T. rubra are apparently not yet known. IMMIGRATION, EXPANSION AND RETREAT AFTER THE LAST GLACIAL The oldest pollen records of Tilia on the continent - regarding the time period of the last 20000 years - are known from the south of the Balkan peninsula (Fig. 5): Two sites, one situated in the lower mountainous region of Greece (1 Ioannina, Bottema 1974) and the other in the Thessalonian lowland (2 Tenaghi Philippon, Wijmstra 1969), give evidence of the presence of Tilia already at the end of the last Pleni-glacial, around 18000 cal. years BP. Late-glacial records of Tilia in the Bulgarian mountains (3 Sucho Ezero, Bozilova 1995), at the southern foothills of the Carpathian mountains (8 Taul Zanogutii, Farcas et al. 1999) and also at lower elevations on the Apennine peninsula (11 Lago di Monticchio, Watts et al. 1996; 12 Lago di Trasimeno, Drescher-Schneider not publ.) indicate also in these regions a probable Glacial survival of Tilia. At the end of the Late-glacial, around 11500 cal. years BP, Tilia was present already at the southern and southeastern border of the Alps (13 Lago di Ganna, Schneider and Tobolski 1985; 14 Sommersüß, Seiwald 1980). Until now no other

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Table 2. Records of Tilia macrofossils (species level) in European Late-glacial and Holocene deposits (selection). Order follows abbreviations of countries. AT = Atlantic, BO = Boreal, DR3 = Younger Dryas, PB = Preboreal, SB = Subboreal; b = bud scales, f = fruits. In brackets: Citations in reviews. Tilia cordata A Laudachmoor/Salzburg, BO/AT, f, Schmidt 1981 Attersee/Salzburg, AT/SB, f, Schmidt 1983 CH Campra/Ticino, BO, f, Müller 1972 (Burga and Perret 1998) D Chorin/Brandenburg, AT/SB, f,b, Hesmer 1935 (Firbas 1949) Elmshorn/Schleswig, AT, f, Kolumbe and Beyle 1942 (Firbas 1949) Seewiese/Meißner, BO/AT, f, Stalling 1983 Moosburg/Federsee, BO, f, Bertsch 1931 (Firbas 1949) Wasenmoos/Allgäu, BO, f, Paul and Ruoff 1932 (Firbas 1949) DK Gammelung Mose/Langeland AT/SB, f, Jessen 1938 (Jensen 1985) Horsø/Jylland, AT/SB, f, Jessen 1927 (Jensen 1985) Maglemose/Sjaslland, AT/SB, f, Jessen 1920 (Jensen 1985) F Frankental/Vosges, AT, f, Firbas et al. 1948 Maxmoor/Vosges, AT/SB, f, Firbas et al. 1948 I Lago di Ganna/Varese, DR3/BO, f, Schneider and Tobolski 1983, 1985 Tilia platyphyllos A Attersee/Salzburg, AT/SB, f, Schmidt 1983 CH Campra/Ticino, PB/BO, f, Müller 1972 (Burga and Perret 1998) Rotsee/Luzern, PB/BO/AT, f (cf), Letter 1988 D Chorin/Brandenburg, AT/SB, f,b, Hesmer 1935 (Firbas 1949) Moosburg/Federsee, BO, f, Bertsch 1931 (Firbas 1949) Haidelmoos/Konstanz, AT, f, Stark 1925 (Firbas 1949) F Rotried/Vosges, AT/SB, f, Firbas et al. 1948 Sewensee/Vosges, AT/SB, f, Firbas et al. 1948; Schloss 1979 UK Shustoke/Warwickshire, AT/SB, f, Kelly and Osborne 1965 (Godwin 1975) Shippea Hill/Cambridgeshire, AT/SB, f, Clark and Godwin 1962 (Godwin 1975) Tilia x vulgaris (T. platyphyllos x T. cordata) D Kieler Förde, AT, f, Weber 1905 (Firbas 1949) DK Kongsted Lyng/Sjaelland, AT?, f, Milthers 1908 (Jensen 1985)

Glacial survival areas of Tilia (in Europe) have been reliably identified, neither on the Iberian peninsula, nor along the coasts of the Black Sea, nor in the northeast of Russia. At a site north of Moscow (73 Polovetsko-Kupanskoye mire, Khotinskiy 1984) pollen grains of Tilia have been recorded of Allerød and Younger Dryas age, but only as discontinuous occurring single grains. As long as this record is geographically isolated and not corroborated by records at other sites in the region, the interpretation of “secondary pollen” seems to be a more reasonable assumption.

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Fig. 5. Late-glacial and Holocene immigration of Tilia in Europe. Calibrated 14C dates (in kilo years BP) of selected sites (small numbers refer to the reference table in the appendix). Presentation is based on the grid of the Atlas Florae Europaeae. Dotted area shows present distribution of Tilia.

The Holocene immigration of Tilia into the western, northwestern and northern parts of Europe started from the Alps and the Carpathian Mountains (Fig. 5). At the end of the Preboreal, around 10000 cal. years BP, Tilia was already present in the Jura mountains (18

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Praz Rodet, Mitchell et al. 2001), in the northern Alpine Foreland (17 Rotsee, Lotter 1988; 37 Haslacher See, Küster 1986; 15 Halleswiessee, Handl not publ.) and also in Southeastern Poland (51 Słopiec, Szczepanek 1989; 52 Lake Łukcze, Bałaga 1990). During the Boreal Tilia moved preferably northward over vast areas of Central and Eastern Europe up to the southern and southeastern border of the Baltic Sea und up to the watershed between the Black and Caspian Sea and the Arctic Ocean, around the 60th degree of latitude (73 Polovetsko-Kupanskoye mire, Khotinskiy 1984). The northward and westward migration ended during the Atlantic: The foothills of the Spanish (19 Tramacastilla, Montserrat 1992) and French Pyrenees (20 Ruisseau de Laurenti, Jalut et al. 1992; Reille and Lowe 1993) were reached between 8800 and 8000 cal. years BP, as well as the French Central Massif (24 Lac du Bouchet, Reille and de Beaulieu 1988; 25 La Taphanel, de Beaulieu et al. 1982) and the lowland further north and most of Southern Scandinavia. England, however, and Southern Finland were invaded by Tilia only between 8000 and 7000 cal. years BP. The present northern limit of Tilia (formed by T. cordata) was reached or perhaps partly transgressed between 7000 and 6000 cal. years BP (64 Normannslagen, Moe 1978; 75 Zarutskoe, Elina 1981), yet before the beginning of the Subboreal. Pollen analytical records of Tilia north of its present range in Russia were discussed by Serebryanny (1973), but reliable evidence of a temporary northward shifting of Tilia (cordata) seems to be still weak. The immigration history of Tilia described above indicates different migration rates during different periods of the Holocene. During the Boreal the northward movement of the tree in Central Europe was apparently rather rapid; For the distance of 1150 km from Haslacher See

Fig. 6. Immigration and expansion (first peak) of Tilia. Shown by simplified pollen histograms (mean values of thousand year periods) of selected sites along a line from the Apennine peninsula to the British Isles. Numbers in brackets refer to the reference table in the appendix.

Immigration and expansion of Tilia in Europe since the last Glacial

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(37) at the northern border of the Alps to Hassing Huse Mose (58) in northern Jytland Tilia needed only 1400 years, corresponding to a migration rate of 820 m/year. The distance of about 1200 km from Słopiec (51) in southeastern Poland to the Oslofjord (63) was mastered within 1800 years, corresponding to a migration rate of 670 m/year. Somewhat slower was the migration of lime from east to west in France: The distance of about 500 km from the Vosges (27) to the Normandie (29) was taken in 1400 years, corresponding to a migration rate of 350 m/year. And for the distance of about 320 km from the southwestern border of the Alps (23) to the western Central Massif (25) the migration required 1700 years, corresponding to a migration rate of only 190 m/year. Of course, all these calculations should be taken not too precisely considering the uncertainties of datings and of other sources of error. Anyway, compared with the evaluated migration rates between 300 and 500m/year by Huntley and Birks (1983), the rates calculated here seem to be somewhat higher. A particularly low migration rate of only 50 m/year was found by Birks (1986,1989) in England near the northwestern limit of the distribution range, indicating a gradual retardation of spreading caused very likely by climatic conditions. It might be questioned whether the calculated migration rates are in accordance with the present migration abilities of the tree. All species of the anemochorous genus Tilia are “Winged Flyers”: The diaspores are transported by wind due to a long bract connected with the infructescence, functioning as a wing. Compared with “Plumed Flyers”, like the feathery achenes of many Asteraceae, winged diaspores do not have similar wide ranges of

Fig. 7. Immigration and expansion (first peak) of Tilia. Shown by simplified pollen histograms (mean values of thousand year periods) of selected sites along a line from the Balkan peninsula to Southern Scandinavia. Numbers in brackets refer to the reference table in the appendix.

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propagation, but nonetheless in case of Tilia there have been propagation steps observed up to several kilometres. Therefore, in consideration of the low age of only 10-30 years for first flower development (Firbas 1949), the present migration rates of the tree seem to be in good accordance with the calculated ones for the past After the first arrival of a tree in an area follows usually a phase of establishment of the population and often an expansion, if the species is a major constituent in the vegetation. In pollen diagrams this expansion is recognizable as a first peak in the respective pollen curve (Watts 1973, Birks 1986). The interval between arrival and first mass expansion differs normally from site to site. In case of Tilia a couple of selected and simplified curves (Figs. 6 and 7) demonstrate that these differences range from 400 years (28 Vallee de la Voise) to more than 2500 years as an extreme value (17 Rotsee), with an average of approximately 1000 years. The interval between arrival and first culmination of expansion is obviously the spreading time needed for competition with preceding tree taxa in the Late-glacial and early Holocene forest development. Regarding the ecological behaviour of Tilia the tree belongs, together with Acer, Fraxinus, Ulmus and Alnus, to the group of mesocratic halfshade trees, which have an advantage in competition with protocratic light-demanding trees like Betula, Corylus, Quercus, but a disadvantage in competition with the afterwards following telocratic fullshade trees like Carpinus, Fagus, Abies and Picea. And indeed Tilia decreases together with other mesocratic elements for the benefit of telocratic trees in the second half of the Holocene, beginning at about 6000 cal. years BP. Yet a discussion of all causes of retreat, including also anthropogenous ones, is not intended here. The mass expansion of Tilia during the Holocene - mostly during the Atlantic, in Western France also during the Subboreal - happened preferentially in the western parts of continental western Europe, without being strictly limited to that area. A mass expansion of Tilia is recorded in pollen diagrams of several sites up to values of 20-25 % of TP, in a few extreme cases (Seewiese/Meissner, Stalling 1983; Luderholz/Harz, Chen 1988; both sites in Germany) up to 30-35% of TP, indicating absolute dominance of the tree in the surrounding forests. In England and Fennoscandia as well as in eastern, southeastern and southern parts of Europe mass expansion of Tilia - manifested as high pollen values in diagrams - is by far less recognizable if at all. That leads to the question about the involved species. The answer is difficult in view of the fact, that species identification by pollen analysis is available only for T. cordata and T. platyphyllos and only from few sites. Of course in large areas, where today T. cordata is the only occurring species, we can quite reasonably assume that also during the Late-glacial and the Holocene no other species of Tilia was present. But in Central and Southern Europe, where T. cordata and T. platyphyllos occur jointly, and particularly in Southwestern Europe, where we have to account four or five species, the problem is more complicated and can reliably be solved only by future macrofossil investigations. At present there exists still no information about the history of T. tomentosa and T. rubra. However in Central Europe, with its partly high Tilia pollen values, the few attempts of pollen morphological species identification indicate, that besides T. cordata also T. platyphyllos was a major component of the forest vegetation, although

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Kubitzki K, Münnich KO (1960) Neue C14-Datierungen zur nacheiszeitlichen Waldgeschichte Nordwestdeutschlands. Ber Deutsche Bot Ges 73: 137-146. Küster H (1986) Werden und Wandel der Kulturlandschaft im Alpenvorland. Germania 64: 533-559. Lang G (1994) Quartäre Vegetationsgeschichte Europas. Methoden und Ergebnisse. Fischer, Jena. Latałowa M, Tobolski K (1989) Type Region P-u: Baltic Shore. Acta Palaeobot 29: 109-114. Lotter A (1988) Paläoökologische und paläolimnologische Studie des Rotsees bei Luzern. Pollen, großrest-, diatomeen und sedimentanalytische Untersuchungen. Diss Bot 124: 1-287. Mayer H, Aksoy H (1986) Wälder der Türkei. Fischer, Stuttgart. Meusel H, Jäger E, Rauschert S, Weinert E (1978) Vergleichende Chorologie der zentral-Europäischen Flora. Band II. Fischer, Jena, Text und Karten. Milthers V (1908) Beskrivelse til geologisk kort over Danmark. Kortbladene Faxe og Stevns Klint. Danm Geol Unders I. Raekke 11: 1-291. Michell EAD, van der Knaap WO, van Leeuwen JFN, Buttler, A, Warner BG, Gobat J-M (2001) The palaeoecological history of the Praz-Rodet bog (Swiss Jura) based on pollen, plant macrofossils and testate amoebae (Protozoa). Holocene 11: 65-80. Moe D (1978) Studier over vegetasjonsutviklingen gjennom Holocen på Hardangervidda, Sør-Norge. Part of Dr. thesis. Univ Bergen. Montserrat Marti JM (1992) Evolución glaciar y postglaciar del clima y la vegetación en la Vertiente sur del Pirineo: Estudio palinológico. Monogr Inst Pirenaico Ecol 6: 1-147. Moore PD, Webb JA, Collinson ME (1991) Pollen Analysis. 2nd ed. Blackwell, Oxford. Müller HJ (1972) Pollenanalytische Untersuchungen zum Eisrückzug und zur Vegetationsgeschichte im Vorderrhein- und Lukmaniergebiet. Flora 161: 333-382. Noryskiewicz B, Ralska-Jasiewiczowa M (1989) Type Region P-w: Dobrzyn-Olsztyn Lake Districts. Acta Palaeobot 29: 85-93. Obidowicz A (1989) Type Region P-a: Inner West Carpathians - Nowy Targ Basin. Acta Bot 29: 11-15. Odgaard B V (1994) The Holocene vegetation history of northern West Jutland, Denmark. Opera Bot 123: 1-171. Paul H, Ruoff S (1932) Pollenstatistische und stratigraphische Mooruntersuchungen im südlichen Bayern. II. Teil. Moore in den Gebieten der Isar-, Allgäu- und Rheinvorlandgletscher. Ber Bayer Bot Ges 20: 1-264. Peichlová M (1979) Historie vegetace Broumovska. Diss Bot Inst Acad Sci Pruhonice, not publ. Peschke P (1977) Zur Vegetations- und Besiedlungsgeschichte des Waldviertels (Nieder-österreich). Mitt Komm Quartärforsch Österr Akad Wiss 2: 1-84. Pigott CD (1991) Biological flora of the British Isles 174: Tilia cordata Mill. J Ecol 79: 1147-1207. Pirrus R, Rôuk A-M, Liiva A (1987) Geology and stratigraphy of the reference site of Lake Raigastvere in Saadjärv drumlin field. In: Raukas A, Saarse L (eds) Palaeohydrology of the temperate zone. II Lakes, pp 101-122. Planchais N (1970) Tardiglaciaire et Postglaciaire à Mur-de-Sologne (Loir-et-Cher). Pollen et Spores 12: 381-428. Planchais N (1987) Impact de l’homme lors du remplissage de l’estuaire du Lez (Palavas, Hérault) mis en évidence par l’analyse pollinique. Pollen et Spores 29: 73-88.

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Regnéll J (1989) Vegetation and land use during 6000 years. Palaeoecology of the cultural landscape at two lake sites in southern Skane, Sweden. Lundqua Thesis 27: 1-62. Reille M (1984) Origine de la végétation actuelle de la Corse sud-orientale; analyse pollinique de cinq marais cotiers. Pollen et Spores 26: 43-60. Reille M, de Beaulieu J-L (1988) History of the Wûrm and Holocene vegetation in western Velay (Massif Central, France): A comparison of analysis from three corings at Lac du Bouchet. Rev Palaeobot Palynol 54: 233-248. Reille M, Löwe JJ (1993) A re-evaluation of the vegetation history of the eastern Pyrenees (France) from the end of the last Glacial to the present. Quat Sci Rev 12: 47-77. Roberts N (1998) The Holocene. An Environmental History. 2nd ed. Blackwell, Oxford. Rösch M (1989) Pollenprofil Breitnau-Neuhof: Zum zeitlichen Verlauf der holozänen Vegetationsentwicklung im südlichen Schwarzwald. Carolinea 47: 15-24. Rybníckovâ E, Rybnícek K (1972) Erste Ergebnisse paläogeobotanischer Untersuchungen des Moores bei Vracov, Südmähren. Folia Geobot Phytotax 7: 285-308. Saarse L, Vishnevskaya E, Sarv A, Rajamäe R (1990) Evolution of lakes of Saarema Island. Proc Acad Sci ESSR, Biology 39: 34-45 (in Russian). Schloss S (1979) Pollenanalytische und stratigraphische Untersuchungen im Sewensee. Ein Beitrag zur spät- und postglazialen Vegetationsgeschichte der Südvogesen. Diss Bot 52: 1-138. Schmidt R (1981) Grundzüge der spät- und postglazialen Vegetations- und Klimageschichte des Salzkammergutes (Österreich) aufgrund palynologischer Untersuchungen von See- und Moorprofilen. Mitt Komm Quartärforsch Österr Akad Wiss 3: 1-96. Schmidt R (1983) Pollen und Großreste aus der neolithischen Station Weyregg I am Attersee, Oberösterreich. Fundber Österreich 21: 157-169. Schmidt R, Müller J, Drescher-Schneider R, Krisai R, Szeroczynska K, Baric A (2000) Changes in lake level and trophy at Lake Vrana, a large karstic lake on the Island of Cres (Croatia), with respect to paleoclimate and anthropogenic impacts during the last approx. 16000 years. J Limnol 59: 113-130. Schneider R, Tobolski K (1983) Palynologische und stratigraphische Untersuchungen im Lago di Ganna (Varese, Italien). Bot Helv 93: 115-122. Schneider R, Tobolski K (1985) Lago di Ganna - Late-glacial and holocene environments of a lake in the Southern Alps. In: Lang G (ed) Swiss Lake and Mire Environments during the Last 15000 years. Diss Bot 87: 229-271. Seiwald A (1980) Beiträge zur Vegetationsgeschichte Tirols IV: Natzer Plateau – Villanderer Alm. Ber naturw-med Ver Innsbruck 67: 31-72. Serebryanny LR (1973) Postglacial migration rates of some tree species in the north-western areas of the USSR. Proc III Int Palynol Conf Novosibirsk 1971 (Holocene and marine palynology), pp 14-18 (in Russian with English summary). Smettan H (1985) Pollenanalytische Untersuchungen zur Vegetations- und Siedlungsgeschichte der Umgebung von Sersheim, Kreis Ludwigsburg. Fundber Bad-Württ 10: 367-421. Stalling H (1983) Untersuchungen zur nacheiszeitlichen Vegetationsgeschichte des Meißners (Nordhessen). Flora 174: 357-376.

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Stalling H (1987) Untersuchungen zur spät- und postglazialen Vegetationsgeschichte im Bayerischen Wald. Diss Bot 105: 1-201. Stark P (1925) Die Moore des badischen Bodenseegebietes. I. Die nähere Umgebung von Konstanz. Ber Naturf Ges Freiburg 24: 1-123. Szczepanek K (1982) Development of the peat-bog at Słopiec and the vegetational history of the Swietokrzyskie (Holy Cross) Mts. in the last 10000 years. Acta Palaeobot 22: 117-130. Szczepanek K (1989) Type Region P-j: Swietokrzyskie Mts. (Holy Cross Mts.). Acta Palaeobot 29: 51-56. Tobolski K, Okuniewska-Nowaczyk I (1989) Type Region P-r: Poznan-Gniezno-Kujawy Lake Districts. Acta Palaeobot 29: 77-80. Tolonen M (1985) Palaeoecological reconstruction of vegetation in a prehistoric settlement area, Salo, S W Finland. Ann Bot Fenn 22: 101-116. Tonkov S (1988) Sedimentation and local vegetation development of a reference site in southwestern Bulgaria. In: Lang G, Schlüchter C (eds) Lake, Mire and River environment during the last 15000 years, Balkema, pp 99-101. Tonkov S, Bozilova E (1992) Palaeoecological investigation of Tschokljovo marsh (Konjavska mountain). Ann Sofia Univ, Fac Biol 83, 2: 5-16. Trepp W (1947) Der Lindenmischwald (Tilio-Asperuletum taurinae). Beitr Geobot Landesaufnahme Schweiz 27: 1-128. van Zeist W (1955) Pollen analytical investigations in the northern Netherlands with special reference to the archeology. Acta Bot Neerl 4:1-81. van Zeist W, van der Spoel-Walvius MR (1980) A palynological study of the Late-Glacial and the Postglacial in the Paris basin. Palaeohistoria 22: 67-109. Verbruggen C (1971) Postglaciale landschapsgeschiedenis van Zandig Viaanderen. Thesis Rijksuniv Gent. von Engler A (1909) Monographie der Gattung Tilia. Diss Univ Breslau. Waton PV (1982) A palynological study of the impact of man on the landscape of central southern England with special reference to the chalklands. PhD thesis. Univ Southampton, not publ. Watts WA (1973) Rates of change and stability in vegetation in the perspective of long periods of time. In: Birks HJB, West RG (eds) Quaternary Plant Ecology. Blackwell, Oxford, pp 195-206. Watts WA, Alien JRM, Huntley B, Fritz SC (1996) Vegetation history and climate of the last 15000 years at Laghi di Monticchio, southern Italy. Quat Sci Rev 15: 113-132. Weber CA (1905) Über Litorina- und Prälitorinabildungen der Kieler Förde. Engl Bot Jb 35: 1-54. Wijmstra TA (1969) Palynology of the first 30 meters of a 120 meter deep section in northern Greece. Acta Bot Neerl 18: 511-528.

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APPENDIX Reference Site Table. B with number (in brackets at the end of line) means review with pollen diagram on the corresponding page in Berglund et al. (1996). 1 GR 2 3 BU 4 5 6 8 RO 9 HR 10 SLO 11 I 12 13 14 15 A 16 17 CH 18 19 E 20 F 21 22 23 24 25 26 27 28 29 30 B 31 UK 32 33 34 35 36 37 D 38

loannina, 470m, Bottema 1974 Tenaghi Philippen II, 40m, Wijmstra 1969 Sucho Ezero, 1900m, Bozilova et al. 1990; Bozilova 1995 (B720) Tschokljovo, 870m, Tonkov 1988; Tonkov and Bozilova 1992 (B725) Lake Varna, 0m, Bozilova and Filipova 1986 (B710) Black Sea (A 159), Attanassova 1995 Tãul Zãnogutii, 840m, Farcas et al. 1999 Lake Vrana, 10/15m, Schmidt et al. 2000 Zamedvejca, 300m, Culiberg 1991 (B695) Lago di Monticchio (Monticchio Fen), 656m, Watts et al. 1996 Lago di Trasimeno, 258m, Drescher-Schneider, not publ. Lago di Ganna, 452m, Schneider and Tobolski 1983, 1985 Sommersüß, 870m, Seiwald 1980 Halleswiessee, 781m, Handl, not publ. (B671) Haslau, 565m, Peschke 1977 Rotsee, 419m, Lotter 1988 (B658) Praz Rodet, 1035m, Mitchell et al. 2001 Tramacastilla, 1682m, Monserrat Marti 1992 Ruisseau de Laurenti, 1860m, Jalut et al. 1992; Reille and Lowe 1993 (B616) Palavas, 65m, Planchais 1987 Le Forest-en-Dévoluy, 1460m, de Beaulieu 1977 St. Julien de Ratz, 650m, Clerc 1988 Lac du Bouchet, 1200m, Reille and de Beaulieu 1988 La Taphanel, 975m, De Beaulieu et al. 1982 Mur-de-Sologne, 102m, Planchai 1970 La Goutte Loiselôt, 835m, Edelman 1985 Vallée de la Voise, ca. 100m, van Zeist and van der Spoel-Walvius 1980 La Mailleroye, 3m, Huault and Lefebrvre 1983 (B582) Berlare, l.5m, Verbruggen 1971 (B562) Hockham Mere, 33m, Bennett 1983 (B42) Winchester, 420m, Waton 1982 (B26) Blacka Brook, 270m, Beckett 1981 (B24) Tregaron, 165m, Hibbert and Switsur 1976 (B82) Stafford King’s Pool, 75m, Bartley and Morgan 1990 (B32) Neasham Fen, 46m, Bartley et al. 1976 (B62) Haslacher See, 765m, Küster 1986 (B545) Breitnau-Neuhof, 985m, Rösch 1989 (B530)

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39 40 41 42 43 44 45 46 47 NL 48 SK 49 CZ 50 PL 51 52 53 54 55 56 DK 57 58 59 S 60 61 62 63 N 64 65 LT 66 EST 67 68 FIN 69 70 71 UA 72 73 RUS 74 75 76 F

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Sersheimer Moor, 234m, Smettan 1985 Dösinger Ried, 715m, Stalling 1987 Seelohe, 775m, Hahne 1992 Luttersee, 164m, Chen 1988 Tegeler See, 31m, Brande 1980, 1988 (B521) Melbecker Moor, 25m, Kubitzki and Münnich 1960 Altes Moor, Dörfler 1989 (B517) Süderlügum, Kubitzki and Münnich 1960 Emmen, van Zeist 1955 Vracov, 190m, Rybnícková and Rybnícek 1972 (B491 ) Vernérovice, 450m, Peichlová 1979 (B488) Puscizna Rekovianska, 656m, Obidowicz 1989,1990 (B411 ) Słopiec, 248m, Szczepanek 1982,1989 (B430) Lake Łukcze, 163m, Bałaga 1982,1989,1990 (B437) Lake Skrzetuszewskie, 109m, Tobolski and Okuniewska-Nowaczyk 1989 (B448) Woryty, 105m, Noryskiewicz and Ralska-Jasiewiczowa 1989 (B451) Kluki, 2m, Latałowa and Tobolski 1989 (B463) Holmegaard Bog, 31m, Andersen et al. 1983; Aaby 1986 (B221) Lake Solsø,40m, Odgaard 1994 (B219) Hassing Huse Mose, 10m, Andersen 1993 Lake Krageholmssjön, 43m, Gaillard 1984; Regnéll 1989 (B239) Lake Trummen, 161m, Digerfeldt 1972 (B244) Lake Flarken, 109m, Digerfeldt 1977 (B247) Lake Långa Getssjön, 120m, Florin 1969, 1977 (B256) Kjeldmyr, 87m, Henningsmoen 1980 (B 165) Normannslagen, 1250m, Moe 1978 (B 174) Lake Bebruskas, 160m, Kabailiené 1986, 1987 (B398) Lake Raigastvere, 52m, Pirrus et al. 1987 (B378) Pelisoo, 34m, Saarse et al. 1990 (B371) Lake Vakojärvi, 82m, Donner 1971, 1972 (B298) Hiittenmäensuo, 89m, Gluckert 1976; Tolonen 1985 (B293) Mäyrälampi, 120m, Koivula 1987; Koivula et al. 1994 (B312) Kardashinski swamp, Kremenetski 1995 Dovjok swamp, Kremenetski 1995 Polovetsko-Kupanskoye mire, ca. l50m, Khotinskiy 1977, 1984 Gotnavolok, 88m, Elina 1981; Elina and Filimonova 1987 (B359) Zarutskoe, 20m, Elina 1981 (B358) Etang de Sale/Corse, Im, Reille 1984

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© PENSOFTTowards Publishersbetter Sofia - Moscow

Spassimir Tonkov (ed.) 2003 temporal, spatial and ecological resolution in palaeoecological 43 Aspects of Palynology and... Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 43-60

Towards better temporal, spatial and ecological resolution in palaeoecological reconstructions: the role of pollen monitoring Sheila Hicks Institute of Geosciences, PL 3000, 90014 University of Oulu, Finland E-mail: [email protected]

ABSTRACT Selected points in the historical development of the technique of pollen analysis which have bearing on the temporal, spatial and ecological resolution of the interpretation of fossil pollen assemblages are briefly reviewed. The scientific challenges of the present day, which can be profitably addressed by pollen analysis, are assessed and the reasons for needing better temporal, spatial and ecological resolution in palaeoecologcial reconstructions are detailed. A selection of pollen monitoring results from northern Finland are provided to illustrate the contribution that monitored modern pollen deposition can make towards achieving these higher resolutions for pollen based Holocene reconstructions. Some restrictions and sources of error are highlighted together with possible future developments. KEY WORDS: Pollen monitoring – High resolution – Time – Space – Ecology – Europe

INTRODUCTION The technique of pollen analysis has seen many and varied developments since its introduction more than 80 years ago (von Post 1916, 1967). It continues to be a valuable and widely used tool for reconstructing past vegetation and one which is increasingly and very profitably being linked with other analysis techniques (micro, macro and mega fossils, sediment chemistry and mineral composition, etc.) rather than being the central (and often the only) investigation technique, as it was for many years. From time to time it is salutary to stop and look back over past developments and assess the factors which deliberately or inadvertently determined the course of events, in order to see more clearly the path that can most profitably be followed in the future. This paper presents some glimpses from the past 40 years of pollen analysis but they are essentially views as seen from the northern periphery of Europe and with my personal interpretation. The aim is to explain some aspects of how the present day situation has

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come about and to justify some potential future lines of development. I have pleasure in dedicating the paper to Professor Elissaveta Bozilova. I hope that, in reading it, she too will look back over the years, recognize many of the land marks and remember happy and interesting occasions with colleagues and friends. She has experienced or been involved in all the events described, though viewing them from quite another corner of Europe, and I hope that she will continue to be just as active in those developments that are planned for the future. Towards the end of this paper I will draw attention to pollen monitoring. I would like to think that this topic is close to Elissaveta Bozilova’s heart, and this is another reason for making it the central theme of this article. It also gives me an opportunity to thank her for the many memorable visits to pollen monitoring sites in a vast range of interesting vegetation communities in Bulgaria, from the tops of the Rila mountains to the shores of the Black Sea coast. LANDMARKS FROM THE PAST Many younger pollen analysts will not remember the big jump forward that occurred when radio-carbon dating revealed that the then universally used pollen zones (Jensen 1935,1938; Nilsson 1935; Firbas 1949) were metachronous across Europe and could not, therefore, be used as a time framework in the way that they had been. This led to the introduction of pollen assemblage zones, PAZ’s (Cushing 1967; West 1970; Donner 1971) which could be described for the local situation, correlated with the regional situation and independently dated by radio-carbon. Neither will younger pollen analysts appreciate the many and often heated discussion meetings around this theme which took place prior to the publication establishing chronozones for the Late-glacial and Holocene (Mangerud et al. 1974). These chronozones were given (somewhat unfortunately and confusingly I have always felt), the same names as the Blytt and Sernander units (Blytt 1893; Sernander 1894) which originally referred to different peat beds, were regarded as corresponding to different climate periods and which had become strongly linked with the original (metachronous) pollen zones. This provides us with a starting point for thinking about temporal resolution. During the late 1960s and early 1970s several exciting developments were taking place, the real fruit of which is only now being reaped. Davis was making imaginative progress in investigating how the pollen vegetation relationship could be presented more objectively and even quantified, with her introduction of R-values (Davis 1963), later taken up and extended by Andersen (1970), and with her work involving ‘absolute’ pollen values (Davis 1965, 1966, 1969; also Andersen 1974), the latter calculation being made much easier after Lycopodium tablets (Stockmarr 1971) became available. Tauber’s invention of the ‘pollen trap’ (1965, 1967, 1974, 1977) was another event which caused a great rush of pollen monitoring and a real interest in pollen sources and pollen dispersal. During the 1970s, too, the first numerical analyses of pollen data were being made (Birks et al. 1975a) and isopollen maps constructed (Birks et al. 1975b; Birks and Saarnisto 1975). These approaches all arise in connection with questions about the spatial resolution of the pollen record.

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Many more pollen analysts will remember, or have been involved in, the IGPC project 158 “Palaeohydrological Changes in the Temperate Zone During the Last 15000 years”, part B ‘Lake and mire environments’, strongly led by Berglund and Ralska-Jasiewiczowa which resulted not only in what is familiarly referred to as ‘The Orange Book’ (Berglund 1986) but later also in the equally familiar ‘Green Book’ (Berglund et al. 1996) both weighty tomes and ‘essentials’ for all pollen laboratories. The IGCP project took pollen analysis a big step forward by standardizing field and laboratory procedures across Europe and by creating a network of well dated, uniformly produced and detailed pollen diagrams from similar sized, relatively large basins. The result of this initiative was that everyone started doing things in the same ’approved’ way which initially was excellent but, in the longer term, may well have delayed the development of alternative approaches which were needed to answer questions other than those concerned with regional vegetation history. In terms of temporal and spatial resolution the IGCP project 158 B was able to firmly set up the basic (but of necessity rather coarse resolution) framework for the Holocene against which other studies with a higher spatial (e.g. the ‘small hollows’ of Anderson 1988) or temporal resolution (e.g. from laminated sediments see collections of papers in both Saarnisto and Kahra 1992 and Hicks et al. 1994, also Ralska-Jasciewiczova et al. 1998) could be set. The production of a set of regional pollen profiles in the course of the IGCP 158 B project, coinciding as it did with the establishment of the North American Pollen Database, led on to the establishment of the European Pollen Database (EPD). In practice the IGCP 158 B project played a prominent role in launching the EPD (see Forward by de Beaulieu in Berglund et al. 1996). It is particularly sad that for quite a long part of its existence the EPD both united and split the European pollen community. It has taken years to obliterate the concept, prevalent during the early days, that there is a conflict of status between the ‘data producers’ who have invested a lot of time in perfecting their pollen identification skills and have sat for interminably long hours at the microscope and the ‘data users’, numerically literate researchers who, taking over this vast body of data, would be able to produce dramatic syntheses apparently ‘at the press of a button’. This dichotomy, which unfortunately was felt so very strongly in the early days, arose largely because there were only a handful of researchers who had both skills. Time has shown that much background preparation and analysis is involved before it is possible to ‘press the button’ and that the really rewarding and interesting results arise from projects in which ‘data producers’ and ‘data users’ jointly plan and implement specific research questions. It has now become clear that the very existence of the EPD is an extremely important achievement allowing exciting research possibilities. One very important contribution of the EPD has been the harmonization of pollen morphological taxonomy and the establishment of a clear set of rules for how this is implemented in the database. This is an important contribution to the ecological resolution of pollen based syntheses. This goes hand-in hand with another aspect which has gradually developed over the years, that a great deal of ecological information can come from the nonarboreal pollen types and also from fungal spores (van Geel 1978), fly ash (Renberg and Wik

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1984; Odgaard 1994) and other micro remains. This is a big development compared with the early years of pollen analysis when, essentially, only arboreal pollen was considered. For questions involving archaeology and reconstructions of the cultural landscape there is a need to identify all pollen grains, spores and other related microfossils to the lowest taxonomic level. The possibilities for doing this have been greatly enhanced through the publication of several keys and photographic reference material (Moore et al. 1991; Faegri and Iversen 1989; Andrew 1984; Punt et al. 1976-1995; Reille 1992, 1995, 1998). The importance of using contemporary ecological knowledge to group pollen taxa in terms of specific land use types (Behre 1981; 1986; Vorren 1986; Latałowa 1992) has also become evident. An offspin of the development of databases which had a widespread impact was Grimm’s writing of the Tilia and Tilia·Graph programs (Grimm 1992). Many pollen analysts continue to have a love-hate relationship with Tilia, Tilia·Graph and, more recently, TGview but, a large number of them, nevertheless, could not exist without these programs. At the same time the availability of material in the databases and the urge to make regional syntheses and isopoll maps brought to light the need for an accurate and reliable age-depth model for each pollen profile. Reliable age-depth models are also needed for calculating sediment accumulation rates, which are essential if fossil ‘pollen influx’ more correctly pollen accumulation rates (PARs) are to be used (Hyvärinen 1975, 1976; Seppä 1996). This, in turn, requires a precise appreciation of the error range on these calculations (Bennett 1994; Maher 1972, 1981). This all has relevance for the temporal resolution of palaeo investigations. THE PRESENT SITUATION AND DIRECTIONS FOR THE FUTURE Now, at the beginning of 21st century pollen analysis has branched out into numerous and diverse directions, several of which can trace their routes back to the 1970s. Moreover, a wide range of techniques and tools and a vast body of data and knowledge are available. These include the use of numerical methods for more objective and quantitative analyses, the development of transfer functions to obtain climate data using vegetation as a proxy, the construction of isopoll maps and regional syntheses based on plant biomes, modelling to understand pollen dispersal and source areas of the assemblages being analysed, and the monitoring of modern pollen deposition and the use of pollen accumulation rates rather than the more conventional percentages, to mention just a small selection. Three major problems which are determining the focus of international research at the present time are (1) global climate change, (2) land use and sustainable development and (3) biodiversity. Answers to questions arising from these problems can only come from inter and multidisciplinary research projects but within these projects pollen analysis, through the presently available range of techniques, has a definite role to play. Such research projects must increasingly involve quantification and a much higher temporal, spatial and even ecological resolution than has previously been employed. At the same time, however, syntheses will need to cover larger and larger areas.

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WHY AND HOW TO IMPROVE THE TEMPORAL, ECOLOGICAL AND SPATIAL RESOLUTION OF PALAEOECOLOGICAL RECONSTRUCTIONS 1. Temporal resolution i.e. how long a period of time is encompassed by one pollen sample and the period of time between samples We do not always stop to think how many years of vegetation history (and change) one pollen sample from a sediment sequence covers. It may be anything from 1 (in the case of a varve) to 100 years! Neither do we always take into consideration how many years are ‘blank’ between the individual pollen samples in a series. Maybe the aspect we wish to investigate happened in just those sections of the profile that we have chosen not to sample! How often do we falsely think that an event is abrupt or of short duration simply because the samples in our pollen diagram are rather widely spaced or the rate of sediment accumulation varies through the sediment profile? The research questions of today force us to look at rates of change and abrupt events and the degree to which these are synchronous or non-synchronous over areas of continental size. Such investigations require a clear knowledge of the temporal resolution of the pollen record and also of the accuracy of the dating of this record. Situations where the temporal resolution and precise dating become critical include: • Comparing and contrasting events at two or more widely separated sites at one point in time and determining whether they occurred rapidly or took several 10s of years • Investigating whether the same event is happening contemporaneously at all sites or in a sequence: transgressing from one site to the next, and the speed of such movement • Comparing the pollen record with another palaeoenvironmental record that has a high temporal resolution e.g. the annual dendro record • Comparing a vegetation change with archaeological evidence to assess if they can be related or not • Producing PARs from a sediment profile The temporal resolution can only be improved by selecting rapidly accumulating sediments and taking samples which cover a small depth range of the sediment core (e.g. 2 mm rather than 1 cm, individual varves rather than groups of varves). This in turn, however, requires a much larger surface area of sediment in order to obtain a sufficient quantity of pollen to be statistically reliable. Such a high resolution sampling must then be coupled with continguous sampling if the results are to be meaningful, which in turn increases the work load to such an extent that it may only be feasible to analyses relatively short sections of cores. Naturally the sediment core must also be accurately dated so that the number of years covered by each of these thin contiguous samples is known. Similarly the type of sediment and sedimentary environment must be known. For sediments where mixing occurs during the process of sedimentation a very thin sample may have no meaning in terms of sedimentation time.

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2. Ecological resolution i.e. the taxonomic precision with which plant communities can be reconstructed from a pollen assemblage Pollen analysts know only too well the restrictions imposed on their vegetation reconstructions by the fact that certain pollen morphological types are the same for a whole family of plants and that it is only for certain genera that it is possible to distinguish individual species. This means that there are real limits to the degree of ecological resolution that is attainable. Traditionally in these situations palaeoecologists supplement pollen data with plant macro-fossil data. Other auxiliary environmental information such as edaphic and hydrological conditions, fungal, charcoal and insect evidence can profitably be utilized in the same way. The questions of today which focus on the potential loss of biodiversity require a really high ecological resolution and, therefore, cannot be addressed by pollen analysis alone, although it should be possible to follow coarse changes over long periods of time. However when it is land use, land use change and sustainable development which are the focus the ecological resolution of the pollen record can often be improved sufficiently to distinguish these changes. In some instances, too, some ecological imprecision in the pollen record can be compensated for by employing present day ecological knowledge. The more impoverished the natural flora of an area the more possible this becomes. In northern Finnish Lapland, for example, where the range of plant species is far fewer than in areas with a calcareous bedrock and more favourable climate, an ‘inclusive’ pollen type such as e.g. Aster type (which Moore et al. 1991 describe as including the genera Bidens, Galinosoga, Filago, Gnaphalium, Senecio, Tussilago, Petasites, Antennaria, Anaphalis, Inula, Conyza, Pulicaria, Solidago, Bellis, Aster, Arnica, Erigeron, Eupatorium, Carduus and possible more) on present day ecological grounds is only likely to originate from the following plant species: Gnaphalium norvegicum, G. supinum, Petasites frigidus, Antennaria dioica, A. nordhageniana, A. alpinum, A. canescens, Solidago virgaurea, Erigeron acer ssp. politus and Arnica angustifolia (Hamet-Ahti et al. 1984) of which only Solidago virgaurea and Antennaria dioica are at all common. Therefore, if this pollen type is found in large quantities (such that it must have a local origin rather than being a single grain transported from much further south) it is likely to represent one of these species and a good reference collection should help in indicating which. Solidago can be identified separately. In this way the ecological resolution of the evidence can be improved. This approach is valid for the more recent history of an area when plant records exist and climate and edaphic conditions have remained constant. Naturally, however, the further back in time one goes the less feasible this becomes and the greater the likelihood that other taxa, though absent today, were present. Late glacial floras, in particular, are likely to have been very different and, in such situations, the ambiguous pollen type remains ambiguous. When the pollen assemblage contains a few big pollen producers and a range of other different pollen taxa which are present in only very small amounts or when the pollen morphological types include a wide range of plant species extra information can be gained from ecological grouping (cf. Behre 1981, 1986) or from using a completely different pollen

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sum (i.e. expressing components as a percentage of just one specified ecological community rather than of total terrestrial pollen). Numerical techniques such as rarefaction analysis (Birks and Line 1992) can also illuminate changes in the diversity of plant communities and quantify these changes between different time periods covered in the same profile. 3. Spatial resolution i.e. the area of vegetation covered by a pollen assemblage and the degree of detail determinable within that area When interpreting the history of an area, whether it be for land use or climate it is necessary to know how ‘wide a picture’ the pollen assemblage is providing – are there parts of the story that remain unobserved because they are happening at the edge of the pollen catchment area or are too thinly distributed through it (Sugita et al. 1997)? Knowledge of the spatial resolution of a pollen assemblage becomes particularly important in land use studies, in looking at both anthropogenic and fire-induced clearings and in delimiting the areal extent of specific vegetation communities (Gaillard et al. 1998; Broström et al. 1999; Sugita et al. 1999). The conventional way of interpreting the spatial aspect of a pollen assemblage is in terms of local, extra local, regional and long distance components. These same terms are used to describe both pollen dispersal (movement of pollen from the plant of origin to the point of preservation) and pollen deposition (the relative distance of the source area from which the different pollen grains deposited at a given point have come), (Faegri and Iversen 1989; Moore et al. 1991; Tauber 1977; Jacobson and Bradshaw 1981; Janssen 1984). Pollen analysts know that the fossil pollen assemblage contains all these elements and intuitatively separate them out i.e. Fagus or Juglans pollen found in northern Finland is automatically classed as ‘long distance’in origin while Cyperaceae pollen found in a Carex peat profile is classed as ‘local’ etc. However, the intermediate distances are more difficult to predict and the exact quantity of pollen in each category is usually unknown. Moreover, one rarely stops to think that a common pollen type, e.g. Betula in northern Finland, could have originated in all four source categories. When results are expressed as a percentage of total pollen and when it is remembered that different plants have different pollen productivities, then the reconstruction of the mosaic of vegetation communities within a specified area around the sampling point is open to many uncertainties. The models developed by Sugita (1993, 1994, 1998, see also Jackson and Lyford 1999 and Davis 2000) clarify this spatial resolution by introducing the concept of relevant source area of pollen and background pollen. It is only possible to reconstruct different vegetation communities within the relevant source area of pollen for beyond it the background pollen gives an averaged ‘amalgamated’ picture of the different vegetation communities that exist. Even so the exact positioning of the relevant source area requires a lot of data (distance weighted plant abundance, the pollen productivity of each taxon, the fall speed of each pollen type, wind speed and basin size).

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THE CONTRIBUTION THAT MONITORING POLLEN DEPOSITION CAN MAKE This paper will focus on just one technique which can contribute towards improving the resolution of and quantifying palaeoecological reconstructions, that of monitoring modern pollen deposition by means of pollen traps. Pollen analysts have always been aware that the ‘present is the key to the past’ and have frequently and successfully used moss polsters or lake surface samples as reference material for both analogue and more quantitative approaches to interpreting fossil assemblages (Wright 1967; Ritchie 1974; Gaillard et al. 1998; Jackson 1991; Jackson and Kearsley 1998; Calcote 1995; Hjelle 1998; Broström et al. 1998). The extra dimension attainable through using pollen traps compared with moss polsters for modern analogue situations is the ability to calculate ‘influx’ – pollen deposition as grains cm-2 year-1. This, as is evident from the historical overview given earlier, was well appreciated by Tauber in the 1970’s as, even earlier, the fossil equivalent: pollen accumulation rates had been appreciated by Davis. However, despite the initial interest in ‘Tauber traps’ the results obtained were not always immediately interpretable and it was not until a quarter of a century later that the Pollen Monitoring Programme (PMP) was set up (Hicks et al. 1996, 1999 ) as a Work Group within the INQUA Holocene Commission. Monitoring pollen deposition involves using traps of the type designed by Tauber but modified so that they can stay in the field the whole year round. The are placed so as to represent as closely as possible pollen deposition on a terrestrial site (primarily a mire). Monitoring localities are related to specific vegetation communities and are designed to reflect ecotone changes from one community to the next. PMP results also go into a database (PMPdata) which follows the format of the EPD and the other major pollen databases. The advantages of results obtained from monitoring pollen deposition are: • They enable quantification (grains cm-2 year-1) because monitoring is happening under known and controlled conditions. • They have an annual temporal resolution – data is collected yearly, always at the end of the flowering season and monitoring continues uninterrupted throughout a whole calendar year • The coverage of individual plant species can be mapped in concentric rings around the pollen trap thus allowing distance weighted plant abundance to be calculated. This vegetation mapping can be extended over several kilometres using remote sensing of air photos and delimiting ecologically significant plants and/or vegetation communities. This contributes to the spatial resolution. • The plants in the immediate vicinity of the traps are known and provide a source of reference pollen material. At the same time the pollen material collected in the traps is fresh and well preserved. This combination of circumstances potentially allows pollen identification at a lower taxonomic level for ambiguous pollen types which are abundantly represented in the traps, thus increasing the ecological resolution.

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• Because pollen monitoring methods are standardized and all meta data relative to the monitoring site recorded in a uniform manner, meaningful comparisons can be made between different geographical areas and different vegetation communities. This contributes to the evaluation of models of pollen dispersal. • Because data are being collected at the same site over a series of years they can be calibrated with other comparable time series (e.g. meteorological records). In this way annual pollen deposition can contribute as a climate proxy. EXAMPLES FROM NORTH FINLAND A selection of results from a 20 year pollen monitoring programme in northern Finland serve to illustrate the points set out above. Figure 1. shows annual pollen deposition (grains cm-2 year-1) at monitoring site P9 (Palomaa) which is situated at the northern limit of continuous pine forest in eastern Finnish Lapland. This is an ecotone situation. To the south of the trap locality lies a vast zone of pine dominated forest and to the north is the area of mountain birch woodland in which islands of pine forest are scattered. The monitoring site itself is a small mire (1.5 hectares in size) which is dominated by sedge and cotton grass species. The vegetation within the vicinity of the mire is shown in Figure 2. Two points are immediately obvious: • Pollen of the locally important tree species, Betula and Pinus dominates the assemblages. • The variation in the quantity of pollen from one year to the next is enormous. That this annual variation is real can be seen from figure 3, where just the annual deposition curve for Pinus is shown for 10 sites located on a north-south transect which stretches from the treeless arctic-alpine areas, through birch woodland and pine forest to forest with birch, pine and spruce and finally spruce dominated forests. In nearly all situations the ‘high’ and ‘low’ Pinus pollen years are the same. If the 20 year monitoring series is averaged then the Pinus values at each of the monitoring points on the transect take on a meaning in terms of the local vegetation such that sites which are >10 km from pine trees have Pinus pollen deposition values of <300 grains cm-2 year-1, those where pines are locally present but very scattered have values 500 - 1500, those within open pine forest 1500 – 2000 and those in dense pine forest >2000 grains cm-2 year-1. This difference in indicative value between the pollen deposition of individual years and the long average annual pollen deposition dramatically illustrates the importance of knowing the temporal resolution of the pollen sample. Investigations (McCarroll et al. in press) have shown that the annual Pinus deposition value can be calibrated with July temperature of the year prior to anthesis, whereas, clearly when the temporal resolution is in tens of years the deposition value is related to the abundance of pine trees in the vicinity of the sampling site. The results presented for P9 are from the centre of a mire of 200 m diameter and 1.5 hectares in area and those for the sites along the transect are from similarly sized mires (0.5

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mountain birch woodland individual pines in mountain birch woodland little or no vegetation sedge mire dwarf shrub mire

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Fig. 2. Vegetation map of the area around pollen monitoring station P9, classified by remote sensing from airphotos.

– 2.0 hectares in size, two exceptionally > 10 hectares). However, if within this same pine dominated forest zone monitoring takes place, not in the centre of a mire but within the forest itself, then average deposition values are some 3 times higher (Hicks 2001). Here the spatial dimension comes into play. Prentice (1985, 1988) has published a model for deposition of pollen at a single point (i.e. comparable to the pollen trap in the centre of a mire) which predicts that the larger the opening in the forest (basin size) the smaller the amount of pollen being deposited in it. The trap results clearly validate this with pollen quantities falling systematically from within the forest, through a small opening to beyond the presence of pine. The spatial dimension, however, is normally conceived in another way – namely the area around the pollen deposition site which is reflected in the pollen assemblage. A crude

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Annual deposition of Pinus pollen 12000

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Fig. 3. Annual deposition of Pinus pollen for the period 1982-2001 at 10 monitoring stations located along a north-south transect in Finnish Lapland.

comparison of vegetation coverage in circles of increasing size around the pollen trap, even in circles ‘skewed’ to take into account wind direction and speed at the time of flowering (see Hicks et al. 1997) shows that that the vegetation percentage and pollen percentage correlation is not very close. This is in keeping with Sugita’s model that the relevant source area is reflected in only a proportion of the total pollen assemblage and that the background pollen comprises more than half of the pollen assemblage (Sugita 1994). Calculating the distance weighted plant abundance in concentric rings (or preferably rings skewed for wind direction and speed) and comparing actual areal coverage of plant taxa or vegetation units and the corresponding pollen deposition can be expected to give a more detailed and objective assessment of the spatial dimension. To be able to use such data as input to Sugita’s model at least 30 pollen monitoring sites within a similar vegetation zone together with distance weighted vegetation analyses are required and, unfortunately at the present time such a quantity of data are not available. However the potential for model validation is clear. TRANSFERRING OF MODERN POLLEN DEPOSITION TO FOSSIL PARs The pollen trap results demonstrate that it is possible to use pollen ‘influx’ values in two ways: as a proxy for summer temperature and as an indicator of the abundance and density of selected taxa. This sets great challenges in terms of obtaining the same information from fossil pollen sequences. If it was possible to obtain the same annual resolution from

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fossil sequences then the PARs of selected taxa (e.g. Pinus) could be used to give a continuous record of changing July temperature. Laminated sediments could potentially provide this record but it is known that pollen deposition in lakes involves different processes from that on land. To sample peat layers sufficiently precisely that each layer represents only one year, and a complete year at that, may not be possible. Work is in progress on this and preliminary results are sufficiently encouraging that the endeavour is continuing. Surprisingly, Hicks and Hyvärinen (1999), were able to demonstrate that long term average PARs from pollen traps, lake sediments and peat profiles within the same vegetation region are numerically similar. It could very well be that it is the basin size (opening within the forest) that is the controlling factor. This raises another point, when comparing the numerical value of fossil PARs between sites or with modern pollen deposition comparisons are only valid for similarly sized openings in the forest cover. A bigger problem when using fossil PARs is their accuracy. Pollen deposition in traps is calculated relative to added Lycopodium spores and the confidence limits on the resulting figure depends very much on the number of Lycopodium spores counted relative to the number of pollen grains counted (Maher 1981; Bennett 1994). The range in this figure for the trap results (which if too few Lycopodium spores are added can be quite large) can be seen from the Appendix in Hicks 2001. When fossil PARs are considered there is the additional uncertainty caused by the calculation of sediment accumulation rates (Bennett 1994). For these reasons taking just the numerical value and using it at face value to indicate the density of a specific tree taxon, or taking a continuous series as representing annual variation in temperature, is highly risky. POSSIBLE FUTURE DEVELOPMENTS The way in which pollen monitoring results throw light on the significance of the temporal resolution of the pollen record and the potential that they have for evaluating models concerned with the spatial resolution of the pollen record, indicates that this line of approach is worth continuing. Profitable lines of development could be: • Increase the density of the pollen monitoring network and the range of vegetation types being monitored • Further develop PMP data (the Pollen Monitoring Programme database) and make it publicly available • Obtain annual resolution from fast growing peat profiles • Link annual pollen values with other annually measured environmental variables eg. tree-rings, speleotherms records, chemistry from laminated sediments ACKNOWLEDGEMENTS The vegetation map illustrated in Figure 2 has been produced by Kirsi Valta-Hulkkonen and some of the pollen counts illustrated in Figures 1 and 3 have been made by Raija-Liisa

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Huttunen and Jacqueline van Leeuwen. I would like to thank all three of these people for their contributions. I am also very grateful to Keith Bennett for helpful comments on an earlier version of the text. REFERENCES Andersen STh (1970) The relative pollen productivity and pollen representation of north European trees and correction factors for tree pollen spectra determined by surface pollen analysis from forest hollows. Danm Geol Unders II Series 96: 1-99. Andersen STh (1974) Wind conditions and pollen deposition in a mixed deciduous forest. Grana 14: 64-77. Andersen STh (1988) Changes in agricultural practices in the Holocene indicated in a pollen diagram from a small hollow in Denmark. In: Birks H, Birks HJB, Kaland P-E, Moe D (eds) The Cultural landscape: Past Present and Future. Cambridge Univ Press, Cambridge, pp 395-407. Andrew R (1984) A practical guide to the British Flora. Quaternary Research Association Technical Guide 1. Behre K-E (1981) The interpretation of anthropogenic indicators in pollen diagrams. Pollen et Spores 23: 225-245. Behre K-E (ed) (1986) Anthropogenic Indicators in Pollen Diagrams. Balkema, Roterdam. Bennett KD (1994) Confidence intervals for age estimates and deposition times in late-Quaternary sediment sequences. Holocene 4: 337-348. Berglund BE (ed) (1986) Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley & Sons, Chichester. Berglund BE, Birks HJB, Ralska-Jasiewiczowa M, Wright HEJr (eds) (1996) Palaeoecological Events During the Last 15 000 Years. Regional Synthesis of Palaeoecological Studies of Lakes and Mires in Europe. John Wiley & Sons, Chichester. Birks HJB, Line JM (1992) The use of rarefaction analysis for estimating palynological richness from Quaternary pollen-analytical data. Holocene 2: 1-10. Birks HJB, Saarnisto M (1975) Isopollen maps and principal components analysis of Finnish pollen data for 4000, 6000 and 8000 years ago. Boreas 4: 77-96. Birks HJB, Deacon J, Peglar SM (1975) Pollen maps for the British Isles 5000 years ago. Proc R Soc B 189: 87-105. Birks HJB, Webb T III, Berti AA (1975) Numerical analysis of pollen samples from Central Canada: a comparison of methods. Rev Palaeobot Palynol 20: 133-169. Blytt A (1893) Zur Geschichte der Nordeuropäischen besonders der Norwegischen Flora. Bot Jb 17, Beibl 41: 1-43. Broström A, Gaillard M-J, Ihse M, Odgaard B (1998) Pollen-landscape relationships in modern analogues of ancient cultural landscapes in southern Sweden – a first step towards quantification of vegetation openness in the past. Veget Hist Archaeobot 7: 189-201. Calcote R (1995) Pollen source area and pollen productivity: evidence from forest hollows. J Ecol 83: 591-602.

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Cushing EJ (1967) Late-Wisconsin pollen stratigraphy and the glacial sequence in Minnesota. In: Cushing EJ, Wright HEJr (eds) Quaternary Palaeoecology. Yale Univ Press, New Haven, pp 59-88. Davis MB (1963) On the theory of pollen analysis. Amer J Sci 261: 897-912. Davis MB (1965) A method for determination of absolute pollen frequency. In: Kummel BG, Raup DM (eds) Handbook of Palaeontological techniques. Freeman, San Francisco, pp 647-686. Davis MB (1966) Determination of absolute pollen frequency. Ecology 47: 310-311. Davis MB (1969) Palynology and environmental history during the Quaternary period. Amer Sci 57: 317-332. Davis MB (2000) Palynology after Y2K – understanding the source area of pollen sediments. Ann Rev Earth Planet Sci 28: 1-18. Donner JJ (1971) Towards a stratigraphical division of the Finnish Quaternary. Comment PhysMath 41: 281-305. Faegri K, Iversen J (1989) Textbook of pollen analysis 4th ed. John Wiley & Sons, Chichester. Firbas F (1949) Spät- und nacheiszeitliche Waldgeschichte Mittel-Europas nördlich der Alpen 1. Allgemeine Waldgeschichte, Jena. Gaillard M-J, Birks HJB, Ihse M, Runborg S (1998) Pollen/landscape calibration based on modern pollen assemblages from surface sediment samples and landscape mapping – a pilot study in south Sweden. In: Gaillard M-J, Berglund BE (eds) Quantification of land surface cleared from forests during the Holocene–modern pollen/vegetation/landscape relationships as an aid to the intercomparison of fossil pollen data. Paläoklimaforschung 27: 31-55. van Geel B (1978) A palaeoecological study of Holocene peat bog sections in Germany and The Netherlands based on the analysis of pollen spores and macro- and microscopic remains of fungi algae cormophytes and animals. Rev Palaeobot Palynol 25: 1-120. Grimm EC (1992) Tilia and Tilia-graph: Pollen spreadsheet and graphics programs. Programs and Abstracts 8th International Palynological Congress Aix-en-Provence September 6-12 1992, p 56. Hicks S (2001) The use of annual arboreal pollen deposition values for delimiting tree-lines in the landscape and exploring models of pollen dispersal. Rev Palaeobot Palynol 117: 1-29. Hicks S, Hyvärinen H (1999) Pollen influx values measured in different sedimentary environments and their palaeoecological implications. Grana 38: 228-242. Hicks S, Ammann B, Latałowa M, Pardoe H, Tinsley H (eds) (1996) European Pollen Monitoring Programme: Project description and guidelines. Hicks S, Miller U, Saarnisto M (eds) (1994) Laminated Sediments. PACT 41. Hicks S, Pellikka P, Eeronheimo H (1997) The relationship of modern pollen deposition to local and regional vegetation in the Pallas area using high accuracy numerical vegetation mapping. Forestry Research Institute Reports 623: 37-47. Hicks S, Tinsley H, Pardoe H, Cundill P (1999) Supplement to the guidelines of European Pollen Monitoring Programme. Hjelle K L (1998) Relationships between modern pollen deposition and the vegetation in mown and grazed communities in western Norway and their application to the interpretation of past cultural activity. University of Bergen, Norway.

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Hyvärinen H (1975) Absolute and relative pollen diagrams from northernmost Fennoscandia. Fennia 142: 1-23. Hyvärinen H 1976 Flandrian pollen deposition rates and tree-line history in northern Fennoscandia. Boreas 5: 163-175. Hämet-Ahti L, Suominen J, Ulvinen T, Uotila P, Vuokko S (1984) Retkeilykasvio. Suomen Luonnonsuojelun Tuki Oy, Helsinki. Jackson ST (1991) Pollen representation of vegetational patterns along an elevational gradient. J Veget Sci 2: 613-624. Jackson ST, Kearley JB (1998) Quantitative representation of local forest composition in forestfloor pollen assemblages. J Ecol 86: 474-490. Jackson ST, Lyford ME (1999) Pollen dispersal models in Quaternary plant ecology: assumptions parameters and prescriptions. Bot Rev 65: 39-75. Jacobson GL, Bradshaw RHW (1981) The selection of sites for palaeoenvironmental studies. Quat Res 16: 80-96. Janssen CR (1984) Modern pollen assemblages and vegetation in the Myrtle lake peatland Minnesota. Ecol Monogr 54: 213-252. Jenssen K (1935) Archaeological dating in the history of north Jutland’s vegetation. Acta Archaeologica 5. Jenssen K (1939) Some west Baltic pollen diagrams. Quartär 1: 124-139. Latałowa M (1992) Man and vegetation in the pollen diagrams from Wolin island (NW Poland). Acta Palaeobot 32: 123-249. Maher LJJr (1972) Nomograms for computing 95% confidence limits on pollen data. Rev Palaeobot Palynol 13: 85-93. Maher LJ Jr (1981) Statistics for microfossil concentration measurements employing samples spiked with marker grains. Rev Palaeobot Palynol 32: 153-191. Mangerud J, Andersen STh, Berglund BE, Donner JJ (1974) Quaternary stratigraphy of Norden a proposal for terminology and classification. Boreas 3: 109-126. McCarroll D, Jalkanen R, Hicks S, Tuovinen M, Pawellek F, Eckstein D, Schmitt U, Autio J, Heikkinen O (in press) Multi-proxy dendroclimatology: a pilot study in northern Finland. Holocene. Moore P, Webb JA, Collinson ME (1991) Pollen Analysis. 2nd ed. Blackwell, Oxford. Nilsson T (1935) Die pollenanalytische Zonengliederung der spat- und post-glazialen Bildungen Schonens. Geol Fören Stockh Förh 57: 385-562. Odgaard BV (1994) The use of spheroidal carbonaceous particles for quantifying modern pollen deposition rates. Rev Palaeobot Palynol 82: 157-164. von Post L (1916) Skogsträdpollen I sydsvenska torvmosselagerföljder. Forh 16 Skand Naturforsk Mote Kristiania 1916, Kristiania, Oslo, pp 433-465. von Post L (1967) Forest tree pollen in South Swedish peat bog deposits. Pollen et Spores 9: 375-401 (Translation of von Post 1916). Prentice IC (1985) Pollen representation source area and basin size: towards a unified theory of pollen analysis. Quat Res 23: 189-213.

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Prentice IC (1988) Records of vegetation in time and space: the principles of pollen analysis. In: Huntley B, Web T III (eds) Vegetation history. Kluwer, Dordrecht, pp 17-42. Punt W, Blackmore S, Clarke CGS, Hoen PP (1976-1995) The Northwest European Pollen flora. Elsevier Science, Amsterdam. Ralska-Jasiewiczowa M, Goslar T, Madeyska T, Starkel L (1998) Lake Gościaz central Poland. A monographic study. Part 1 W. Szafer Institute of Botany, Polish Academy of Sciences, Kraków. Reille M (1992) Pollen et Spores d’Europe et d’Afrique du nord. Marseille. Reille M (1995) Pollen et Spores d’Europe et d’Afrique du nord. Supplement 1. Marseille. Reille M (1998) Pollen et Spores d’Europe et d’Afrique du nord. Supplement 2. Marseille. Renberg I, Wik M (1984) Dating recent lake sediments by soot particle counting. Verh Internat Verein Limnol 22: 712-18. Ritchie JC (1974) Modern pollen assemblages near the arctic tree line Mackenzie Delta region Northwest Territories. Can J Bot 52: 381-396. Saarnisto M, Kahra A (1992) INQUA Commission for the Study of the Holocene Working Group on Laminated sediments. Geological Survey of Finland, Special Paper 14. Seppä H (1996) Post-glacial dynamics of vegetation and tree-lines in the far north of Fennoscandia. Fennia 174: 1-96. Sernander R (1894) Studier öfver den Gotländska vegetationens utvecklingshistoria. Akademisk afhandling, Uppsala. Stockmarr J (1971) Tablets with spores used in absolute pollen analysis. Pollen et Spores 13: 615-621. Sugita S (1993) A model of pollen source area for an entire lake surface. Quat Res 39: 239-244. Sugita S (1994) Pollen representation of vegetation in Quaternary sediments: theory and method in patchy vegetation. J Ecol 82: 881-897. Sugita S (1998) Modelling pollen representation of vegetation. In: Gaillard M-J, Berglund BE (eds) Quantification of land surface cleared from forests during the Holocene – modern pollen/ vegetation/landscape relationships as an aid to the intercomparison of fossil pollen data. Paläoklimaforschung 27: 1-16. Sugita S, MacDonald GM, Larsen CPS (1997) Reconstruction of fire disturbance and forest succession from fossil pollen in lake sediments: potential and limitations. In: Clark JS, Cachier H, Goldammer JG, Stocks B (eds) Sediment records of biomass burning and global change. NATO ASI Series 151: 387-412. Sugita S, Gaillard M-J, Broström A (1999) Landscape openness and pollen records: A simulation approach. Holocene 9: 409-421. Tauber H (1965) Differential pollen dispersion and the interpretation of pollen diagrams. Geological Survey of Denmark II Series 89: 1-69. Tauber H (1967) Investigations of the mode of pollen transfer in forested areas. Rev Palaeobot Palynol 3: 277-286. Tauber H (1974) A static non-overload pollen collector. New Phytol 73: 359-369. Tauber H (1977) Investigations of Aerial Pollen Transport in a Forested Area. Dansk Botanisk Arkiv 32: 1-121.

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Vorren K-D (1986) The impact of early agriculture on the vegetation of northern Norway - a discussion of anthropogenic indicators in biostratigraphical data. In: Behre KE (ed) Anthropogenic Indicators in Pollen Diagrams. Balkema, Roterdam, pp 1-18. West RW (1970) Pollen zones in the Pleistocene of Great Britain and their correlation. New Phytol 69: 1179-1183. Wright HEJr (1967) The use of surface samples in Quaternary pollen analysis. Rev Palaeobot Palynol 2: 321-330.

© PENSOFTLate Publishers Holocene Sofia - Moscow

Spassimir Tonkov (ed.) 2003 vegetation development on the island of Fårö,Aspects Gotland, Sweden 61 of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 61-80

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden Juliana Atanassova1, Lars-König Königsson† and Sheila Hicks2

1

Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria. E-mail: [email protected] 2 Institute of Geosciences, PL 3000, 90014 University of Oulu, Finland

ABSTRACT Three pollen diagrams are presented from the island Fårö, north east Gotland, in the Baltic Sea. These are interpreted in terms of the evolution of the island and the history of its alvar vegation, pine forests and cultivated land. The sediment records cover only the past 1500 years or so. At the time when the lake basins were becoming isolated from the sea, slightly before AD 1200, i.e. late Viking Age-Early Medieval time, the island supported an open xerophytic/heliophytic vegetation and, in some areas, deciduous thermophilous trees were present. Later changes saw the disappearance of this deciduous, thermophilous element and the expansion of cultivated areas. With the increase in animal husbandry from 17th century onwards, the landscape became more open and what forest remained was dominated by pine, as at the present day. KEY WORDS: Alvar vegetation – Baltic island – Pollen – Dinoflagellates – Cultivation

INTRODUCTION There are several islands within the Baltic on which a characteristic xerophytic so-called alvar vegetation occurs, of which Fårö, the topic of this paper, is one. This same vegetation type is also found on the mainland of Estonia and in northern Latvia and has affinities with the steppe vegetation along the Black Sea coast in northern Bulgaria. It was long a matter of debate as to whether the alvar is a naturally occurring vegetation type or whether it has come into being as the result of human activities, particularly in connection with grazing. The Baltic islands and their alvar vegetation always fascinated Professor Lars-König Königsson, ‘Knix,’ who not only spent a great deal of his own research activities in unravelling their history (Königsson 1968) but inspired many of his students and colleagues to do the same (Påhlsson

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Juliana Atanassova, Lars-König Königsson and Sheila Hicks

1977; Eriksson 1992; Alm-Kübler 2001; Poska 2001). Knix’s love of the alvar arose from his having been born on Öland and having spent much of his life wandering through its floristically rich and varied landscape. Naturally, therefore, he was also intrigued by the history of the island, so rich in archaeological finds, and in its relationship with the other islands of the Baltic. In the early 1990s he instigated a research programme in which members of the Quaternary Department of Uppsala University, Sweden co-operated with members of the Department of Botany at the University of Sofia, Bulgaria to look at the history and development of xerothermic vegetation and cultural steppes which occur in both of these countries and to assess their similarities and differences focusing on the underlying controlling factors of climate, edaphic conditions and the role of people. The material presented here forms one of the last publications to come out of this cooperative research programme. The topic brings together three aspects which distinguished Knix’s work: the history of alvar vegetation, the evolution of the cultural landscape, and an island in the Baltic. The Swedish-Bulgarian link is paramount. Dr. Juliana Atanssova, the key researcher for this Swedish, Baltic island: Fårö, is Bulgarian. In publishing this work we wish to honour Professor Elissaveta Bozilova, the driving force of Bulgarian pollen analysis and palaeoecology for so many years. We know that she has had many happy and inspiring field excursions through alvar/steppe vegetation with Knix and we hope that by means of this Fårö report she will feel that Knix, too, is joining in her celebrations. Although Knix was involved in preparing part of a first draft of this text, due to his untimely death, we have, unfortunately, not been able to draw on his wealth of botanical and archaeological knowledge in writing this present version. Inevitably, therefore, the material presented is not as completely evaluated as he would have wished. We hope, however, that it provides one extra piece towards the whole picture of the history of the Baltic islands. We focus on the age of Fårö and its emergence from the sea, the age, character and changes through time of the alvar vegetation, and the development of the cultural landscape. This is achieved through the pollen analysis of three sediment profiles for which we present different types of pollen diagrams – both complete and simplified, this being the way in which Knix had intended to proceed. GEOLOGICAL HISTORY OF THE BALTIC BASIN, THE LOCATION OF FÅRÖ AND ITS CLIMATE AND VEGETATION CHARACTERISTICS The Baltic Sea is part of a geosyncline. The sedimentary rocks comprising it form a system in which there are some very pronounced scarps, locally termed klints. Cambrian, Ordovician, Silurian and Devonian strata outcrop in that order from the periphery towards the centre of the syncline. Little is known of the history of the Baltic basin between the Devonian and the Pleistocene. During the maximum of the Weichselian glaciation the whole of the Baltic basin was occupied by a continental ice sheet. Deglaciation occurred between c. 13500 – 13000 14C BP (Berglund 1979; Ringberg 1988) and 9000 14C BP (Andrén 1990). The subsequent history of the Baltic reflects the interplay of isostatic rebound and eustatic fluctuations in sea level (Ûsaitytë 2001) leading to the Baltic Ice Lake: c. 12500 – 10000 14C BP (Jansen 1995; Andrén

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

63

Fig. 1. Map showing the location of the island Fårö, the locations of the pollen profiles and the extent of forest at the present day.

1999), the Yoldia Sea: c. 10000 – 9500 14C BP (Svensson 1989), the Ancylus Lake: c. 9500 – 8000 14C BP (Bjõrc 1995) and, lastly the Litorina Sea (Persson 1978; Eriksson 1992). The island of Fårö is situated northeast of Gotland (Fig. 1). It is a limestone island on the northwestern rim of a scarp system formed by the mid-Silurian strata of the Baltic geosyncline. The cover of Quaternary deposits on Fårö is thin and very unevenly distributed (Munthe et al. 1936). Over much of the island the bedrock is exposed at the surface and almost all of the overburden has been affected by waves during the pre-stages of the Baltic and transformed into littoral deposits. The island rises to just under 25 m a.s.l. and, over a restricted area of the highest parts a transgressional beach ridge of the Litorina sea is visible. Fårö first emerged from the sea as a number of small separate islands which later, with continued land uplift, joined to form the present island. There are several lakes and fens in the shallow basins which remain in some of which the recent marine influence on the biology is still considerable. Virtually the whole of the northeastern peninsula is covered by aeolian sands of relatively recent origin (Königsson et al. 1995).

64

Juliana Atanassova, Lars-König Königsson and Sheila Hicks

According to Ångström (1958), Gotland belongs to the local-maritime district which also includes Öland and the east coast of Sweden. This type of climate is characterised by positive temperature anomalies during the winter and negative ones during the spring and summer. The amount of precipitation on Gotland is very low, generally less than 450 mm per year. It is also unevenly distributed throughout the year with a pronounced maximum in autumn and winter. Long periods of very low precipitation are common so that the humidity value for the island is that of a sub-arid, dry region (Hesselman 1931). Due to the influence of the Baltic there is a difference in temperature between the coastal areas and the inland parts of the island with the coastal areas being warmer. The prevailing wind direction is from the southwest during the summer and southeast during the winter. Gotland (including the small island of Fårö) belongs to the southern pine forest region of the boreo-nemoral zone (Sjörs 1967). Pinus sylvestris is the dominant tree species today. There are two types of Pinus woods which are unique to Gotland. On calcareous tills the Pinus woods are extremely rich in herbs and Sernander (1894) designated them as Pinus herbidum. Forest clearing by people accompanied by intensive grazing have contributed to the development of this type of vegetation. On rocky ground with only a thin layer of soil Pinus woods rich in Arctostaphylos uva-ursi occur. Picea abies forests also occur, sometimes mixed with pine and in many areas Juniperus communis is common. Deciduous forests are very rare on the island although the old meadow lands which are found on calcareous tills above the Litorina ridge are thought to have devolved from broad-leaved forests. These meadows, which were formerly a characteristic feature of Gotland are now being gradually abandoned after which they become rapidly overgrown. Of the broad-leaved nemoral trees Quercus robur, Tilia cordata and Ulmus carpinifolia are found very sparsely outside the meadow areas, though Fraxinus excelsior has a more widespread distribution (Pettersson 1958). As indicated in the introduction, a very specific landscape type is the alvar. Alvar areas may be defined as landscapes in limestone areas with unevenly distributed, light Quaternary deposits. The bedrock in such areas is thoroughly dissected by karstic fissure systems and the vegetation is characterised by xerothermic floral elements. The alvars are semi-arid, partly because of the edaphic conditions and partly due to the continentality of the climate (Königsson 1992). The vegetation of Fårö is characterised by open pine forests, many of which are still heavily grazed. Some birch, spruce and alder also occur. The field layer is rich in herbs and ruderals. Many of the lake shores are fringed by reeds. The vegetation history of Gotland from the Younger Dryas onwards (11000 – 10000 14C BP) has been described by Påhlsson (1977) on the basis of a very detailed pollen diagram from central Gotland. MATERIAL AND METHODS Three lake sediment profiles were obtained from the island of Fårö, one from each of Dämbaträsk (57° 52’N 19° 8’E): in the extreme south of the island, Norrsund (57° 56’ 30”

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

65

N 19°8’E): centrally in the island but near the north shore and Ajkesträsk (57° 56’N 19° 13’E): in the east (Fig. 1). All sites are less than 5 m a.s.l. (Ajkesträsk 2.5 m, Dämbaträsk 2 m and Norrsund 1.5 m). Together they were expected to provide a pollen record for the island’s history and to allow general regional features to be distinguished from specifically local ones. The cores were taken centrally in the lakes. The stratigraphy of each is as follows: Dämbaträsk 0 - 56 cm 56 - 64 cm 64 - 124 cm 124 - 158 cm 158 - 169 cm 169 - 180 cm 180 - 191 cm Norrsund 0 - 4 cm 4 - 67 cm 67 - 79 cm 79 - 83 cm 83 - 91 cm Ajkesträsk 0 - 11 cm 11 - 32 cm 32 - 55 cm 55 - 58 cm 58 - 88 cm 88 - 110 cm

gyttja with Characeae peat and shell fragments gyttja with abundant Characeae peat particles calcareous gyttja grey gyttja with thin sand layers and with silt and shell fragments dark brown gyttja brownish-black gyttja blackish-brown to black gyttja dark grey-brown gyttja light yellowish-grey calcareous gyttja silty layers and dark gyttja bands dark grey gyttja dark grey-brown gyttja light grey calcareous mud yellowish-grey calcareous gyttja silt yellowish-grey calcareous gyttja dark grey-brown gyttja with silt grey silt with some gyttja

Samples for pollen analysis were taken at 5 cm intervals (in places 2.5 cm). They were prepared by a standard treatment of heating in a dilute alkali solution, sieving and acetolysis and mounting in glycerine (Faegri and Iversen 1989). For each sample at least 1000 pollen grains were counted. Identification was to the lowest possible taxonomic level with reference to Moore et al. (1991), the North European Pollen Flora (Punt 1976-1995) and the collections of pollen reference slides in both Uppsala and Sofia. Pollen nomenclature follows Moore et al. (1991) although some pollen types have been identified to a lower taxonomic level (e. Fraxinus excelsior and Carpinus betulus). The results are presented as percentage pollen diagrams (Figs. 2-4), by means of the Tilia and Tilia-graph programs (Grimm 1992), in which the total pollen sum includes total arboreal pollen plus the pollen of terrestrial herbs but excludes Gramineae and Cyperaceae pollen, pollen of fen and aquatic plants and spores of pteridophytes. The percentage presence of these latter are calculated on the basis of the

66

Juliana Atanassova, Lars-König Königsson and Sheila Hicks

total pollen sum plus each of the respective groups individually. In addition to the pollen, microscopic charcoal particles, dinoflagellate cysts (Marret 1994) and the green algae Pediastrum and Botryococcus were also counted. Their presence, and also the degree of destruction were similarly calculated as a percentage of total pollen plus the relevant individual group. To facilitate the interpretation of the pollen diagrams the pollen and spore taxa are grouped according to their ecological requirements. In assessing the moisture requirements of individual species the growth habitats of individual plants as recognized by Königsson (1968) have been used. The pollen groups delimited in the diagrams (Figs. 2 – 4) comprise the following taxa: 1. Trees, shrubs and dwarf shrubs. A. Trees and bushes which grow on the alvar today or which are present in adjacent areas on Gotland: Salix, Juniperus, Populus, Hippophaë, Betula, Pinus, Corylus, Quercus, Ulmus, Tilia, Fraxinus excelsior type, Carpinus betulus, Acer and Alnus. B. Late immigrating trees or trees which have not immigrated to Gotland: Picea, Fagus, Juglans C. Shrubs and dwarf shrubs 2. Herbs D. Xerophytic/heliophytic herbs E. Other terrestrial herbs F. Cultivated plants plus plants in some way connected to cultural activities (anthropochores and apophytes) G.Varia. Herbs which are not ecologically differentiated with regard to their moisture requirements. In addition this group includes pollen taxa comprising a group of plants with a wide ecological amplitude 3. Locally occurring species H.Gramineae, Cyperaceae, spores of Polypodiaceae, Sphagnum and Equisetum I. Terrestrial spores: Pteridium, Lycopodium and Botrychium J. Fen plants K.Aquatic plants The pollen diagrams in Figs. 5-7 illustrate just groups D – G plus Gramineae (from Group H) and charcoal, but with the cultivated taxa (Group F) illustrated individually. Pollen taxa which occur at very low values and are not illustrated in the diagrams are listed in the Appendix. Only the Dämbaträsk profile has been dated. Three samples of seaweed from a layer 131.5 – 137 cm depth and a small twig from a depth of 112.5 cm were analysed at the Svedberg laboratory in Uppsala with the aim of dating the isolation of Dämbaträsk from the sea. The results of these dates are given in Table 1. They have been published previously together with a description of their treatment and an assessment of what their calibrated age may be (Königsson et al. 1995). The date from the twig (calibrated to AD 1169±69) is regarded as being more reliable than those from the seaweeds. For this reason, the three

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

67

Table 1. Radiocarbon dates. For a more detailed description of the calculation of the calibrated ages see Königsson et al. (1995). Lab. No

Material dated

Sample depth (cm)

Weight (mg)

Ua-4150 Ua-4151 Ua-4152 Ua-4153

twig seaweed seaweed seaweed

112.5 131.5 134.5 137.0

20.9 12.6 30.8 104.0

C age BP

Cal. age AD

855±65 1315±65 1050±65 1550±70

1169±69

14

}

983±145

seaweed dates are averaged to give a calibrated age of AD 983±145 (applying a 150 years reservoir effect). RESULTS The pollen diagram from Dämbaträsk (Fig. 2) has been divided into 3 pollen assemblage zones (PAZs). Their positioning in the profile and pollen characteristics are summarized in Table 2. The radiocarbon dates all fall within PAZ D-2. The other two profiles are also divided into PAZs. In doing this the main features of the regional (coming from the island) and extra regional pollen (groups A- E and G), as far as this is determinable, has been given greater weight than the immediately local pollen taxa (groups F and H-K). On an island as small as Fårö where the distance between the lake profiles in question is only 10 km and 5 km it can be expected that the dominant changes associated with the terrestrial vegetation (and of pollen being transported from the mainland) will be synchronous within the sampling interval employed here. On the basis of this, although only one profile is actually dated and that for only one relatively short interval, the PAZs distinguished in the Norrsund and Ajkesträsk diagrams are correlated with those of Dämbaträsk in Table 2 and assumed to be synchronous. Taking this as a chronology those pollen features indicative of cultivation, which is potentially a more local event (pollen group F), and those associated with the local isolation and development of the individual lake basins (pollen groups H-K), can be compared and contrasted between the three sites. The record at Norrsund is considered to be much shorter than at the other two sites. The regional pollen features characteristic of the PAZs D-1 and A-1 are missing and it is only at the base of the profile that features which could be equated with those of PAZs D-2 and A-2 are seen. This is in keeping with its topographical location. Whereas Dämbaträsk and Ajkesträsk are situated in shallow basins, Norrsund is one of a series of lakes and/or lagoons which occupy a shallow trough cutting across the island from coast to coast This same zonation is applied to the simplified diagrams in Figs. 5-7. In these diagrams it is the pollen taxa which are more likely to reflect the alvar vegetation, grazing and cultivation which are illustrated.

200

th

To (cm ta ) lx e C he rop no hy tic p Ar h te od H m i i a c e rb e s ea s R lia n ia e u t Pl m e hem an x u Pl ta m a g Pl nta o la an go n Po ta c ce l g o o To ygo o m ron lata o t n Ac al o um edi pu a s h t To ille her avi /m a t a t cu j C a l C a n e rre l a r o r t e d e yp e Se rea ultiv As s tri c li a t a Tr ale a ty ted er t l he y iti pe p p rb c e la s s H u o m nt s Av rde typ en um e C a t an ty yp To na pe e t b Ta al v ac r a e U axa ria ae rti c Br ca um a typ G ss e a ic Fi lium ace lip ae Th en a d R lic ula a tr Ap nun um i c To ace ulu t a s G al l e typ ra o c e C m i al yp n ta Po era eae xa l c To ypo ea t d e Pt al t iac er er e Bo idi res ae t u t Ly ryc m rial c h Pe op ium s po re di odi s as um tru c m la D va in of tu l m C age ha l rc late o D cy e s al st s tro ye d gr ai ns

De p

AD 1169

AD 983

200

20 20 40

Calcareous gyttja 60 80 100 20

Gyttja (dark brown)

D

Pi n

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae

40

PAZs

20

C o Q rylu u s U erc lm us Ti us li Fr a a C xin ar us Ac pin e e u xc Al r s b els nu et io ul r s us Sa lix Ju ni pe Po rus p Fa ulu g s Pi us c Vi ea bu M rn yr u R ica m ha C m a n Va llun us c a Er cin ic iu ac m ea ty e pe (u nd iff .)

us

a

AP

Be tu l

P/ N

ib r De a te d pt a h (c ge s m Li ) th ol o A gy

Ca l

68 Juliana Atanassova, Lars-König Königsson and Sheila Hicks

Dambatrask A

40

E

20

Fig. 2. Main pollen diagram Dämbaträsk. 60 80

Gyttja (brown-black) Gyttja (black)

F

B

20

Shells Characeous peat

G

20

C

0

10

20

30

40

50

60

D-3

70

100 80

110 90

120

130

D-2

140

150

160

170

180

190

D-1

20

Sand

H I

20

L

10 0

PAZs

20

30

40

50

60

D-3

70

80

100 90

110

120

130

D-2

140

150

160

170

180

190

D-1

analysed by Juliana Atanassova

20

20

ep th

To (cm t C al x ) he e Ar no rop te p h He mi odi ytic l s a R ian ia cea her u m th e bs Pl ex em an um Pl ta a g To nta o la t g n Ac al o o m ce hi th ed ola To lle er ia ta t a t / C al c an err ma er u d es jo Se ea ltiv As tri r ty c lia a t a p Tr ale ty ted er t l he e p e p yp r b iti la e s C cu nt s an m s t n To a yp ta b a e Ta l v ce r a a G axa ria e al c Fi ium um lip ty R en pe an d Th un ula a c Ap lic ula i tr c To ace um eae t a G al l e r a oc C min al yp e t a Sp era ae xa Pohag cea l n e To ypo um t d Pt al t iac e e e Bo rid rre ae try ium stri al oc sp oc or cu Pe es s di D as in tr o u C fla m ha g r c el oa lat l ec D ys es ts tr o ye d gr ai ns

D th ol

(c m

og

th

20

Gyttja 40 60 80 100 20

Pi n

a

40

PAZs

20

)

C or y Q lu s ue Ti rcu l ia s U lm Fr us ax C i nu ar s p e Ac inu xc er s e ls be io Al tu r nu lu s Sa s lix Ju ni Fa per gu us Pi s ce Vi a bu M rnu yr m ic C a al l Va una cc Er ini ic um ac ea typ e( e un di ff. )

us

Be tu l

AP y /N AP

Li

De p

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae A

40 60

D

Fig. 3. Main pollen diagram Norrsund. E 80

F

B

35

80

G H

20

I

35

80

69

Norrsund

C

0

5

10

15

20

25

30

40

N-3

45

50

55

60

65

70

75

85

N-2

90 100

Silt

L

0

PAZs

10 5

15

20

25

30

40

N-3

45

50

55

60

65

70

75

85

N-2

90

analysed by Juliana Atanassova

20

De pt h To (c m ta lx ) er op Ch hy e tic A nop rte o he di m rb He is ac s lia ia ea e Ru nth m em Pl ex um an Po tag ly o l To gon anc ta um eo A l ot av lata ch he ic To illea r te ula ta a rre re Ce l c u nd s tr re ltiv A s ial Se alia ate ter he c t d ty rb Tr ale ype pla pe s nt s itic s Ca um nn ty p a To b e a ta c Br l v a eae as ria G s ic al a iu c Fi m ea lip e e Ra nd nu ula Th nc al ul Ra ic tr ac e nu um ae Ta nc ra ul To x a us t ta cu y p G l loc m ty e ra a p m Cy ine l tax e p a a Sp era e ha c e Po gn ae ly um To pod ta iac Pt l te ea er rre e Bo idiu s tr tr m ial sp Bo yc h or try ium es oc oc Pe cu di s Di as t no ru f la m ge lla te Ch cy ar st co s al De st ro ye d gr ai ns 20

NA P

40

Clacareous mud 60 80 100 20

Gyttja

D

nu s

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae

40 20 40

E

20

Fig. 4. Main pollen diagram Ajkesträsk. 60 80

F G

(u nd iff.

)

Ajkestrask

Sa l Ju ix n Po ipe p ru Fa ulu s gu s Pi s ce a Vi bu M rn y u Ca rica m l Er lun ic a ac ea e

Co r Q y lu u s Ul erc m u Ti us s li a Fr a Ca xin r u Ac pin s e er us xce Al be ls nu tu ior s lu s

Pi

Be tu la

P/

(c m ) Li th ol og y A

De pt h

70 Juliana Atanassova, Lars-König Königsson and Sheila Hicks A B

20

H

20

20

C

0

5

PAZs

10

15

20 25

30

35

A-3

40

45 50

55

60

65

70

75 80

A-2

85

100 90

105 110 95

A-1

20

Silt

I L

0

5

PAZs

10

15

20

25

30

35

A-3

40

45

50

55

60

65

70

75

80

A-2

85

100

90

105

95

A-1

110

analysed by Juliana Atanassova

20

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

71

Table 2. Pollen assemblage zones (PAZs) delimited for the three profiles and their pollen characteristics. 14C dates

Dämbaträsk

Pinus 60-82%, Betula 5-14%, Juniperus –18%, Xerophytic herbs (Rumex, Pl.lanceolata, Artemisia, Chenopodiaceae) 1-4% Cultivated plants (Secale, Triticum) 1-4% Aquatic plants Pediastrum 10% Pinus 35-57 Betula 10-36% 855±65 Alnus 5-8% BP Thermophilous deciduous trees 1315±65 2-7% BP Xerophytic herbs 1550±70 (Chenopodiaceae, BP Artemisia, Pl.lanceolata, Rumex) 1-4% Pediastrum 10-20% Betula 25-30%, Pinus 30-35%, Alnus 10-14%, Thermophilous deciduous trees 6-7%, Xerophytic herbs (Chenopodiaceae, Artemisia, Pl.lanceolata, Rumex) 5-15% Dinoflagellate cysts 10-15%

pollen zones and their depths

D-3

Ajkesträsk

Pinus 50-80%, Betula 10-30% Picea 1-10%, Alnus 1-12% Xerophytic herbs – 1-2% A-3

79-0 cm

D-2 155-79 cm

pollen zones and their depths

53-0 cm

Norrsund

Pinus 75-90%, Betula 5-15%, Picea 2-8%, Juniperus 2% Xerophytic herbs 1-2%, Cultivated plants 1% N-3

Botryococcus 1-10%

Pediastrum 1-4% Botryococcus 2-15%

Pinus 20-35% Betula 32-35% Alnus 15-20% Thermophilous deciduous trees A-2 5-6% Xerophytic herbs 87-53 cm (Artemisia, Chenopodiaceae) 5-15%

Pinus 50-70% Betula 15-30% Alnus 2-8% Thermophilous deciduous trees 2-5% Xerophytic herbs (Artemisia, Chenopodiaceae) 4%

Pediastrum 1% Pediastrum 2-4% Botryococcus Botryococcus 1-12% 10-30% Betula 25-45%, Pinus 20-35%, Alnus 5-22%, Thermophilous D-1 deciduous trees A-1 2-5% 191-155 cm Xerophyric herbs 110-87 cm (Chenopodiaceae, Artemisia) 5-10% Dinoflagellate cysts 5-18%

pollen zones and their depths

67-0 cm

N-2 90-67 cm

72

Juliana Atanassova, Lars-König Königsson and Sheila Hicks

l rc oa C ha

D

ep

t To h (c ta m ) lx er op

hy tic

he

rb

s

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae

To T o tal ta oth lc e ul r t tiv er Se at r e ed st ca le pl rial an h ts e r b Tr s Hoiticu Av rde m t y C enaum pe e C rea typtyp an li e e To n a ta ab typ l v ac e ar ea G ia e ra m in ea e

Dambatrask (Selected pollen taxa)

PAZs

0 10 20 30

D-3

40 50 60 70 80 90 100 110

D-2

120 130 140 150 160 170

D-1

180 190 200

5

10

15

20 1

1 2 3 4

1 2 3 4

1

1

1

1

1

1 2 3

5

10

5

10

15

analysed by Juliana Atanassova

Fig. 5. Simplified pollen diagram from Dämbaträsk showing selected taxa: groups D (xerophytic/ heliophytic), E (other terrestrial taxa), F (cultivated taxa - these individually), G (total varia), Gramineae (from Group H) and charcoal.

DISCUSSION Fårö (sheep island as its name suggests), is a relatively young island. The isolation of Dämbaträsk from the Baltic is seen at a depth of 115 – 120 cm in the sediment profile at the point where dinoflagellate cysts (the most common species, Lingulodinium machaerophorum, is typically marine) virtually disappear and there is a peak in the fresh water, green alga Pediastrum (Fig. 2). There is also a stratigraphical change at this point from gyttja containing sand to more purely organic gyttja. In an earlier publication this isolation was dated to slightly before AD 1169±69 (the date on the twig - Table 1), i.e. Late Viking Age - Early Medieval time. The isolation process and the transition from salt to brackish and eventually fresh water may have been relatively slow. A time span of 190 radiocarbon years has been calculated for this but note that the error on this calculation is ± 160 years (Königsson et al. 1995). The same isolation feature: the disappearance of dinoflagellate cysts and the appearance and rise to higher values of a fresh water, green alga – in this instance Botryococcus – is seen at Ajkesträsk (Fig. 4) at a depth of 70 – 75 cms (although there is no stratigraphic

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

73

Norrsund (selected pollen taxa)

D

ep

th

To (cm ta ) lx er op hy To tic ta he To l ot rb s ta he Se l cu r te ca ltiv rre Tr le at st ed ria iti pl l h C cum an er er ea typ ts bs C li e an a t To nab ype ta ac l G va ea ra ri e m a in ea e C ha rc oa l

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae

PAZs

0 5 10 15 20 25 30

N-3

35 40 45 50 55 60 65 70 75

N-2

80 85 90 1

2

3

1

1

1

1

1

1

1

1

2

3

10

20

30

analysed by Juliana Atanassova

Fig. 6. Simplified pollen diagram from Norrsund showing selected taxa: groups D (xerophytic/ heliophytic), E (other terrestrial taxa), F (cultivated taxa — these individually), G (total varia), Gramineae (from Group H) and charcoal.

change at this point). At the very base of the Norrsund diagram (Fig. 3), 90 cms depth, this change seems already to have occurred (very low values of dynoflagellate cysts but peaks in both Pediastrum and Botrycoccus) and the preceding salt water stage is not recorded. All the lake sites are at present below 2.5 m altitude, with Norrsund being at the lowest altitude (1.5 m). If the PAZs designated in the three profiles (Figs. 2-4) are taken as chronologically synchronous, then at the time when Dämbaträsk and Ajkesträsk where becoming discrete lake basins, a channel dividing the island in two still existed at Norrsund. Prior to that the island must have been even more fragmented. Small bits of what is now Fårö must, however, have been in existence some 7000 14C years BP since there are traces of the Litorina transgression on its highest elevations nevertheless no more than the last 1500 years or so of the island’s history is reflected in the pollen profiles presented here. This can be deduced both from the date of isolation at Dämbaträsk and from the Picea pollen curve. All the three diagrams from Fårö show

74

Juliana Atanassova, Lars-König Königsson and Sheila Hicks

Ajkestrask (selected pollen taxa)

ria lh er To bs ta lc Se ul ca tiva te Tr le d it i pl c an Ce um ts re ty p a Ca lia e nn ty p Li aba e nu c m ea e To ta lv ar ia

Ch ar co al

in ea e G ra m

To ta lo th er t

De pt h To (c t a m) lx er op hy t

ic

er re st

he rb s

Percentages of total terrestrial pollen excluding Gramineae and Cyperaceae

PAZs

0 5 10 15 20 25

A-3

30 35 40 45 50 55 60 65

A-2

70 75 80 85 90 95

A-1

100 105 110 10

1

2

3

4

5

1

1

1

1

1

1

1

2

3

1

2

3

4

5

10

20

analysed by Juliana Atanassova

Fig. 7. Simplified pollen diagram from Ajkesträsk showing selected taxa: groups D (xerophytic/ heliophytic), E (other terrestrial taxa), F (cultivated taxa — these individually), G (total varia), Gramineae (from Group H) and charcoal.

continuous curves for Picea. Pollen diagrams from the adjacent mainland (Berglund et al. 1996) although showing isolated grains of Picea from 3000 14C years BP, only exhibit continuous curves from 1500 14C years BP. Once the lake basins contained fresh water (from second half of PAZs D-2, A-2 and N-2 until present, shown by the high and then continuing presence of Pediastrum at Dämbaträsk and Botryococcus at Ajkesträsk and Norrsund), the number of aquatic species increases (especially at Dämbaträsk). Myriophyllum spicatum, M. alternifolium, Nuphar, Potamogeton, Nymphaea (Appendix 1a) are all recorded at Dämbaträsk during PAZ D-3. According to Samuelsson (1936) different species of Potamogeton and Myriophyllum spicatum live in brackish to fresh water while Nuphar, Nymphaea and Myriophyllum alternifolium prefer fresh water conditions. The lower parts of the Dämbaträsk and Ajkesträsk profiles (prior to 983±145 cal. AD, see Königsson et al. 1995), contain evidence of the terrestrial vegetation at a time when the lake basins were still connected with the sea and when the basins themselves contained salt

Late Holocene vegetation development on the island of Fårö, Gotland, Sweden

75

– brackish water (PAZs D-1 and A-1 and early part D-2 and A-2). The most important trees in the forest cover during this period were Pinus and Betula. Alnus and Salix were widespread and the thermophilous deciduous forest trees: Quercus, Ulmus, Tilia and Fraxinus were more important than they are today. In the pollen record, Juniperus has rather low percentage values. However, consideration should be given to the fact that Juniperus pollen is sensitive to destruction and the destruction degree, in PAZ D-1 and A-1, is relatively high (Figs. 2 and 4). A more or less open landscape existed as indicated by the high quantity of xerophytic/heliophytic herbs (Group D) – Chenopodiaceae, Artemisia, Helianthemum, Polygonum aviculare, Rumex, different Plantago pollen types and by high values of the Varia group (G). However, the pollen taxa Chenopodiaceae, Gramineae and Artemisia potentially include pollen grains of species growing frequently and spontaneously in the beach area such as Salicornia europaea, Sueda maritima, Salsola kali, Atriplex litoralis, Artemisia maritima, Amophylla arenaria, Elymus arenarius and others. There is also evidence of cultivation during the early time of lake sedimentation, especially in the area of Dämbaträsk, where pollen grains of Triticum-type, Hordeum-type, Secale, Cerealia-type and Cannabaceae were identified. The high values of NAP accompanied by relative high charcoal values during pollen zones D-1 and A-1 could indicate that fire had been used for clearing the land. The pollen diagrams in Figs. 5-7 show that a xerophytic/heleophytic vegetation (which could be correlated with alvar vegetation) existed from the time of isolation of the lakes. Unfortunately many of the really characteristic alvar plant species (Rosén and Borgegård 1999) cannot be separated from other species and/or genera of the same family on the basis of their pollen morphology and so it is not possible to say how many of the ‘terrestrial’ and ‘varia’ taxa in PAZ D-2, N-2 and A-2 represent alvar or cultivated areas. The shapes and behaviour of the curves resemble those of the xerophytic species more closely than those of the cultivated ones in that they are more abundant in D-2, N-2 and A-2 than they are during the later PAZ where cultivated taxa become more important. In her investigation of a comparable island, Stora Karlsö, Eriksson (1992) concluded that the alvar vegetation there resulted from sheep grazing, this pressure converting the original forest to alvar. The same could very well be true of Fårö. The time period during which alvar vegetation is most widespread and cultivation minimal (PAZs 1 and 2) would appear to be from the Viking Age through to the 15th century. At the beginning of PAZ D-3, A-3 and N-3 significant changes in the vegetation occur. There is a clear increase in Pinus pollen and a decrease in the pollen percentages of all other trees. The expanded growth of Juniperus at Dämbaträsk (Fig. 2) and the slight increase in the xerophytic/heliophytic herbs such as Artemisia, Chenopodiaceae, Helianthemum and Plantago lanceolata indicate the existence of more open landscape. The clear increase in Pinus pollen may merely reflect the reduction in the deciduous trees rather than an actual increase in pine forest, because of the way the results are expressed as percentages of total terrestrial pollen (Ranheden 1989). Pine remained one of the most common trees on the island, as it was in the previous periods and as it still is today.

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This change to more open vegetation communities may be connected with drier conditions, but it is more likely that it indicates an opening of the landscape caused by forest clearance. The increase in the curve of cultivated plants (Group F, Figs. 5–7) during PAZ D3, N3 and A3, indicating agrarian activity, strongly supports this. There is a clear difference in intensity between the three sites, cultivation indicators being most abundant in the vicinity of Dämbaträsk where Secale is particularly well represented. Cereal pollen values remain below 1% total pollen at both Norrsund and Ajketräsk. Ajketräsk is located close to the eastern peninsula of the island (Fig. 1) and the peninsula is covered by aeolian sand (see map in Königsson et al. 1995) and supports pine forest at the present day. Therefore, this part of the island may never have been suitable for cultivation. Evidence from Gotland as a whole (Helmfrid 1994) suggests that farming, as it had become established in 13th century, continued in much the same way to mid 17th century with just a few farms being abandoned. In AD1645, Gotland (which until then had been part of Denmark) became part of Sweden. Records from that time on show that the island of Fårö had a one-field system with the arable land scattered and divided into a number of irregular parcels (Helmfrid 1994). Grain was the main crop but cattle farming was the main type of husbandry. This situation continued, with farms being divided into smaller and smaller units until the land reform was finally implemented and the land redivided in 1860’s. However, the population of Gotland, including Fårö, has always been sparse and the level of cultivation low compared with that of the mainland. With the limited number of radiocarbon dates available it is not possible to construct a reliable age-depth chronology. If, however, the isolation at Dämbaträsk at 115 cm depth is taken as c. AD 1200 then, assuming a constant rate of sediment accumulation between that time and the present (which is not necessarily so since the stratigraphy changes at 60 cms depth, suggesting some overgrowing of the lake), then the mid 17th century change with Gotland becoming part of Sweden could be around 46 cms depth and the implemented land reforms of the mid 19th century around 14 cms. On the same basis the PAZ D-2/D3 boundary, at 80 cms depth, would be mid 15th century. A tentative conclusion is that the alvar vegetation, produced as a result of grazing on dry soils, was already in existence in the Viking Age and that cultivation of cereals was also practiced at that time. From 15th century onwards arable farming increased and so did animal husbandry. As a result, grazing pressure increased to such an extent that the landscape became even more open and the only sparse forest that survived was dominated by pine. The distribution of arable farming on the island was determined by edaphic conditions, being concentrated more in the south and west, the poor sandy areas of the northeast being used more for grazing. ACKNOWLEDGEMENTS We would like to thank Kristiina Karjalainen for preparing the maps in Figure 1 and Prof. Björn Berglund for critically reading an earlier version of this manuscript.

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REFERENCES Alm-Kübler K (2001) Holocene environmental change of southern Öland, Sweden. Uppsala dissertations from the Faculty of Science and Technology 28, Acta Univ Uppsaliensis, Uppsala. Andrén T (1990) Till stratigraphy and ice recession in the Bothnian Bay. PhD Thesis. University of Stockholm, Department of Quaternary Research, Report 18. Stockholm. Andrén E (1999) Holocene environmental changes recorded by diatom stratigraphy in the southern Baltic Sea. Ph. D. Thesis. Meddelanden från Stockholms universitets institution for geologi och geokemi, 302, Stockholm. Berglund BE (1979) The deglaciation of southern Sweden 13,500-10,000 BP. Boreas 8: 89-117. Berglund BE, Digerfeldt G, Engelmark R, Gaillard M-J, Karlsson S, Miller U, Risberg J (1996) Sweden. In: Berglund BE, Birks HJB, Ralska-Jasiewiczowa M, Wright HEJr (eds) Palaeoecological events during the last 15 000 years. Regional Syntheses of Palaeoecological Studies of Lakes and Mires in Europe. John Wiley & Sons, Chichester, pp 233-280. Björc S (1995) A review of the history of the Baltic Sea, 13.0-8.0 ka BP. Quatern Intern 27: 19-40. Eriksson A (1992) Natural history of xerotherm vegetation and landscapes on Stora Karlsö, an island in the western Baltic basin, Sweden. Striae 35: 5-78. Faegri K, Iversen J (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester. Grimm EC (1992) Tilia and Tilia-graph: Pollen spreadsheet and graphics programs. Programs and Abstracts, 8th International Palynological Congress, Aix-en-Provence, September 6-12, 1992, p 56. Helmfrid S (ed.) (1994) National Atlas of Sweden, Landscape and settlements. Hesselman H (1931) Om klimatets humiditet i vårt land och dess inverkan pa mark vegetation och skog. Medd frStatens skogfors 26, Stockholm, pp 551-554. Jansen J (1995) A Baltic Ice Lake transgression in the southwestern Baltic: evidence from Fakse Bugt, Denmark. Quatern Intern 27: 59-68 Königsson L-K (1968) The Holocene history of the Great Alvar of Öland. Acta Phytogeogr Suecica 55, Uppsala. Königsson L-K (1992) Preface. In: Natural history of xerotherm vegetation and landscape on Stora Karlsö, an island in the western Baltic basin, Sweden. Striae 35: 5-6. Königsson L-K, Atanassova J, Possnert G (1995) Construction and publication of diversified pollen records – a practical and economic dilemma. Pact 50, 13: 497-507. Marret F (1994) Evolution paleoclimatique et paleohydrologique au Quaternaire terminal. Contribution palynologique (Kystes de Dinoflagelles, pollen et spores). Ph. D. Thesis, L’Universite Bordeaux. Moore P, Webb JA, Collinson ME. (1991) Pollen Analysis. 2nd ed. Blackwell, Oxford. Munthe H, Hede JE, Lundqvist G (1936) Beskrivning till kartbladet Fårö, Sveriges geologiska undersökning. Aa 180. Påhlsson I (1977) A standard pollen diagram from the Lojsta area of central Gotland. Striae 3: 3-41. Persson C (1978) Dateringer av Ancylus- och Litorinatransgressionerna på sodra Gotland. Sverige Geol Unders, pp 745. Pettersson B (1958) Dynamik och konstans i Gotlands flora och vegetation. Acta Phytogeogr Suecica 40.

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Poska A (2001) Human impact on vegetation of coastal Estonia during the Stone Age. Acta Univ Uppsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology. Punt W, Blackmore S, Clarke CG, Hoen PP (1976-1995) The Northwest European Pollen Flora. Elsevier Science, Amsterdam. Ranheden H (1989) Barknåre and Lingnåre human impact and vegetational development in an area of subrecent land uplift. Striae 33: 3-80. Ringberg B (1988) Late Weichselian geology of southernmost Sweden. Boreas 17: 243-263. Rosin E, Borgegard S-O (1999) The open cultural landscape. In: Rydin H, Snoeijd P, Diekmann, M. (eds) Swedish plant geography. Acta Phytogeogr Suecica 84: 113-133. Samuelsson G (1936) Die Verbreitung der hõheren Wasserpflanzen in Nordeuropa. Acta Phytogeogr Suecica VI, Uppsala. Sernander R (1894) Studier över der gotlänska vegetationens utveck lindngshistoria, Thesis. Uppsala. Sjörs H (1967) Nordisk växtgeografiä, Stockholm. Svensson N-O (1989) Late Weichselian and Early Holocene shore displacement in the Central Baltic, based on stratigraphical and morphological records from eastern Småland and Gotland, Sweden. Lundqua Thesis 25, Lund. Ûsaitytë D (2001) Late Quaternary Biostratigraphy of Sediments of the Southeastern Baltic Sea. Comprechensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 604. Acta Univ Uppsalensis, Uppsala. Ångström A (1958) Sveriges klimat, Stockholm.

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APPENDICES Presence of pollen types not illustrated in the diagrams together with the ecological group to which they are assigned.

APPENDIX 1(A) Pollen taxa not included in the pollen diagram Dämbaträsk. Pollen taxon

Group depth [cm]

Juglans Hippophaë Cornus Ribes Centaurea jacea type

B C C C D

Centaurea cyanus

D

Adonis type Campanula

D D

Papaver Sedum Scleranthus Linum usitatissimum Chelidonium

D D D D E

Hypericum Viola Scrophulariaceae Euphorbia

E E E E

99.5 75 158.5 136.5 46.5 135.5 183.5 11.5 18.5 86.5 118 54 99.5 143.5 183.5 7 7 11.5 72.5 39 123.5 138.5 143.5 0.5 188.5 15.5 0.5 15.5

%

Pollen taxon

Group depth [cm]

0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1

Epilobium Geum type Potentilla type

G G G

Succisa

G

Valeriana

G

Cirsium type Litorella

G K

Myriophyllum spicatum M. alternifolium Nymphaea Nuphar Potamogeton

K K K K K

Typha latifolia Spores Equisetum Lycopodium complanatum

J H I

%

72.5 94 3.5 75 84 89 143.5 188.5 168.5 173.5 183.5 128.5 153.5 158.5 22 64.5 30.5 67 11.5 18.5 42.5 86.5 99.5 96

0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.1

64.5 84 138.5

0.1 0.1 0.1

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Juliana Atanassova, Lars-König Königsson and Sheila Hicks

APPENDIX 1(B) Pollen taxa not included in the pollen diagram Norrsund. Pollen taxon

Group

depth [cm]

%

Pollen taxon

Rhamnus Centaurea jacea type Scleranthus Polygonum aviculare Campanula Melampyrum Linum usitatissimum Rosaceae Potentilla type

C D D D D E F G G G

0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.2

Brassicaceae Valeriana Succisa Mentha type Urtica Typha/Sparganium type Spores Botrychium Lycopodium annotinum

Ranunculus type

87 13 62 0.5 81 2 34 0.5 76 81 34 81

Group

depth [cm]

%

G G G G G J

0.5 27 81 34 87 56

0.1 0.1 0.1 0.1 0.1 0.1

I I

7 76 81 90

0.1 0.1 0.1 0.1

Group

depth [cm]

%

94 100 110 83 98 105 6.5 51 83 83 46 56 65.5 98 51 59 59

0.1 0.1 0.1 0.1 0.1 0.4 0.3 0.1 0.1 0.1 0.3 0.2 0.2 0.5 0.1 0.1 0.2

APPENDIX 1(C) Pollen taxa not included in the pollen diagram Ajkesträsk. Group

depth [cm]

%

Pollen taxon

Centaurea jacea type Centaurea cyanus Adonis type Plantago major/media

D D D D

G

Apiaceae

G

D D E

Brassicaceae

G

Scrophulariaceae Melampyrum

E E

Rosaceae Potentilla type

G G

Epilobium Caryophyllaceae

G G

0.2 0.2 0.1 0.4 0.4 0.1 0.2 0.1 0.2 0.2 0.3 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Lamiaceae

Plantago coronopus Linum Euphorbia

103 6.5 76.5 96 105 110 36 94 56 64.5 32 12.5 23 88 105 6.5 41 51 76.5

Potamogeton

K

Myriophyllum alternifolium

K

Pollen taxon

Spassimir Tonkov (ed.) 2003 Can natural habitats be utilised in Aspects a sustainable 81 of Palynologyway? and Palaeoecology

© PENSOFT Publishers Sofia - Moscow

Festschrift in honour of Elissaveta Bozilova, pp. 81-111

Can natural habitats be utilised in a sustainable way? Carl-Adam Hæggström1 and Eeva Hæggström2 1

Department of Ecology and Systematics, Biocenter 3, University of Helsinki, P.O. Box 65, FIN-00014 Helsinki, Finland. E-mail: [email protected] 2 Tornfalksvägen 2/26, FIN-02620 Esbo, Finland

ABSTRACT Two types of natural habitats used by man, namely wooded meadows and coppices are described. These have been utilised for long periods without fertilising. The main products of the wooded meadows are hay and leaf fodder and they could also be grazed. The main products of coppices are thin wood and tan bark. Further, coppices have been used for grazing and some of them also for temporary cereal cultivation. Several points of contact exists between the management of wooded meadows and coppices. In both management systems more or less natural vegetation is in use, although they are man-made. An interesting observation is that the number of species increases considerably when woodland ecosystems are subject to a moderate disturbance compared to untouched woods on one hand and to heavily disturbed vegetation on the other. Differences between wooded meadows and coppices are mainly found in the intensity och frequency of the management. The meadow glades of a wooded meadow were scythed every year and the trees of pollard meadows were pollarded every third to fifth year. Coppicing cycles were longer and coppicing may have been more diversified than the wooded meadow management, especially in coppicing systems where cereal cultivation was included. The Haubergwirtschaft in Siegerland with a combination of agriculture, grazing and a kind of forestry is described. As agriculture and forestry improved during the late 19th and especially the 20th centuries, the traditional use of wooded meadows and coppices ceased almost wholly. KEY WORDS: Coppice – Haubergwirtschaft – Siegerland – Wooded meadow

INTRODUCTION It has been known for long that the productivity of both natural and man-made ecosystems can be improved by adding nutrients, especially nitrogen. Therefore, the production of arable fields, meadows and woods will immediately improve if nitrogen fertilisers are added.

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It has often been said that farmers during the era of natural economy knew, either empirically or only intuitively, how the soil should be treated without loosing its productivity in the long run. This assertion is, however, not valid if facts are looked upon closely. As long as cultivation has gone on, farmers have apparently tried to get the largest possible yield, sometimes with good result, but occasionally with disastrous consequences. TRADITIONAL FARMING IN THE NORDIC COUNTRIES Before the last decades of the 19th century, the arable fields were used for production of cereals, turnip, potatoes, hemp, flax, etc. These crops were produced with the aid of dung. As no commercial fertilisers were available, farmers were more or less wholly dependent on the dung produced by their own domestic animals. In forested areas of the Nordic countries the small arable fields were used each year. Rye and turnip were also produced in temporary fields created through the slash-and-burn technique (Heikinheimo 1915). In the eastern part of mid Sweden and in southwestern Finland, the arable fields were cultivated every second year. Thus they lay in fallow during the years between. In south Sweden and Denmark the most common cultivation regime was two years with different crops and one year in fallow. Practise had shown that the fields could not sustain continuous cultivation if there was a lack of dung. During the fallow year nutrients could accumulate. Areas close to the habitation were mostly fenced. Such fenced areas comprised arable fields, meadows and pastures. The bulk of the winter fodder was gathered from meadows of different kind, such as open and wooded dry and mesic meadows, wet meadows and fen meadows. Fens and reed beds were also used. The importance of meadows is shown by the fact that in areas with arable fields in fallow every second year, the total meadow area was 4-6 times larger than the field area (Hæggström 1983). Thus the meadow area in use each year was actually 8-12 times larger than the field area in cultivation. Swedish 17th and 18th century literature gives good examples of the importance of the meadows. Two translated quotations may illustrate this: – A common proverb says that the meadow is the mother of the field. That is: if the meadow is of good quality and also large, it is possible to keep many animals, the dung of which can be used to fertilise the arable field so that it will be productive. Therefore, it is of utmost importance for the farmer that he strives to attain much and good meadowland. (Rosenhane c. 1660.) – It is indisputable and a generally acknowledged truth that agriculture as a whole relies rather much on meadow management. The quality of arable fields and the farmer’s total economy in general may be concluded from the condition of the meadows of the farm. Much grain and many cattle are the farmer’s greatest treasures, but how can a meagre field produce grain, dung be gathered and the cattle thrive without meadow and suitable fodder? (Norrgreen 1754.)

Can natural habitats be utilised in a sustainable way?

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ECOLOGICAL CRISES An ecological crisis may have arisen due to fast population growth which resulted in a too intesive utilisation of the resources. The rising demand for grain could then result in ploughing meadows to arable fields. Thus the number of animals which could be fed on fodder produced by the rest of the meadows had to be lowered which in turn lead to diminished production of dung needed for fertilising the fields. The yield decreased, more arable fields had to be ploughed in meadows and pastures which further hampered the animal husbandry. The farmer ended up in a vicious circle which could not be broken without totally new methods, such as cultivation of hay in ploughed fields and the use of chemical fertilisers. However, before these methods came in use at the end of the 19th century and on a vast scale only during the latter part of the 20th century, many farmers were forced to leave their farms and move to towns, or emigrate. The situation was especially critical during years of famine. History knows excellent examples of how high cultures deteriorated due to far too intensive use of forests and arable soils (Perlin 1991). This has, however, happened also locally. For instance, in south Scandinavia, the population increase during the 18th century led to a more intensive use of arable fields. Fallow periods were shortened and thus yields diminished. New arable fields were ploughed in meadows and that led to a decrease in fodder for the cattle, fewer cattle and less dung for the fields. On the sandy soils of Scania (the depression of Vomb Depression and the plain of Kristianstad), intensified cultivation during the 18th century triggered sand drift. The arable fields were oversanded and thus destroyed for ever (Emanuelsson et al. 1985). The slash-and-burn cultivation in Finland and parts of Sweden often resulted in deteriorating soils. The reason for this was the short regeneration periods, often only 20-25 years. During the regeneration phase, deciduous trees, such as Alnus incana, Betula pendula, B. pubescens, Populus tremula and Salix spp., invaded the previously burnt spot. Symbiotic Frankia bacteria in the root nodules of grey alder increased the nitrogen content of the soil. Much of the nitrogen, both in the vegetation itself and in the humus, escaped, however, to the atmosphere when the area was burnt. On the other hand, an accumulation of soluble nutrients were mobilised when the trees were felled. This effect is, in fact, very important for fertilising slash-and-burn fields. An other type of ecological crisis occurs when the control of the cultivated land is lost due to population decrease, for instance as a result of disease or war. Seven years of complete depopulation of the Åland Islands during the Great Nordic War in 1714-21 must have been quite detrimental for the agriculture of this archipelago area. During these seven years, arable fields and meadows deteriorated and their recultivation afterwards meant a far greater effort than during normal circumstances. There are also examples of apparently sustainable cultivation systems. We will describe two of them, namely the traditional management of on one hand wooded meadows and on the other coppicing, often combined with temporary cereal production and animal husbandry. In both cases the management was strictly regulated.

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THE CONCEPT WOODED MEADOW The concept wooded meadow was established in Sweden during the 19th century. It was, however, often used both inaccurately and erroneously, because some authors did not realise the real character of the wooded meadows. For instance, Sernander (1892, 1894, 1900, 1901, 1912) was of the opinion that the wooded meadows of Sweden represented natural plant communities which were small remnants of the vast wooded meadows of the Post-Glacial Atlantic time. The vegetation of a wooded meadow consists of two quite different plant communities: patches of open meadow alternating with copses of trees and shrubs (Fig. 1). The copses and meadow glades vary in size and alternate more or less irregularly. Thus a wooded meadow is a vegetation complex of the mosaic complex type (Du Rietz 1932). An area may be called a wooded meadow only if the following two conditions are fulfilled: 1) the trees and shrubs must form the typical mosaic of meadow glades alternating with copses 2) the area must be used for hay.

Fig. 1. A mosaic of trees and shrubs alternating with open meadow glades is a typical feature of wooded meadow. The trees are, e.g. Carpinus orientalis and Malus sp. medium pollards and Quercus dalechampii shredded pollards. – Bulgaria, Stara Planina, Milanovo, 15 May 1991. Figs. 1-10, photo by the author C.-A. Hæggström.

Can natural habitats be utilised in a sustainable way?

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A sharp boundary between a genuine wooded meadow on one hand and wooded pastures and certain coppices on the other, is, however, not always easy to draw. The land use of an area may have altered in the course of time. Grazing, as the only form of management, often preserves the structure and the species richness of a former wooded meadow for decades, although scything has ceased. Such a wooded pasture can easily be changed into a wooded meadow if the traditional management is reintroduced. A wooded meadow copse can comprise only one solitary tree or shrub, or several trees and shrubs together. Deciduous species, such as Acer spp., Alnus glutinosa, Betula pendula, B. pubescens, Carpinus betulus, Corylus avellana, Fagus sylvatica, Fraxinus excelsior, Malus sylvestris, Quercus spp., Salix spp., Tilia spp. and Ulmus spp., are common species of the copses. Juniperus communis is the only common conifer. In the Swedish limestone island of Gotland and in Estonia, pine (Pinus sylvestris) may grow abundantly in the wooded meadows (Romell 1942; Hæggström 2000a). A few spruces (Picea abies) occur as a rule in wooded meadows in Estonia (Hæggström 1995; Kukk and Kull 1997). These trees are used as rain shelter for people if heavy showers occur during hay-making. Spruces were not, however, allowed to grow in, e.g. Alandian and Swedish wooded meadows. The trees and shrubs of the copses contribute to the varying light conditions of the meadow glades. They also make the wooded meadows ‘deep rooted’ (Sjöbeck 1962), which means that there is a continuous flow of nutrients from deeper layers of the soil via the roots of the trees and shrubs to their leaves and further via the litter to the surface layers of the soil. The mosaic structure with copses and glades is a paramount feature of the wooded meadows. The ‘forest edge’ is very well developed and often the whole of a wooded meadow is a complicated ecotone. Especially in the archipelagoes and coastal areas of the Baltic Sea, wooded meadows occur on uneven terrain with wet spots alternating with dry rock outcrops. The soil is often rich in calcium whereas the bedrock may be acid. Thus a mosaic of different edaphic conditions develop. Different light conditions in glades and copses and the varied edaphic conditions result in an often amazing richness in vascular plant species. The wooded meadow management contributes also, perhaps decisively, to the species richness. THREE KINDS OF WOODED MEADOW Three kinds of wooded meadows have been discerned, namely pollard meadows, coppice meadows (Bergendorff and Emanuelsson 1990; Emanuelsson and Bergendorff 1990; Hæggström 1992a) and orchard meadows (Hæggström 1998a). The pollard meadows are characterised by pollards, i.e. pollarded trees (Fig. 2). The main products of pollard meadows are meadow hay and loppings (leafy twigs cut from the trees for fodder). Hazel nuts, crab apples and other fruits, as well as firewood and other wooden products were also gathered. Pollard meadows were regularly grazed by cows and horses some weeks after the haymaking.

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Fig. 2. A pollard meadow with recently repollarded ashes (Fraxinus excelsior). Primula veris abounds in the field layer. – Finland, Åland Islands, Lemland, Nåtö, 25 May 2000.

The typical feature of coppice meadows is trees with multiple stems growing from a common stool (Fig. 3). Trees with single stems are also frequent in these meadows. The coppice meadows resemble coppices; the trees of the coppice meadows grow, however, less densely and their main product is hay, not wooden products. The trees of coppice meadows may be cut with an interval of often some decades, producing stakes, poles, wood for carpentry and firewood, at which time also loppings may be collected. The coppice meadows were also used for grazing, and fruits may have been collected in the same way as in the pollard meadows. Sjöbeck (1932) suggested that orchards have their origin in wooded meadows. As some types of orchards are regularly used also as hay meadows, a kind of wooded meadows that could be called orchard meadows can be discerned (Fig. 4). In these orchard meadows, fruit trees, such as apple and plum trees, are growing scattered or in fairly dense stands (Hæggström 1998a, 1998b). The main products of orchard meadows are fruits and meadow hay. These meadows are also grazed. The different types of wooded meadows are not sharply delimited. For instance, one of the wooded meadows of Nåtö Island in the Åland Islands, SW Finland, has Fraxinus excelsior and Alnus glutinosa pollards intermingled with multiple stem Alnus trees (Hæggström 1983). The orchard meadows of the village of Ribaritsa in the Balkan Mountains in Bulgaria are

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Fig. 3. The typical feature of a coppice meadow are trees with multiple stems growing from a common stool, in this case birches and black alders. The field layer comprises among others the orchid Dactylorhiza sambucina (both the red and yellow coloured morphs) and Primula veris. – Finland, Turku archipelago, Houtskär, Jungfruskär, 4 June 1997.

bordered by, e.g. Corylus shrubs and pollards of Carpinus betulus, Fraxinus excelsior and Tilia cordata (Hæggström 1998a, 1998b). New pollards are created by cutting young trees, the trunk of which are approximately 5 to 15 cm in diameter at breast-height (Hæggström 1983; Mitchell 1989). Thereafter the trees are repollarded regularly, usually in 3 to 5 year intervals. Even shorter intervals of 1 or 2 years occur. Cutting height varies from 1.5 to about 10 metres. The lateral branches of high pollards are usually cut near the trunk, thus forming shredded pollards. Shredded trees have only the lateral branches cut, whereas the top of the tree is left intact (Rackham 1980; Mitchell 1989; Christensen and Rasmussen 1991; Slotte 1992, 1993, 1997, 1999). Several deciduous trees are pollarded. The best leaf fodder is considered to be derived from Ulmus spp. and Fraxinus excelsior. Other commonly pollarded taxa are Acer, Alnus, Betula, Carpinus, Juglans regia, Morus, Populus, Quercus, Salix (especially S. alba and S. caprea), Sorbus and Tilia (branches are also cut for their bast). In the Mediterranean area Melia azedarach, Morus alba, Olea europaea, Platanus orientalis, Tamarix spp. and even Eucalyptus spp. belong to the pollarded tree species. Populus nigra is often only shredded and some of the oak species (Quercus spp.) are chiefly cut into shredded pollards (Hæggström 1998a, 1998b).

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Fig. 4. A hay-stack at the edge of an orchard meadow with plum trees. – Bulgaria, Stara Planina, Teteven, Ribaritsa, 18 July 1996.

Fraxinus excelsior and Ulmus glabra are usually cut into both low and medium pollards and shredded pollards. On flat ground, or on gentle slopes, the pollards grow solitary, or in small stands, forming – together with meadow patches – the irregular mosaic pattern of pollard meadows. On steep mountain slopes pollards usually grow along the banks of narrow meadow terraces (Hæggström 1998a, 1998b). Thus the meadows form gently sloping open-meadow strips delimited by rows of pollards. These meadows are often irrigated. THE ORIGIN OF WOODED MEADOWS The wooded meadows are man-made. The plants of the meadow glades and the copses are wild species, but the mosaic structure of copses and meadow glades is totally dependent on activities, such as clearing, scything and grazing. The use of leaf fodder is older than the use of the use of meadow hay. Leaves of deciduous trees have apparently been used as winter fodder for domestic animals since the Neolithic Age (Rasmussen 1988, 1990a, 1990b, 1991, 1993). During the Neolithic time, people began to live in permanent settlements and keep domestic animals. Cows, oxen, sheep and goats were kept in pens and foddered with leaves of, e.g. Betula, Fraxinus, Tilia

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and Ulmus (Steensberg 1943; Troels-Smith 1953, 1960, 1961; Rasmussen 1990a, 1990b, 1991). Flint saws and flint sickles may have been used for leaf fodder gathering during the Neolithic Age (Sandklef 1934; Steensberg 1943). Even though the origin of wooded meadows seems to be in the leaf fodder gathering, scything is required for the genesis of a genuine wooded meadow. There is no proof of scything during the Neolithic Age, but experiments with flint tools have shown that they could be used to harvest cereals together with their weeds (Steensberg 1943). Thus it is possible to use such tools also for harvesting meadow hay. Further, hay may be collected also by ripping by hand. During the Bronze Age and especially the Iron Age, better metal tools for harvesting both leaf fodder and meadow hay came in use. One prerequisite for wooded meadow management on a larger scale is the supply of suitable tools, particularly scythes of iron. The iron scythe is known from the pre-Roman Iron Age. Therefore, it may be judged on excellent reasons that wooded meadows appeared in the Nordic countries during the Early Iron Age, at the latest. Wooded meadows can have been created in different ways: 1) By mowing seashore meadows along the land uplift shores of the Baltic Sea. Scattered stands of deciduous trees were left in the meadows, which were gradually enlarged as more land emerged out of the sea. 2) By clearing glades in deciduous woods, gradually enlarging the glades and mowing the sward. The clearing could originally have been made to create coppices, and later, when the need for winter fodder became urgent, the coppices were thinned and changed to wooded meadows. 3) By mowing the sward in abandoned cereal fields, which had been established by slashand-burn cultivation, or felling the forests, including mesic spruce forests. Scattered deciduous trees were allowed to grow up. 4) By cultivating fruit trees in meadow land and using the sward for hay. Trees which produced leaf fodder, edible fruits and berries and useful wood for carpentry were favoured. WOODED MEADOW CULTIVATION In the course of time the cultivation of wooded meadows developed its own features. This cultivation usually comprises four yearly phases, namely raking, haymaking, grazing and pollarding (Fig. 5). The management of wooded meadows in different areas shows striking similarities. For detailed descriptions, see Hæggström (1983) and Ekstam et. al. (1988). In the Estonian coppice meadows, grazing and pollarding have not taken place. To the four yearly phases a fifth could be added, namely thinning of thickets, removing of trees and tree stumps, levelling of tussocks and ant-hills. This fifth phase was not performed every year, but only when needed.

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Fig. 5. Haymaking in an combined orchard and pollard meadow. – Bulgaria, Stara Planina, Teteven, Ribaritsa. 18 July 1996.

MAN’S IMPACT ON WOODLAND Man has always used and worked forests. During the Palaeolithic Age, the effect was relatively limited, but as early as in the latter Mesolithic Age, it seems that man shaped forest ecosystems (Rackham 1976). Göransson (1983, 1984, 1986, 1989, 1995, 1996) puts forward an idea that Mesolithic man killed deciduous trees by ringing their bark and using fire in Östergötland, southern Sweden, thus transforming woodland. On the Isle of Lewis in the Outer Hebrides in Scotland, the strong decrease of birch pollen coincides with an increase in among others Calluna and grass pollen and charcoal particles in the soil at about 7900 14C years BP (Bohncke 1988). This can be interpreted as a result of Mesolithic inhabitants destroying the woods by burning. During the Neolithic Age, forests were transformed on an increasing scale with the aid of stone tools and fire, and grazing by domestic animals. The Atlantic heaths began to develop already then, as the woodland was locally eradicated which has been proved for instance in Norway (Kaland 1986a, 1986b, 1987), in Jutland in Denmark (Odgaard 1988) and in Ireland (O’Connell et al. 1988). A similar small scale development took also place in the Baltic area during the late Neolithic Age, e.g. in Blekinge in the southeastern corner of Sweden (Berglund 1966). Wild animals had, of course, influenced forests already before the event of man (Andersson and Appelqvist 1990), although not in such a way that wooded meadows would have occurred.

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Of the total land area of Europe, about 10.5 million square kilometres, approximately 8.9 million square kilometres (about 85 percent) is potential woodland. However, only about 3 million square kilometres (about 29 percent) are now covered by woods, a very small part of which is in near natural state. The vast majority of the woods in Europe of today are culturally modified and influenced by modern forestry. The trees are either of domestic or exotic origin. Some areas are also covered with secondary woodland; they are not in a natural state but are not utilised by modern forestry methods. One kind of such woods are called coppices. COPPICES A coppice resembles a coppice meadow but it is usually much denser (Fig. 6). The main differences between coppices and coppice meadows are in the management rhythm and the main products. Coppices are harvested with few to several years intervals. Their main products are thin wood and tan bark, whereas the coppice meadows are scythed every year for meadow hay. Hay and leaf fodder are usually not gathered at all in coppices, but they are commonly grazed. Several species of deciduous trees are used in coppices. A prerequisite is that the tree is a sprouter, i.e. the vegetative reproduction is effective enough forming either above or below ground shoots from the stump or stool. Besides, the tree must stand repeated cutting.

Fig. 6. A Carpinus orientalis coppice. The area in the front was cut the previous year and a bunch of cut stems is seen at the road bank. – Bulgaria, Stara Planina, Milanovo, 15 May 1991.

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Examples of coppice trees and shrubs are Acer campestre, A. pseudoplatanus, Alnus glutinosa, A. incana, Betula pendula, B. pubescens, Carpinus betulus, C. orientalis, Castanea sativa, Corylus avellana, Crataegus monogyna, Fraxinus excelsior, Ilex aquifolium, Malus sylvestris, Ostrya carpinifolia, Prunus spinosa, Quercus petraea, Q. robur, Salix caprea, Sorbus aria, S. aucuparia, S. torminalis, Tilia cordata, Ulmus carpinifolia, U. glabra and U. laevis. The beech (Fagus sylvatica) has usually a weak ability to sprout. Beech occurs abundantly in coppices only when the cutting cycle is long, or in cases where the beech trees are more vigorous sprouters than usual (Fig. 7). In some coppiced woods scattered trees were left intact to grow into tall trees, standards. These were used as logs for houses, etc. The multiple stems of the coppice stools were cut near the ground. Some sources say that the stems shall be cut at about half a foot (approx. 15 cm) above the ground (e.g. Worsøe 1979), others that the cut shall be done as near the ground as possible (e.g. Tittensor 1970). In Wye Valley at Chepstow, southwestern England, a Tilia wood has trees cut at different heights: from the ground up to three metres (Peterken 1981). Thus low-cut coppice and high-cut coppice alter with ordinary pollards in this area. There are also other high-cut coppices in England (Peterken 1981). The cut surface must be trimmed so that it is smooth (Tittensor 1970; Worsøe 1979). After the stems have been cut, regeneration takes place as a few or several stems grow from the

Fig. 7. A beech (Fagus sylvatica) coppice in the Pyrenees at about 1 600 m altitude. This fairly smooth area was probably used as a temporary cereal field when the coppicing was still going on. – France, Aude, Col du Pradel, 14 October 1990.

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stump or stool. In ordinary coppice management only a few stems were kept, so surplus stems were removed. In Scotland, for instance, some of the stems were cut after a few years to be used as barrel hoops (Tittensor 1970). In Denmark, all but one or two stems were cut after a few years, so that the remaining stems would grow fast (Worsøe 1979). Fagus sylvatica as a weak sprouter was sometimes treated in such a way that only a few stems were cut at each time and thus a stump could bear several stem generations (Peterken 1981). Species which did not stand repeated cutting disappeared, while those which were best adapted to the coppicing cycle were favoured. Thus Fagus sylvatica, as an inferior sprouter compared to birch and oak, disappeared almost totally in the coppices in Siegerland in Germany (Pott 1985). Trees which were preferred could be cultivated (Edlin 1956) and undesirable trees and shrubs could be removed. In the coppices around Loch Lomond in Scotland, the oak was the most valuable tree and by removing birch, hazel and black alder the proportion of oak increased over time (Tittensor 1970). The hazel was cut as a ‘weed’ in oak coppices in Cornwall, southwestern England (Peterken 1981). THE ORIGIN OF COPPICES Coppices are obviously old. Göransson (1989, 1996) suggested that man in Östergötland, southern Sweden, became a real forest farmer already during the mid-Neolithic Age. Through girdling and with the use of fire, the prevalent deciduous woods were changed to cultural biotopes, coppices, in which temporary cereal cultivation occurred between coppice stools and tree stumps. The use of the deciduous trees was included in the management system and the “cereal field was a ‘stubble field’ in the strict sense of the word, a field with deciduous tree stumps” (Göransson 1989; translated from Swedish). The age of these early coppices have been dated in Östergötland to more than 5000 14C years BP. Somewhat younger traces of coppicing have been found in the Somerset Levels in southwestern England, where parallel hazel stems were laid as a track across a wetland (Coles and Orme 1977). The age is, according to 14C datings, between 4460 and 4160 years BP. According to Rackham (1977), the hazel stands were used chiefly for their leaves, and coppicing was a kind of dimension cutting; only those hazel stems were cut that had reached a suitable size. Coppices of much younger age has been found in Hessen in Germany; the oldest are from the Hallstattian, that is from about 700 BC (e.g. Pott 1985). During the Middle Ages a complicated coppice management (Haubergwirtschaft) developed; see below. Coppices have mostly, perhaps always, been created from more or less natural state woodlands with tall and mature trees. If the coppices were used too intensively, through too heavy grazing or too intensive gathering of firewood, they degraded. The coppice trees were to an increasing extent replaced by species that were better suited to stand the grazing pressure and cutting. The coppice trees mostly or wholly disappeared and spiny shrubs, dwarf shrubs, grasses and herbs which are tolerant against grazing replaced them. Much of the Mediterranean vegetation of the macchia, pseudomacchia and garigue (tomillar, phrygana, batha) types are such changed woods (Horvat et al. 1974). Heavy grazing

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and fire are the foremost factors creating and preserving this kind of vegetation. This degradated vegetation was perhaps a coppice before the more grazing tolerant species took over. A kind of coppice like shrubby vegetation, shibljak (Adamović 1899, 1900; Turrill 1929, Horvat et al. 1974) which resembles coppice meadows, occurs in the mountains of the Balkan Peninsula, e.g. in Bulgaria (Hæggström 1992b). Too heavily grazed and burned coppices are changed to juniper rich grass or ling heath in Central och North Europe. If the disturbance becomes very heavy, soil damage through erosion begins to appear. Such erosion damage is commonplace in the Mediterranean area. COPPICES IN EUROPE Coppices occurred chiefly in areas where the demand for wooden articles was great comparing to the supply of timber and other wood products. Bergendorff and Emanuelsson (1982) suggested that the relative demand for wooden products diminishes as the demand for winter fodder increases along a gradient from western Europe via Denmark and Scania to northern Scandinavia. Closely similar gradients are found in the mountains of Central and South Europe: coppices are dominating on lower elevations whereas meadows and pollarding are found higher up.

Fig. 8. A large hazel (Corylus avellana), formerly regularly coppiced for barrel hoops. The height of this shrub is about 8.5 m and the girth at the shrub base 669 cm. The calculated age of the shrub is between 593 and 770 years (cf. Hæggström 2000b). The buildings in the background belong to Nåtö Biological Station. – Finland, Åland Islands, Lemland, Nåtö, 10 April 1998.

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Extensive areas with coppices covered formerly the western, central and southern parts of Europe. Coppices and coppicing are mentioned from, e.g. England and Scotland (Edlin 1956; Tittensor 1970; Rackham 1976, 1980, 1988; Peterken 1981; Collins 1988; Watkins 1990), France (Corvol 1988; Hæggström 1992b), northern Italy (Moreno 1985; Piussi and Stiavelli 1988), Sicily (Garfì and Di Pasquale 1988), the Balkans (Horvat et al. 1974; Bergendorff and Emanuelsson 1982; Emanuelsson and Bergendorff 1990; Hæggström 1992b), Germany (Kraus 1931; Schmithüsen 1934, 1937; Fickeler 1954; Egidi 1981; Pott 1985, 1988b; Brandl 1988) and Denmark (Worsøe 1979, 1980, 1996; Fritzbøger 1988; Petersen 1988). Coppices have occurred only in restricted areas in the Nordic countries outside Denmark. The most prominent coppices in these countries are hazel stands (Fig. 8). These grow often on soil rich in boulders and stones. The hazel stems were cut when the size was suitable for barrel hoops. An example from the Åland Islands may illustrate this. Fishermen from the northeastern archipelago communes of Kumlinge and Brändö began to fish Baltic herring in the Alandian Sea west of the mainland islands at the end of the 19th century. Before they went back to their homesteads they often went ashore on Nåtö Island to get raw material for barrel hoops of an superior quality to the hazels of their own islands (Hæggström 1992, 2000b). The enormous local importance of coppices can be illustrated by the following examples. The total area of coppices in England was 217 000 hectares, which is 30 percent of the total

Fig. 9. A coppice with standards cut the previous year. The shoots of the coppice stools are oneyear-old hazels, ashes and elms, the standards are ash and elm trees. Cut coppice wood lies at the road side. – England, Nottinghamshire, Sherwood Forest, Wellow Park Wood, 3 September 1996.

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woodland area in 1905. Despite change to other kind of forestry the coppice area was still 133 000 hectares or 18 percent of the total woodland area in 1947 (Edlin 1956). Today, the area of coppices is small, but coppicing have resumed in several former coppices (Fig. 9). The situation was nearly the same in Germany. According to Trier (1952), coppices comprised 4.6 percent and coppices with standards 8 percent of all woods in Germany. Of the deciduous stands the corresponding percentages were 16 and 28, respectively. In Schwarzwald 29.5 percent of the total area was covered by coppices in 1780 (Brandl 1988). The percentage diminished to 13.2 during the latter part of the 19th century. During this time coppices covered about ¾ of the total woodland area in Hunsrück on River Mosel in Rheinland-Pfalz; the forest area was unusually high in this region, e.g. 77 percent in Zell (Schmithüsen 1937). The coppice area was still about ¼ of the total woodland area in Rheinland on the left bank of River Rhen (linksrheinische Schiefergebirge) during the 1930s (Schmithüsen 1934). COPPICE PRODUCTS Coppices have been used both for local use and for sale to towns and factories. On the local level, the coppices had to produce raw material for several, perhaps fifteen to twenty different products, such as firewood, charcoal, fencing and building material and wood used for various items in everyday life (Peterken 1981; Collins 1988). In his book on

Fig. 10. A half-timbered house with coppice wood used as wall material between the timber frame. – Bulgaria, the Monastery of Lozen, 16 May 1991.

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woodsmanship in Britain during the era of economy based on domestic production, Seymour (1984) gives a good survey of coppice based products. The most common coppice product was firewood (Horvat et al. 1974). Other products were thin wood suitable for tool handles (Bridgen 1997), fence and hop poles, pales, stakes, faggots (for fences, for reinforcement of river banks and dams, and for a kind of covered drains), hurdles, building (Fig. 10) and thatching materials, etc. In England and Scotland walking sticks and umbrella handles were made mostly of coppice wood. Thin wood and rods for fences were the foremost coppice product in Denmark (Worsøe 1979, 1980, 1996). Timber for houses were taken from coppice standards or from the high grown woods – if there were any. Charcoal could be made from ordinary trees, but coppice wood was chiefly used. Charcoal burning is an old feature in coppices. Charcoal fragments of mostly oak and birch with 521 increment rings have been found in primitive iron smelters in Siegerland, Germany. They belong to the La Tène Culture, i.e. pre-Roman or Celtic Iron Age, dated to a period from about 450 BC to the birth of Christ (Fritz 1952). Charcoal burning and ruthless exploitation of mature trees in Germany led to scarcity of woods useful for charcoal production and thus shortage of charcoal (Schmithüsen 1934). The depletion of mature woods culminated at the end of the 18th and the beginning of the 19th century. Woods were replaced with heathland, impediment and coppices. A parallel development occurred also at about the same time in Småland and the mid Swedish mining district (Bergslagen) as well as in Finland, in the southwestern archipelagoes due to firewood export to Stockholm (Papp 1977) and to tar burning in the Oulu area in MidFinland. An extensive mining activity with primitive iron production flourished in many parts of Europe, e.g. in the Pyrenees (Métailié et al. 1988). This activity used huge amounts of charcoal that was produced in coppices but also by felling all the trees in mixed and conifer woods in the high mountains. Heavy grazing later precluded the regeneration of the trees (Hæggström 1998b). Locally wood was burnt to produce potash for glass and soap fabrication. In Balmaha at Loch Lomond, a pyroligneous acid factory was erected in 1845 using oak as raw material (Tittensor1970). Oak bark was commonly used in tanneries (see below). One of the products of coppices is broom (Cytisus scoparius), used as fodder (young pulses and shoots) for sheep and other domestic animals, as firewood, as litter in cattle pens, for its fibres and for dye (Fickeler 1958). The temporary cereal field is also one of the products of coppices, let be that the true product is grain and straw. According to Collins (1988), the coppice products in England were not the same in the same area during different periods. The products could also vary in neighbouring areas. In areas with little coppices the production was chiefly directed towards the local needs, whereas in areas with plenty of coppices, such as south England and the Midlands, the surplus was mostly used as firewood in the towns and for charcoal in the iron industry (Peterken 1981). About 1/3 of the yearly growth was used for charcoal during the mid 18th century. When

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charcoal was replaced by pit coal the coppices were threatened. Alternative products were then produced which led to an increased quality demand for the raw material. The most important products during this period were coppice wood for fences, hurdles, hop-poles, rakes, tool shafts and other items for agriculture. The industry needed tan bark, barrel hoops, transport crates for glass and pottery, tool shafts, pit props, special charcoal for gunpowder and metallurgy, bobbins for the textile industry and building and roofing material. The local community needed coppice products for everyday use, such as brooms and broomsticks, clogs, baskets, walking sticks and, of course, charcoal and firewood. There are many examples of local specialisation (Collins 1988): hop-poles were produced in southeastern England and southwestern Midlands, brooms and broomsticks in central South England, bobbins, clogs and charcoal for gunpowder in the district of Furness in Lancashire, barrel hoops in western Surrey, south Hampshire, western Berkshire, Herefordshire, Shropshire och Furness, pit props in north England and at the borders of Wales, and transport crates for glass and pottery in nortwest Midlands and later in south England. COPPICING PERIODS The length of the period between two cuttings varied. It was between 10 and 40 years in Denmark, mostly 15 to 25 years (Worsøe 1979). The most common period varied between 5 and 30 years in England, but longer periods, 40 or 50 years have also occurred (Peterken 1981). During the Medieval Age, some coppices were cut at three years intervals. In coppices with several tree species, coppicing cycles of different length may have occurred. According to Collins (1988), the length of the coppicing cycle depends on three factors: the tree species, its rate of growth and the use of the product. Firewood and charcoal cycles in England were normally 12 to 18 years, regardless of species. A trend towards longer cycles was typical for the 16th and 17th centuries, while shorter cycles prevailed during the 18th and 19th centuries. The following coppicing cycles were in common use in southern England during the mid 19th century (Collins 1988): – alder: broom handles 9 years, gunpowder charcoal 12-16 years, clog soles 20-25 years – ash: walking sticks 3-5 years, large hoops 10-12 years, hop poles 12-14 years, tool handles 16-20 years, fence rails 20-25 years – birch: broom handles 8-12 years or 15-20 years – oak: firewood and small uses 10-15 years, bark and pit props 20-30 years – hazel: pottery crates 6-7 years, woven hurdles 7-8 years, hoops 8-10 years – chestnut: hoops 7-8 years, hop poles 11-14 years, pale-fencing 12-14 years. The coppice cycle varied also in other areas, from about 8 or 10 years to nearly 30 years or even more, depending on the product. Cycles of 15 to 25 years at regular coppicing, or up to 40 years at irregular coppicing were common. The coppicing cycles were usually shorter, 4 to 29 years, during the Medieval Age (Pott 1988b). The holly (Quercus ilex) woods of Croatia were cut for firewood approximately every 50th year (Horvat et al. 1974). The

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coppicing cycle of the Haubergwirtschaft of Siegerland in Germany (see below) was 18 to 22 years; 18 years if oak bark was one of the main products (Pott 1985). HAUBERGWIRTSCHAFT: COPPICING MANAGEMENT IN SIEGERLAND One of the most renown, most complicated and best described coppicing systems took place in Siegerland in southern Westphalia about 70-80 km east of Bonn (e.g. Kraus 1931; Fickeler 1954; Pott 1985). Another comprehesively descibed coppicing system was performed in Hunsrück in Rheinland-Pfalz (e.g. Schmithüsen 1934, 1937). Coppicing in Siegerland produced wood for charcoal and oak bark for leather tanning. Besides that the coppices were used as temporary cereal fields and grazing grounds for cattle and sheep. It produced also litter and broom. The wood could be used for firewood, building purposes, etc. In other words, the coppices of Siegerland were areas of real multiple use. This multiple use was united with local industry. Among others, a few small iron works, a leather industry and a glue factory were established in the area using coppice products, and hides and bones of cows grazing the coppices. Coppicing is obviously old in Siegerland. Charcoal fragments of chiefly oak and birch with 5 to 21 increment rings have been found in remnants of primitive iron furnaces from the La Tène culture (Krasa 1948; Fritz 1952). Charcoal of beech was rarely found. This indicates that the climax woods of beech wood were already then replaced by an oak and birch wood. Pollen analysis confirms that the wood had changed in such a way (Pott 1985). Further, only young stems found indicates coppicing. During the Early La Tène Age, the small furnaces were located on valley slopes where air currents blowing down the slopes stood for the blasting effect. During the Late La Tène Age, bellows came in use. Later, during the 12th and 13th centuries, the iron production was moved to the larger brooks in the valleys as water power were harnessed both for the bellows and the hammers (Fickeler 1954). The need for charcoal was huge and coppices were used for charcoal production. The highly developed Haubergwirtschaft in Siegerland originated in the charcoal demand. A forest decree of 1562, and several later decrees, defined how the woods of the villages should be used. All woodland in one commune belonged as a common to one or a few Hauberg cooperatives. There were 220 such cooperatives in Siegerland at the beginning of the 1950s. Each cooperative divided a Hauberg area into a number of plots; at the beginning of the 1950s these were 18-22. This means that the coppicing cycle varied between 18 and 22 years (Fickeler 1954.) The management of a Hauberg area (Haubergwirtschaft) was mainly the following (Kraus 1931; Krasa 1948; Fickeler 1954; Egidi 1981): The birches were cut in early spring in the plot in turn to be coppiced. When the sap of the oaks began to rise and the air temperature was high enough the bark was peeled off the oak stems from the base up to the top (Fig. 11). The approximately 4 metre long bark strips were left hanging from the tops of the oak stems and when dry after one or two weeks they

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Fig. 11. Harvesting oak bark at Eschenbach in Siegerland. The bark strips peeled off the oaks are hanging from the top of the stems. A heap of cut birch stems is seen in the background to the left. – Photo: Arnold in Kraus (1931: Plate IV: 2).

were cut off, made up into bundles and later transported to a tannery. The peeled oaks could now be cut. Occasionally, a few solitary stems were left intact as seed trees. This was especially the case with oak and beech as both produced acorns and nuts which were desirable for fattening pigs during early autumn. The cut trees, especialy the oak, were used to produce charcoal and for firewood, buildings, etc. The areas between the coppice stools were pounded with a heavy hoe during late summer. Litter, twigs and other debris were raked into piles which were burned (Fig. 12). Then the hill slopes were enveloped in a haze of witish blue smoke from the fires which gleamed and glowed during the dark nights. The ash was spread with a shovel in September and the area was seeded with winter rye with short and strong stem. Finally, the soil was ploughed with a light plough designed especially for this work. It was hauled by one or a few cows (Fig. 13). Next year the coppiced area became a temporary rye field with abundant shoots of oak and birch sprouting from the stools. The rye was cut in July. A sickle was used for cutting, because one had to be careful with the growing coppice shoots. The cut rye was bound into sheaves and shocked (Fig. 14). When dry, the sheaves were brought to the farms for treshing. The rye straw was used for thatched roofs.

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Fig. 12. Litter, twigs and other debris are raked into piles and burned in the coppice at Niederdielfen in Siegerland. The trees left are seed trees and future standards. Shoots from several coppice stools are seen in the open area. – Photo: Arnold in Kraus (1931: Plate IV: 1).

After the rye harvest, the plot was left as ‘fallow’ with growing coppice shoots, grass, herbs and broom for a few, often six, years. Broom invaded the plot as some of its seeds in the ground germinated. The broom shrubs were most abundant and at the heigth of their development during the fourth or fifth year after coppicing. The plot was then yellow of broom flowers in May and June. The root nodule bacteria of broom enriched the soil with nitrogen. Shading from the growing trees hampered the broom after the fourth or fifth year and then it began to disappear. However, the importance of broom is illustrated by the fact that about 1/3 of the total coppiced Hauberg always was covered by broom in its best developmental phase. After the ‘fallow’ period, the coppice plot was used for grazing the rest of the 18-22 year cycle. Grazing with sheep could begin in the fourth year after coppicing, with cows and pigs starting during the sixth. As the coppices were not fenced a strict control of the grazing animals was needed. Thus the shepherds and their dogs were very important in the Haubergwirtschaft, a fact that we could observe in the town of Siegen in the form of a bronze monumet comprising a shepherd, his dog and a few cows. A rather similar coppicing management was described from Schwarzwald (Brandl 1988). It was also coppicing combined with agriculture and grazing. The coppices were cut chiefly

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Fig. 13. Ploughing a cut coppice plot in Siegerland with a light plough hauled by a cow. Several shoots have sprouted from the coppice stools. Hill slopes covered with coppices are seen in the background. Recently cut areas are seen behind the man with the plough. – Photo: Arnold in Kraus (1931: Plate V: 1).

Fig. 14. Temporary rye fields on hill slopes near Niederndorf in Siegerland. Shocked rye sheaves are seen on the recently cut coppice plots. A rye field not yet harvested can be seen on the opposite slope to the left with young coppice sprouts seen as dark spots against the light coloured rye. The mid part has been harvested and the coppice shrubs are more prominent. – Photo: Th Kraus in Kraus (1931: Plate I).

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for firewood. After coppicing the soil was burned (it was called Rütti-Brennen) and winter rye, buckwheat and oats, later also potatoes, were cultivated during two to four years. After that the area was grazed during 6-10 years and left to grow broom, hazel, birch, alder and willows. The coppice cycle was here between 10 and 20 years. DISCUSSION The late Swedish author and astronomer Peter Nilson (1995) wrote in his book “Hem till jorden” (Home to the earth; translation from Swedish): “Here in the meadow, among mounds of stones and grass, in the grounds of sheperds and farmers, here we can find some of the deepest roots of our culture.” … “At times I wonder if it is not so that the meadow – the wooded meadow, the Arcadian shepard meadow, the meadow of the old Swedish peasant land – is something of the most beautiful, most remarkable and most ingenious of all that we humans managed to create as long as we took care of the soil on its own conditions, in such a way as it should be taken care of if life shall prosper.” Is Peter Nilson right in his opinion? And was the traditional management of wooded meadows and coppices a use of nature that was lasting in the long run without impoverishing the soil? As already described, large areas of Europe were used for very long as wooded meadows and coppices. They were used in a diversified way for producing those various products that were needed in the traditional economy. The users were therefore forced to look after the condition of the soil so that it produced continuously. Several points of contact exists between the management of wooded meadows and coppices. In both management systems, natural ecosystems influenced and often quite much changed by man were in use. The user decided which trees were allowed to grow both in wooded meadows and coppices. The user also decided the length of the management cycle, that is the intensity and frequence of disturbance in these ecosystems. An interesting observation is that the number of species increases considerably when woodland ecosystems are subject to moderate disturbance compared to untouched woods (“primeval” woods, woods in near natural state) on one hand and to heavily disturbed former woods (cereal fields, lawns) (the intermediate disturbance hypothesis, Connell 1978). Differences between wooded meadows and coppices are mainly found in the intensity och frequency of the management. The meadow glades of a wooded meadow were scythed every year and the trees of pollard meadows were pollarded every third to fifth year. Wooded meadows were often grazed, too. Coppicing cycles were longer and coppicing may have been more diversified than the wooded meadow management, especially in coppicing systems where cereal cultivation was included. For instance, agriculture, grazing and a kind of forestry were combined in an ingenious way in the Haubergwirtschaft in Siegerland. The main differences between wooded meadow management and coppicing on one hand and ordinary agriculture on the other are that the soil is ploughed and fertilised in the latter. In coppice cycles with temporary cereal cultivation a light surface ploughing took

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place, but it cannot be compared to modern ploughs which turns the soil upside down. Another difference is the vegetation, which is multilayered and very diverse in wooded meadows and coppices compared to the single layer monocultures of cereal fields where weeds also are eradicated with herbicides. Hay fields may have several species, but they are still poor in species compared to wooded meadows and coppices. Grazed hay fields are – in conformity with mown hay fields – ploughed and usually seeded with a few suitable fodder plants. Wooded pastures, on the other hand, resemble wooded meadows; their soil is undisturbed and rich in natural species. Many wooded meadows have changed into wooded pastures when only grazed. Coppices resemble young woods with ordinary forestry. They are both regularly harvested, but the management in the coppices occurs perhaps more on the terms of nature. Especially modern forestry, with clear cutting, ploughing, reforesting with monocultures of trees, often of foreign origin, fertilising and using chemical brushkillers, stands far from the much more gentle treatment in coppicing. Wooded meadows and woods resemble each others in the fact that there are trees in both and many of the field layer plants are the same. However, the tendency towards monocultures in forestry is not in line with the abundance of different trees and shrubs in wooded meadows. The mosaic pattern of wooded meadows and in a way in coppices, too, supports a wealth of different organisms. Heliophilic and sciadophilic species can live side by side. Old pollards harbour mosses, lichens, other fungi and evertebrates of different kind than younger trees. Birds nesting in hollows are abundant in landscapes with old pollards. Scything of the meadow glades favours annual plants and plants with low growth. The balance between well managed and mismanaged wooded meadows and coppices is subtle and many of the users were probably well avare of the fact that overexploitation led sooner or later to lower production. The use of nature today is very different from that in olden days. In Europe of today, rather few persons are self-supporting. The modern largescale agriculture depends on subsidies, both money and different chemicals, so that the yield can be maximised. Often the energy input per hectare is larger than the return. Such an agriculture cannot be sustainable in the long run. In former days, there was a lack of mineral nutrients which could be supplied only to a moderate level by dunging the arable fields. Therefore, as much as possible of the animal feces were taken care of and used as dung. It is a paradox today that there is an enormous surplus of animal dung in areas where cattle and pigs are reared, such as The Netherlands and Denmark. Still artificial fertilisers are used in these dung surplus areas. The same problem, although on a smaller scale, occurs in Finland, too. There is a surplus of dung in MidFinland where animal production dominates, while in the southwestern part of the country, with the best cereal fields, hardly any dung is locally available. The animal farms ‘import’ fodder for direct consumtion by the cattle and beside that they also ‘import’ fertilisers to improve grazing grounds and hay fields. However, the surplus of dung is not ‘exported’, which leads to an eutrophication problem of the watercourses. Part of the nitrogen in the

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dung is changed into ammonium which is evaporated to the atmosphere and then adding to the air-borne nitrogen load. Coppicing declined at about the same time as wooded meadow management practically disappeared. The coppice wood products could be made much more efficiently and cheaper in modern factories, or in tropical countries. Import of cheap timber from the Tropics to Europe has largely replaced the domestic coppice products. Coppicing has, however, resumed in, e.g. Britain. Hurdles, wooden frames for buildings and charcoal are among products available on the market. Is there any idea in going back to – or try to preserve – some kind of old fashioned use of natural ecosystems? Alternative farming is already supported and this is a growing sector, although it is a more laborious way of producing food and at least in the beginning the yields are smaller than in intensive farming systems. An interesting permaculture experiment was started in Australia by Mollison (1994). There were more than 140 permaculture institutes in more than 50 countries at the turn of the millennium. In permaculture several crops are cultivated according to as ecological principles as possible. The crops are harvested one after another and perennial crops are preferred to annual. Domestic plants are also preferred. The permaculture system shall be self supporting and the use of artificial fertilisers, herbicides and pesticids is excluded. One idea is to get a maximum yield on a minimum of space. Small gardens and even flowerbeds and flowerpots can produce food in towns. No area is allowed to be bare, which is important in countries with erosion problems. Such a cultivation system with trees, shrubs and smaller crop plants in a mosaic pattern resembles in a way wooded meadows and coppices. REFERENCES Adamović L (1899) Die Vegetationsformationen Ostserbiens. In: Engler A (publ) Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 26: 124-218. Adamović L (1900) Die mediterranen Elemente der zerbischen Flora. In: Engler A (publ) Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 27: 351-389. Andersson L, Appelqvist T (1990) Istidens stora växtätare utformade de nemorala och boreonemorala ekosystemen. En hypotes med konsekvenser för naturvården. Svensk Botanisk Tidskrift 84: 355368 (In Swedish with English abstract). Bergendorff C, Emanuelsson U (1982) Skottskogen – en försummad del av vårt kulturlandskap. Svensk Botanisk Tidskrift 76: 91-100 (In Swedish with English abstract). Bergendorff C, Emanuelsson U ([1990]) Den skånska stubbskottängen [The Scanian coppice meadow]. Nordisk Bygd 4:14-19. Esbjerg. Berglund BE (1966) Late-Quaternary vegetation in eastern Blekinge, southeastern Sweden. A pollen-analytical study. II. Post-Glacial time. Opera Botanica 12 (2): 1-190. Bohncke SJP (1988) Vegetation and habitation history of the Callanish area, Isle of Lewis, Scotland. In: Birks HH, Birks HJB, Kaland PE, Moe D (eds) The cultural landscape – past, present and future. Cambridge Univ Press, pp 445-461.

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Spassimir Tonkov (ed.) 2003 history in northern Estonia during the Holocene based pollenand ...Palaeoecology 113 Aspects on of Palynology Festschrift in honour of Elissaveta Bozilova, pp. 113-126

Vegetation history in northern Estonia during the Holocene based on pollen diagrams from small kettlehole and lake sediments Tiiu Koff * and Mihkel Kangur Institute of Ecology, Tallinn Pedagogical University, Kevade 2, 10137 Tallinn, Estonia * E-mail: [email protected]

ABSTRACT A small kettlehole and Lake Linajärv, two sites of different basin size lying close together, were used to study forest development in northern Estonia during the Holocene. Other sites from the same region were used for comparison. Good correlation between the studied sites and good correspondence with palaeoclimatic reconstructions for Northern Europe demonstrate that the main driving force of the vegetation development during the Holocene has been climate. On the local scale as shown by the pollen data from the kettlehole, the hydrological regime has also been of great importance. KEY WORDS: Pollen analysis – Macrofossil analysis – Vegetation history – Holocene – Estonia

INTRODUCTION The vegetation history in Estonia has been described on a broad scale since the late 1920s when P. Thomson, student of L. von Post, published his paper (Thomson 1929). Since then hundreds of pollen diagrams have been made by various researchers (Ilves and Mäemets 1987; Pirrus et al. 1987; Koff 1994, 1997; Veski 1998). Most of them are generally interpreted as a record of the vegetation of the region, on a scale of tens of kilometres. Theoretical and empirical results show that the source area of pollen is correlated with the size of the sediment basin (Jacobson and Bradshaw 1981). Sites can therefore be chosen to gain the desired level of spatial resolution in palaeoecological studies. The challenge is to identify the regional pollen signal of the past and separate it from the local pollen inputs to reconstruct the local vegetation change of the past. Some attempts have been made also in Estonia by studying sediments from small mires to find the local peculiarities in the vegetation history depending on the role of the temporal distribution of radiation falling on deep kettleholes and differences in hydrological regime (Punning et

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al. 1995). Also relationships between the spatial scale of landscape development and values of pollen influx to lake and bog sediments have been studied. The data obtained reveal that in the case of lakes less than 200 m in diameter, the pollen influx values show essential changes. With the expansion of bogs and lakes, as well as with the destruction of forest by fire or human activities, the openness of the landscape increased, which led to a greater contribution of the long-distance transported pollen component (Punning and Koff 1997; Koff et al. 2000). Identifying and interpreting the local pollen signals requires care, because all sedimentary basins contain pollen derived from both local and regional sources. Early estimates of pollen-transport distances concluded that most of the pollen in small forest hollows is produced by plants growing only 20-30 m away (Anderson 1970; Bradshaw 1981), where as more recent studies suggest that at least 50-60% of the total pollen originates from beyond 50-100 m from the forest-hollow basin (Sugita 1994; Calcote 1995). Information gained later from different models (Prentice 1985; Sugita 1994, 1998) for pollen distribution offers new insights, useful for the reinterpretation of old diagrams and comparison of pollen diagrams from sites with different basin sizes. Parshall and Calcote (2001) demonstrated that pollen assemblages from forest-hollow sediments or closed-canopy sites can be used to identify stand-scale forest composition (within 50 m). Supplementary data from macrofossil studies would improve the interpretation of the vegetation on the stand scale. Recent stratigraphic macrofossil studies have usually been made in conjunction with pollen analysis, utilising the complementarity of the two techniques. Macrofossils are less readily dispersed than most types of anemophilous pollen (Birks and Birks 1980; Birks 2001). This has the advantage that macrofossils tend to present the local flora and vegetation and thus provide a more precise localisation and definition of past vegetation (Kullman 1998). For example if a macrofossil was found of a species with abundant wind-dispersed pollen it may be concluded that the species (e.g. Betula, Pinus, Alnus) was growing in the vicinity and that the pollen was not only derived by long-distance transport. In this paper we present pollen data of two sites: Lake Linajärv and small kettlehole. The kettlehole can be considered a stand-scale site (sensu Bradshaw 1988), as its size is 20×30 m and it has a limited pollen source-area being situated under a closed canopy. The area around these study sites, the Viitna kame field, has been thoroughly studied. The lakelevel changes and most features of the vegetation history are well described for Lake Linajärv (Punning et al. in press) as well as for the pollen section from Lake Pikkjärv located close to the former (Saarse et al. 1998). Organic matter and pollen records dated by radiocarbon and radiolead indicate a water-level rise in both lakes during the early Holocene (c. 10000– 8000 BP). A regression followed around 7500 BP and several transgressions occurred during the later half of the Holocene, c. 6500 and 3000 BP. Human impact during the last centuries has caused short-term lake-level fluctuations and accelerated sediment accumulation in the lakes. Some attempts have been made to investigate the land-use history around Lake Kahala 28 km to the north of the Viitna area (Poska and Saarse 1999). This enables some comparison on a larger regional scale of northern Estonia.

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STUDY AREA The small kettlehole and Lake Linajärv (59o40´ N, 25o45´ E) are situated in the Viitna kame field, a region of low-relief and gently rolling glaciated topography on the northwestern slope of the Pandivere Upland in northern Estonia (Fig. 1). The distance between the two sites is 0.6 km. Beside kames and eskers this area has glaciokarstic hollows, some of which are lakes or are filled with peat deposits. The vegetation around the study sites is determined by various podzols which are the dominating soils. Forest covers 90% of the territory around the lakes, the remaining 10% is under buildings, roads and beaches. 87% of the forest is occupied by Pinus sylvestris, 8% by Picea abies, and 4% by Betula pendula. Pinus and Picea grow mainly on elevations. Birch and other deciduous trees are growing mainly on lake shores and in depressions between eskers and kames.

Table 1. Data on the small kettlehole and Lake Linajärv. Characteristics Surface area, ha Width, m Length, m Max. water depth, m Max. thickness of sediments, m Age of basal lacustrine sediments, BP Number of 14C dates

Fig. 1. Location of the study area and map showing the coring sites in Lake Linajärv (Li1), the small kettlehole (KH1) and nearby Lake Pikkjärv studied earlier by Saarse et al. (1992).

Kettlehole

Linajärv

0.06 20 30 -

3.8 180 390 6.7

3.75

9.6

10000 4

9600 5

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Detailed investigations were performed in the small kettlehole (20×30 m) situated on the western shore of Lake Pikkjärv. The kettlehole is separated from the lake by a radial steep-sloped esker (Fig. 1). At present some birch and spruce trees are growing in the kettlehole. Sphagnum angustifolium and Polytrichum commune form the surface moss layer. Herbs Carex sp., Trientalis europaea and Maianthemum bifolium occur, and some Vaccinium myrtillus shrubs can be found. The kettlehole is surrounded by pine forest. The vegetation around Lake Linajärv consists mainly of pine, which dominates on the poor sandy soils. According to the classification of Estonian vegetation site types (Paal 1997) this kind of forest belongs to the Vaccinium-vitis idea and Oxalis-Vaccinium myrtillus dry boreal forest type. Birch (Betula pendula) and alder (Alnus glutinosa) are growing on lake shores or in valleys between hummocks. Lake Linajärv is a closed seepage lake (Table 1) with a small catchment underlain by limno- and fluvioglacial sediments. Steep-sloped eskers surround the lake from the west and south. On the east a terraced fluvioglacial plain borders the lake and in the north is a small paludified area. MATERIALS AND METHODS Sampling and lithology of sediments For sediment coring in the small kettlehole Russian type peat sampler was used. The maximum thickness of the sediments (3.75 m) in the kettlehole occurred in the centre of the hollow (Fig. 2). The sediments consist mainly of minerotrophic peat, with layers of Carex, Phragmites, and Sphagnum peat and various transitions between these types. Quite often also

Fig. 2. Cross-section of the small kettlehole and lithology of the sediments (KH1) (1 - CarexSphagnum peat; 2 - Carex peat; 3 - Phragmites peat; 4 - Phragmites wood peat; 5 - Drepanocladus peat).

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wood remains of birch, alder, and spruce are found. The peat is more humified in the lower layers and there is a layer of well decomposed alder peat between 1.40 and 1.96 cm. The sediments were studied also in two other cores near the northern and southern edges of the hollow (Fig. 2). At a distance of 4 m from the northern edge the sediment layer is 2.1 m thick and it consists mainly of Carex and Phragmites peat. The southern side with a gentler slope has a 1.5 m thick sediment layer formed mainly by wood and Carex peat. Sediment coring in Lake Linajärv was performed from the ice. The upper layers of lake sediments of the deepest part of the lake were sampled using a modified Livingstone-Vallentyne piston corer (diameter 7 cm). Sampling of the surface sediments in these anoxic environments was complicated due to their unconsolidated nature. Therefore we used a freeze-core technique for the collection of undisturbed cores of surface sediment layers from 60 to 180 cm. The upper parts of the sediment core from Lake Linajärv consist of colloidal, highly organic dark gyttja. Downward the gyttja becomes more compact. The lower, more compact, sediments from 170 cm below the sediment surface down to the mineral bottom was sampled with a Russian peat sampler. The lithology of the cores was recorded in the field. Before analysis samples were stored in a refrigerator. The sediments 280–520 cm depth have a decrease in the water content to 80-90% and a increase in mineral matter up to 10-20%. An outstanding characteristic of the sediments below depth 520 cm is the occurrence of varved sediments. Pollen and macrofossil analysis Samples for pollen analysis were boiled in 10% KOH and treated with the standard method of acetolysis (Moore and Webb 1978). In general, at least 500 arboreal pollen (AP) grains were determined under the microscope. Pollen percentages were calculated using the sum of terrestrial pollen grains (AP) and non-arboreal pollen grains (NAP). Spores and pollen of aquatics were also counted. The pollen diagrams were made using Tilia software (Grimm 1990). Plant macrofossils were analysed from the small kettlehole. For this purpose 5-10 cm thick samples from the same core as for pollen analysis were used. The sediment was placed in a sieve with a mesh diameter of c. 0.25 mm and rinsed with a gentle spray of tap water from a shower head. The residue was placed on a glass plate and studied under the microscope at a magnification of 50 times or occasionally 250 times. For determination various atlases were used (Dombrovskaja et al. 1969; Katz et al. 1977; Grosse-Brauckmann 1972, 1992). The results are presented in a relative scale of occurrence: 1 - rare; 2 - occasional; 3 - frequent; 4 - very frequent; 5 - abundant. RESULTS Chronology Bulk samples from the small kettlehole (Table 2) were radiocarbon dated using the standard decay-counting technique (Punning and Rajamäe 1993). On the basal medium sized sand layer

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Table 2. Radiocarbon datings from sediments from Lake Linajärv (Li1) and the small kettlehole (KH1). Depth from sediment surface, cm

14

C age, years BP

Lab. No.

Material dated

Core Li1 (Lake Linajärv) 240 440 650 720

885±70 4085±100 7925±160 9000±115

Ua-16576 Ua-16577 Ua-16578 Ua-16579

Spruce needle Pine bark Pine bark Pine needle

Core KH1 (kettlehole) 102-107 238-242 280-285 368-372

3700±50 7020±70 7710±60 9070±100

Tln-557 Tln-554 Tln-553 Tln-555

Phragmites peat Phragmites-Hypnum peat Phragmites-Hypnum peat Drepanocladus peat

lies Drepanocladus peat, dated at a depth of 3.68–3.72 cm to 9070±100 BP (Tln-555). The other dated samples are mainly minerotrophic peat. The sedimentation rate was 0.06 cm/yr during the first half of the Holocene and it decreased to 0.03 cm/yr during the last 3700 years. The Lake Linajärv core was AMS radiocarbon dated on macrofossils in the Uppsala University (Table 2). At the beginning of the Holocene (before 9000 BP) the sedimentation rate was high (up to 0.3 cm/yr), falling thereafter considerably (0.05-0.06 cm/yr) from 9000 to 1000 BP. The sedimentation rate was again high (up to 0.27 cm/yr) also during the last 900-700 years. As we have good radiocarbon dating from the small kettlehole as well as from Lake Linajärv, we will present for better comparison both pollen diagrams on an age scale of uncalibrated radiocarbon years BP. This enables us to correlate our data also with investigations made earlier and with the stratigraphical scheme of the Holocene deposits in Estonia (Raukas et al. 1995). The timing of the chronozones follows Mangerud et al. (1974). Pollen and macrofossil data from the kettlehole Before 9000 years BP during the Preboreal chronozone Betula pollen dominates constituting up to 80% and Pinus reaches up to 20% (Fig. 3). Among the NAP Cyperaceae pollen has high percentages (up to 40%), but there is very little evidence of Carex or Eriophorum vaginatum plant macroremains in the peat. Herb pollen such as Poaceae, Rosaceae, Compositae and Chenopodiaceae indicates that the forest was open, so that pollen could be dispersed far from their source. Alnus and Picea pollen are represented by very low quantities, a few macrofossils show that these species had grown in this small hollow. During the Boreal Betula pollen percentages decreased to 40% around 8500 BP (Fig. 3). This was mainly due to the increase in Pinus pollen. The first pine macrofossils date from around 8000 BP. During 9000–8000 BP Picea pollen was represented only sporadically, but macrofossils occurred in low values almost continuously. Alnus pollen was slightly increasing,

Fig. 3. Pollen and macrofossils diagram from small kettelhole (KH1). The results of macrofossil analysis are presented as solid bars in a relative scale of occurrence: 1 - rare; 2 - occasional; 3 - frequent; 4 - very frequent; 5 – abundant. Percentages of pollen data are based on the sum of arboreal pollen (AP) and terrestrial non-arboreal pollen (NAP). Zonation is given according to the stratigraphical scheme of the Holocene sediments in Estonia (Raukas et al. 1985). PB - Preboreal (10000–9000 BP); BO - Boreal (9000–8000 BP); AT - Atlantic (8000– 5000 BP); SB - Subboreal (5000–2500 BP); SA - Subatlantic (2500–0 BP).

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and around 8000 BP this taxon is present as macroremains. Herb pollen is scarce in this period, although the peat itself is formed mainly by Carex and Eriophorum vaginatum. Sphagnum occurs both as macofossils and as spores. At the beginning of the Atlantic 8000 BP Ulmus and Corylus pollen appears and some decrease in Betula pollen occurs. The presence of herb pollen such as Artemisia and Compositae suggests again a more open landscape. The period 7500–3500 BP is characterised by high percentages of Alnus pollen (up to 30%) and macrofossils. Also Corylus was growing in this hollow as is shown by the presence of hazelnuts at depths 2.36 cm and 1.6 cm. Its pollen constituted up to 10%. Betula was represented by lower pollen percentages (30%) than earlier but with a continuous presence of macroremains. Picea has a continuous pollen curve (1-2%) and macroremains. An abrupt increase in Picea pollen started form 5500 BP. At the same time Ulmus and Tilia pollen had values around 10% and Quercus did not exceed 3%. Menyanthes trifoliata macroremains are present together with Equisetum fluviatile. From Pteridophyta spores the majority most likely belongs to Thelypteris palustris as indicated by their presence in macrofossils. At the end of the Atlantic and the beginning of Subboreal around 5000 BP a decrease in Alnus, Corylus, Ulmus, Quercus and Tilia pollen started. Simultaneously an increase occurred in Picea pollen followed by macrofossils. The first maximum of Picea pollen was 4000 BP Alnus pollen showed a decreasing tendency, and there were no macroremains after 3500 BP Pinus pollen began to increase around 2500 BP reaching 60%. A small decrease occurred in the Subatlantic around 1500 BP. Carex and Eriophorum vaginatum still had a large share in the peat formation, but very low values in pollen percentages. Sphagnum spores and macroremains were both present. Pollen data of Lake Linajärv During the Preboreal, around 9500 BP, Betula pollen is dominating with up to 60–99% (Fig. 4). This indicates that most of the Viitna kame field was covered with Betula forest. The relatively high percentage of herb pollen (Poaceae and Artemisia) suggests that the forest was sparse, so that light requiring plants were able to grow under the trees. Around 9200 BP Ulmus and Alnus appeared in the study area, and Pteridophyta became more common. As nutrient-poor sandy soils prevail in the Viitna area these species probably occupied shores of water bodies. The forests on the kame field had grown denser, as only single herb pollen grains were found. Betula was most likely still the dominant tree, as the pollen still comprise around 50% also during the Boreal (9000–8000 BP). Although Pinus became more widely spread, its pollen remains below 30%. Alnus pollen has approximately the same percentage (~20%). Ulmus pollen stays below 10%. Also very few scattered Picea pollen was found. At the beginning of the Atlantic, 8000 BP (Fig. 4), Betula began to lose its importance in the forests of the Viitna kame field while Pinus obviously increased gradually. At the same time Tilia appears in the kame field, although pollen is still below 5%. On nutrient-poor dry soils Pinus can be expected to be much more competitive than broad-leaved species. At the same time the decrease in Betula pollen continues. Betula grew most likely in sites richer in

Fig. 4. Pollen diagram from Lake Linajärv core Li1. Percentages calculated on the sum of arboreal pollen (AP) and terrestrial non-arboreal pollen (NAP). Zonation is given according to the stratigraphical scheme of the Holocene sediments in Estonia (Raukas et al. 1985). PB Preboreal (10000–9000 BP); BO - Boreal (9000–8000 BP); AT - Atlantic (8000–5000 BP); SB - Subboreal (5000–2500 BP); SA - Subatlantic (2500–0 BP).

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moisture and nutrients; however, there it has to compete with Alnus as well as other broadleaved species such as Tilia and Ulmus, which are occupying increasingly larger areas. By 7000 BP Betula pollen has fallen below 30%. It stays at this level for the following 2000 years, after which Pinus pollen the percentages fall again below that of Betula. However, pollen of broad-leaved trees increases, and Alnus and Ulmus pollen reach their maximum levels. Quercus and Corylus pollen increases. Also single pollen grains of Poaceae were found. From 5500 BP onward Picea pollen increases drastically (Fig. 4). While in earlier sediments only a few pollen grains of spruce were detected, by the beginning of the Subboreal spruce pollen quickly increases to 10% and around 4000 BP it attains a maximum of 25%. Simultaneously pollen of broad-leaved trees shows some decrease. The greatest decrease can be observed in Betula, which falls as low as 10%. From then on Betula pollen stays lower than Picea. Alnus and Corylus pollen has also decreased. After such drastic changes in the proportions of pollen Betula pollen shows a slow increase, but it is lower than Pinus, as it is today. At first also the percentage of Picea pollen increases but since 3000 BP it begins to fall again. Also the levels of pollen of other broad-leaved trees start to decrease. At the beginning of the Subatlantic Pinus becomes increasingly more dominant in the study area while broad-leaved trees lose their importance. Only Betula is capable of competing to some extent with Pinus. An especially marked rise in Pinus pollen occurs around 2500 BP when Alnus, Corylus and Tilia pollen show drastic decreases. Also other broad-leaved trees except Betula continue diminishing trends. Picea pollen is also decreasing slowly. Poaceae pollen is relatively higher than before, which indicates increased openness of the area during that period. By about 1000 BP pollen of broad-leaved trees has practically disappeared, and only a few grains of Corylus, Quercus and Tilia can be found. At the beginning of the period the amounts of Betula and Pinus pollen are practically equal, but later Betula pollen falls rapidly to 20% and remains at this level until today, where as Pinus pollen increases. Picea pollen is stable and stays at 15% during the whole period. During the last 1000 years the share of herb and shrub pollen has increased, which indicates that the landscape around Lake Linajärv has become more open than before. Also the Sphagnum spores have increased significantly. DISCUSSION Comparison of the two pollen diagrams shed new light on the vegetation history on different scales. In fact very similar events occurred simultaneously in the two diagrams, although there are also some differences. Both diagrams fit well with the main biotic changes reconstructed in Scandinavia (Birks 1986) and the Holocene pollen assemblage zones established for Estonia (Raukas et al. 1995). The vegetation was very uniform around 9000 BP when birch was the dominant tree. The woodland was most probably semi-open and park-like with scattered trees, or it consisted of groves of trees interspersed with openings before 9000 BP. At that stage of vegetation history the major factor affecting the development and composition of the forest over the next few millennia was the order of arrival of tree species migrating northwards, during

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which period the main differences appear, showing the heterogeneous character of vegetation. Several tree species arrived after 9000 BP. Early immigrants were pioneers, able to germinate under conditions of high light intensity. One of the first taxa was Alnus. This tree is known as a nitrogen-fixer, and the resulting increase in nitrogen in the soil is a necessary condition for the growth of other species. In Lake Linajärv Alnus and Ulmus pollen were present since 9200 BP. In the small kettlehole Alnus also found favorable conditions around 9000 BP, but for Ulmus this occurred 8000 BP. In the other sites of northern Estonia Ulmus migrated around 8500 BP and its spread was very rapid and even (Saarse et al. 1998; Poska and Saarse 1999). Picea pollen was present in Lake Linajärv and also in other pollen diagrams from northern Estonia rather sporadically and in low values (1-2%) already between 9000 and 8000 BP. The same values of Picea pollen were found also in the sediments of the small kettlehole. Macroremains in the peat sediment support its actual growing there. Saarse et al. (1999) pointed to some confusion in connection with a macrofossil find of spruce in the Teosaare profile in South Estonia dated 8495±85 BP (Ilves et al. 1974), which is 1700 years before the rational limit of spruce pollen in the same profile. The same situation was observed in the small kettlehole in Viitna where spruce macroremains were found some thousands of years before the actual increase of Picea pollen in the same profile. In Sweden Kullman (1995) dated subfossil Picea wood and found that spruce grew there more than 2000 years prior to inferences from pollen data. This raises the question about the interpretation of the low pollen content in the other sites from northern Estonia. Picea is known as a low pollen producer in northern Finland (Hicks 1999). Was it only long-distance transported pollen or is it possible that some spruce trees were growing there already earlier but producing pollen in low quantities? Further empirical studies together with the use of simulation models are needed to answer these questions. The synchronicity of the increase of Picea pollen in the kettlehole, Lake Linajärv and all other sites around 5500 BP and the first maximum of Picea (up to 20-25%) around 4000 BP are also noteworthy findings. Corylus arrived into the small kettlehole and Lake Linajärv between 8000 and 7000 BP. It appears in very low pollen values (1-2%) around 8000 BP and increases then rapidly to 10% around 6500 BP. Andersen (1970) has noticed that Corylus presents special problems, as this species may constitute an understorey in some cases and may form a canopy in other cases. It is evident that hazel was growing in the kettlehole at least 6500 BP, as proven by nuts in the sediments from that time. The next arrival into surroundings of Lake Linajärv and other sites of northern Estonia was Tilia around 7000 BP. In the small kettlehole Tilia pollen was found some 500 years later. The first appearance of Quercus pollen in Lake Kahala was already at 7000 BP (Poska and Saarse 1999), in Lake Linajärv and the small kettlehole around 6000 BP but only in very low values of 1-2%. Interpretation of macrofossil data from the small kettlehole should give information about changes in the vegetation on very local scale. The obtained data demonstrate that there exist certain taxa that are present almost continuously over the profile, such as various Carex species,

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Equisetum fluviatile and Eriophorum vaginatum. Therefore, it can be concluded that the minerotrophic fen existed in the forest hollow during the entire Holocene. The presence of some macroremains in a delimited provides more detailed information about the hydrological regime. For example, Menyanthes trifoliata, which is characteristic for high water-level conditions, was found only in sediments from 7000 to 3500 BP together with Thelypteris palustris, Equisetum fluviatile, various Carex species and Alnus. At the present time such a plant composition is characteristic of minerotrophic swamp-forest with stagnant water (Paal 1997). This indicates high humidity and is in good correlation with reconstructions of water-level fluctuations in Lake Linajärv (Punning et al. in press). Maximum water levels and amplitudes of fluctuations were reached in the first half of the Holocene when the sediment surface was lower. So the mean depth of the lake around 9500–9000 BP was 8 m and reached up to 9 m at 8000 BP. Then the lake level stabilised, but the depth of the lake decreased continuously in the course of infilling with sediments. The lake level was at its lowest (2–3 m) about 1000 BP. CONCLUSIONS Comparison of the pollen data from two sites lying close together in similar vegetation and landscape areas but of different basin size demonstrated some similarity in the behaviour of the main pollen taxa. The order of arrival of different tree pollen to northern Estonia during the Holocene was: Betula, Pinus, Alnus, Ulmus, Corylus, Tilia and Quercus. Picea was present in low pollen values since the early Holocene, and increased almost synchronously in both sites at 5500 BP. At least 6000 BP the pollen of the main forest-forming species were represented in the studied sites. As our pollen data show, the long-term climatic changes in the catchment of Lake Linajärv are in good correspondence with palaeoclimatic reconstructions for Northern Europe (Chambers 1993), and the good correlation between the studied sites of different basin size suggests that the main driving force of vegetation development has been climate. Pollen and macrofossil data from the kettlehole reveal that the hydrological regime has been of great importance as well. ACKNOWLEDGEMENTS We are grateful to Prof. Elissaveta Bozilova for her cheerfully sharing of knowledge on vegetation history at different steps of our palynological investigations. The research was supported by the Estonian Science Foundation Grant No. 4133. The authors thank Prof. J.-M. Punning for valuable comments on an earlier draft of the manuscript. REFERENCES Andersen STh (1970) The relative pollen productivity and pollen representation of North European trees, and correction factors for tree pollen spectra. Geological Survey of Denmark II, Series 96, pp 1-99.

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Birks HJB (1986) Late Quaternary biotic changes in terrestrial and lacustrine environments, with particular reference to north-west Europe. In: Berglund BE (ed) Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley & Sons, Chichester, pp 3-65. Birks HH (2001) Plant macrofossils. In: Smol JP, Birks HJB, Last WM (eds) Tracking Environmental Change Using Lake Sediments Vol. 3. Terrestrial, Algal, and Siliceous Indicators. Kluwer Academic Publ, pp 49-74. Birks HH, Birks HJB (2000) Future uses of pollen analysis must include plant macrofossils. J Biogeogr 27: 31-35. Bradshaw RH (1981) Modern pollen-representation factors for woods in Southeast England. J Ecol 69: 45-70. Bradshaw RH (1988) Spatially precise studies of forest dynamics. In: Huntley B and Webb T III (eds) Vegetation History. Kluwer Academic Publ, pp 725-751. Calcote R (1995) Pollen source area and pollen productivity: evidence from forest hollows. J Ecol 83: 591-602. Chambers FM (ed) (1993) Climate change and human impact on the landscape. Chapman and Hall, London. Dombrovskaja AV, Koreneva MM, Tjuremnov SN (1959) Atlas of plant remains found in peat, Moscow (In Russian). Grimm EC (1990) Tilia and Tilia-graph PC spreadsheet and graphics software for pollen data. INQUA, Working Group on Data-Handling Methods, Newsletter 4: 5-7. Grosse-Brauckmann G (1972) Über pflanzliche Makrofossilien mitteleuropäische Torfe I. Gewebreste krautiger Pflanzen und ihre Merkmale. Telma 2: 19-55. Grosse-Brauckmann G, Streitz B (1992) Pflanzliche Makrofossilien mitteleuropäischer Torfe III. Früchte, Samen und einige Gewebe. Telma 22: 53-102. Hicks S (2001) The use of annual arboreal pollen deposition values for delimiting tree-lines in the landscape and exploring models of pollen dispersal. Rev Palaeobot Palynol 117: 1-29. Ilves E, Liiva A, Punning J-M (1974 Radiocarbon dating in the Quaternary geology and archaeology of Estonia. Akademija Nauk ESSR, Tallinn (In Russian). Ilves E, Mäemets H (1987) Results of radiocarbon and palynological analyses of coastal deposits of lakes Tuuljärv and Vaskna. In: Raukas A, Saarse L (eds) Paleohydrology of the temperate zone. III. Mires. Tallinn, Valgus, pp 108-130. Jacobson GL, Bradshaw RHW (1981) The selection of sites for paleovegetational studies. Quat Res 16: 80-96. Katz NJ, Katz SV, Skobejeva EI (1977) Atlas of plant remains in peat. Nedra, Moscow (In Russian). Koff T (1994) The development of vegetation. In: Punning J-M (ed.), The influence of natural and anthropogenic factors on the development of landscapes. The results of a comprehensive study in NE Estonia. Institute of Ecology, Publication 2, Tallinn, pp 24-57. Koff T (1997) Der Einfluss der Entwicklung eines Hochmoores auf die Ausbildung der Pollenspektren am Beispiel des Nigula-Hochmoores (SW-Estland). Telma 27: 75-90. Koff T, Punning J-M, Kangur M (2000) Impact of forest disturbance on the pollen influx in lake sediments during the last century. Rev Palaeobot Palynol 111: 19-29.

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Kullman L (1995) New and firm evidence for Mid-Holocene appearance of Picea abies in the Scandes Mountains, Sweden. J Ecol 83: 439-447. Kullman L (1998) The occurrence of thermophilous trees in the Scandes Mountains during the early Holocene: evidence for a diverse tree flora from macroscopic remains. J Ecol 86: 421-428. Moore P, Webb JA (1978) An Illustrated Guide to Pollen Analysis. Hodder and Stoughton, London. Paal J (1997) Classification of Estonian vegetation site types. Ministry of Environment and UNEP, Tallinn. Parshall T, Calcote R (2001) Effect of pollen from regional vegetation on stand-scale forest reconstruction. Holocene 11: 81-87. Pirrus R, Rõuk M, Liiva A (1987) Geology and stratigraphy of the reference site of Lake Raigastvere in Saadjärv drumlin field. In: Raukas A, Saarse L (eds) Paleohydrology of the temperate zone. II. Lakes . Valgus, Tallinn, pp 101-122. Poska A, Saarse L (1999) Holocene vegetation and land-use history in the environs of Lake Kahala, northern Estonia. Veget Hist Archaeobot 8: 185-197. Prentice C (1985) Pollen representation, source area, and basin size: towards a unified theory of pollen analysis. Quat Res 23: 76-86. Punning J-M, Koff T (1997) The landscape factor in the formation of pollen records in lake sediments. J Paleolimn 18: 33-44. Punning J-M, Koff T, Ilomets M, Jõgi J (1995) The relative influence of local, extra-local, and regional factors on the organic sedimentation in the Vällamäe kettle-hole, Estonia. Boreas 24: 68-80. Punning J-M, Rajamäe R (1993) Radiocarbon dating organic detritus: implications for studying ice sheet dynamics. Radiocarbon 35: 449-455. Punning J-M, Kangur M, Koff T, Possnert G (in press) Holocene lake-level changes and their reflection in the paleolimnological records of two lakes in northern Estonia. J Paleolimn. Raukas A, Saarse, L, Veski S (1995) A new version of the Holocene stratigraphy in Estonia. Proceed Estonian Acad Sci, Geology 44: 201-210. Saarse L, Poska A, Kaup E, Heinsalu A (1998) Holocene environmental events in the Viitna area, North Estonia. Proceed Estonian Acad Sci, Geology 47: 31-44. Saarse L, Poska A, Veski S (1999) Spread of Alnus and Picea in Estonia. Proceed Estonian Acad Sci, Geology 48: 170-186. Sugita S (1994) Pollen representation of vegetation in Quaternary sediments: theory and method in patchy vegetation. J Ecol 82: 881-897. Sugita S (1998) Modelling pollen representation of vegetation. In: Gaillard MJ, Berglund BE, Frenzel, B, Huckriede U (eds.) Quantification of land surface cleared of forests during the Holocene - modern pollen/vegetation/landscape relationships as an aid to the interpretation of fossil pollen data. Paläoklimaforschung 27: 1-16. Thomson P (1929) Die regionale Entwickelungsgeschichte der Wälder Estlands. Publ Geol Inst Univ Tartu 19: 1-87. Veski S (1998) Vegetation history, human impact and palaeogeography of West Estonia. Pollen analytical studies of lake and bog sediments. Striae 38: 1-119.

© PENSOFT Publishers Late-glacial Sofia - Moscow

Spassimir Tonkov (ed.) 2003 and Early-Holocene Dry Climates from the Balkan ... Palaeoecology 127 AspectsPeninsula of Palynology and Festschrift in honour of Elissaveta Bozilova, pp. 127-136

Late-glacial and early-Holocene dry climates from the Balkan peninsula to Southern Siberia Herbert E. Wright, Jr.1*, Brigitta Ammann2, Ivanka Stefanova1, Juliana Atanassova3, Nino Margalitadze4, Lucia Wick2 and Tatiana Blyakharchuk5 Limnological Research Center, 220 Pillsbury Hall, University of Minnesota, Minneapolis MN 55455, USA. *E-mail: [email protected] 2 Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland 3 Laboratory of Palynology, Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria 4 Institute of Botany, Georgian Academy of Sciences, Kodjory Road 1, 380007 Tbilisi, Georgia 5 Tomsk State University, Scientific Research Institute of Biology and Biophysics, Lenina 36, 634050 Tomsk, Russia 1

ABSTRACT Whereas afforestation of much of western and central Europe began early in the lateglacial, when climatic conditions were relatively humid, farther east it did not occur until well into the Holocene because of the drier climate. For the Younger Dryas interval, for example, oxygen isotope records in Switzerland indicate a response to low atmospheric temperature, whereas in eastern Turkey and western Iran they indicate dry conditions. For the early Holocene, the pollen sequence near the modern treeline in the Pirin Mountains of southwestern Bulgaria shows that the late-glacial steppe continued well into the Holocene even as the forest expanded at lower elevations. Perhaps because of dry climatic conditions, the modern conifer forests at high elevations did not develop until the mid-Holocene. Cores from the western segment of the Black Sea also suggest persistence of steppe on the east-Bulgarian plains until at least 7000 14C yr BP. East of the Black Sea in the Caucasus Minor a similar sequence is apparent, although the dates are less certain. At Lake Van in eastern Turkey and Lake Zeribar in western Iran the early-Holocene pollen record indicates that the late-glacial steppe continued in the early Holocene while oak and pistacchio gradually expanded. In the Altai Mountains of southern Siberia the modern conifer forest was delayed in development by the persistence of steppe in the early Holocene. The dry climatic conditions implied by these lateglacial isotope and early-Holocene pollen records in the continental interior is consistent with the paleoclimatic model simulations that indicate higher summer temperatures related to higher

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summer insolation. These areas are too far inland to have been affected by the enhanced monsoonal rainfall that is found closer to the sources of atmospheric moisture. KEY WORDS: Pirin Mountains – Black Sea – Lake Van – Georgia – Altai Mountains – Climatic changes – Early Holocene – Aridity – Afforestation

INTRODUCTION Climatic belts in the modern world are clearly delineated, although of course short-term changes caused by such factors as the intensity of ENSO and the Arctic Oscillation create substantial variability in the characteristics and boundaries of these belts at this time. The modern vegetation belts are also well established, but the short-term climatic variability is difficult to detect in lacustrine pollen records, although some events like the Little Ice Age and the Medieval Warm Period are suggested in certain areas. During the last glacial period and in the early Holocene the major factors controlling the climate were substantially different from today in certain parts of the globe, for example the effects of the continental ice sheets on the general atmospheric circulation, and the temperature and moisture levels related to variations in seasonal insolation caused by Earth/Sun orbital variations. The interaction of these two forcing factors was especially critical in the middle latitudes of the Northern Hemisphere, for at this time the North American ice sheet still had an effect on the global circulation, and summer insolation was at its maximum. The complexities meant that the climatic belts were not simply shifted in latitude but were modified as well. At the

Fig. 1. Map indicating the sites: GE Gerzensee (603 m asl, Switzerland), PI Pirin mountains (Lake Dalgoto 2310 m asl, Bulgaria), BS Black Sea (-1400 m bsl, Bulgaria ), GO Gomnis Tba (1850 m asl, Georgia), VA Lake Van (1648 m asl, Turkey), ZE Lake Zeribar (1300 m asl, Iran), UZ Uzun Kol (1985 m asl, Russia).

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same time the vegetational belts were also not simply shifted in toto, but rather the individual taxa followed the complex climatic changes suitable for their distribution, resulting in associations that are different from pre-existing or modern ones. The present paper attempts to trace the vegetational changes in an area extending from Central Europe and the Balkan Peninsula to southwestern Siberia for the time centering on 10000 radiocarbon years ago to examine the evidence for dry climatic conditions in the late-glacial and early Holocene and to postulate the reasons for the changes. The sites considered are on the Swiss Plateau, in the Pirin Mountains and the Black Sea coast of Bulgaria, the Taurus-Zagros ranges of Turkey and Iran, the Caucasus Minor of eastern Georgia, and the Altai Mountains of southwestern Siberia (Fig. 1). LATE-GLACIAL Conditions during the late-glacial provide a starting point, for the climatic fluctuations at this time are strong in the North Atlantic region and are recorded as far east as the Taurus-Zagros ranges. In western and central Europe the Bølling-Allerød warm phase and the Younger Dryas cold phase are represented by at least partial afforestation by birch, juniper and pine followed by return to either treeless conditions in Northwest Europe or to more open woodland (e.g. Gerzensee, Wick 2000), the temperature changes for the Younger Dryas are quantified in that region by a strong decrease in δ18O values in authigenic lacustrine carbonates, indicating cooler atmospheric temperatures similar in direction and magnitude to those recorded in the Greenland ice cores (Fig. 2). The magnitude of the decrease during the Younger Dryas is greatest in the British Isles close to the Atlantic source of moisture (Ahlberg et al. 1996) and is more subdued inland in southern Germany (von Grafenstein et al.1999) and Switzerland (von Grafenstein et al. 2000), just as the oxygen-isotope values in modern rainfall decrease from west to east because of progressive precipitation, which removes the heavier isotope (IAEA/WMO 1998). In these regions the decrease in δ18O values for the Younger Dryas interval reflects low atmospheric temperatures, with no modification by excessive lake-water evaporation, which is the other major process that affects the isotope values. In the continental interior to the east in the Taurus-Zagros Mountains at both Lake Van and Lake Zeribar the direction of the change in δ18O is an increase rather than a decrease. Even though the climate there was cold, as indicated by the evidence for glaciation, it was also very dry, as shown at Van by the increase in magnesium/calcium ratios in the carbonate sediment, reflecting an increase in dissolved solids as a result of enhanced evaporation of the lake water, a process that preferentially removes molecules with the lighter isotopes, so that the result was an increase in δ18O values. (Wick et al. 2003). In intermediate areas between Switzerland and eastern Turkey the isotope values should have intermediate values. The Pirin Mountains of the Balkan Peninsula are in such an intermediate location. But the area consists mostly of crystalline rock, so the lake sediments lack the calcareous sediment necessary for isotopic analysis. The Younger Dryas interval is

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Fig. 2. Timing of the afforestation at the seven sites as expressed by the pollen-percentage curves of arboreal and non-arboreal pollen (AP and NAP). Fig 2a. The three sites with oxygen-isotope curves.

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Fig 2b. The four sites without oxygen isotope studies. The time scales are GRIP age BP at Gerzensee, varve years BP at Lake Van, and uncalibrated radiocarbon years BP at the other five sites. The horizontal line marks the beginning of the Holocene. It is omitted from Gomnis Tba because of the dating uncertainty. Afforestation started at the Swiss site of Gerzensee at the beginning of the Bølling (about 14500 cal. or 12700 uncal. yr BP), but at the eastern sites it was not fully developed until well after the beginning of the Holocene.

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clearly represented there by the increase of Artemisia pollen and other indications of mountain steppe (Atanassova and Stefanova, in press). Such a vegetation type can be attributed to both cold and dry conditions, so the independent evidence provided by isotope analysis could make the distinction. That is, if δ18O fell to more negative values during this interval, low air temperatures would be favored as the explanation, and if the values rose evaporation would be implied. The increased evaporation could also result in lowered lake levels, which could be detected by appropriate lake-sediment investigations. EARLY HOLOCENE Balkan Peninsula The early Holocene of western Europe is marked by the rapid expansion of temperate deciduous trees from refuges south of the Alps. Although low lake levels in southern Scandinavia at this time suggest higher evaporation (Digerfeldt 1972), the dominant forest cover elsewhere implies temperate climatic conditions. In the western Mediterranean region, including northern Africa, lake levels were high, and rivers in the southern Alps were more vigorous (Magny et al. 2002). The greater rainfall then can be attributed to enhanced precipitation of the African monsoon caused by increased summer insolation. Farther inland in southeastern Europe and the Near East in the early Holocene more arid conditions prevailed. In the eastern Mediterranean region lake levels were low (Harrison and Digerfeldt 1993). In the Pirin Mountains of the southwestern Bulgaria at elevations just above the modern tree line (2300 m), high pollen values of Artemisia and other nonarboreal types continued from the late-glacial until at least 8500 14C BP, producing a mountain steppe (e.g. Stefanova and Ammann 2003). Increasing pollen percentages of oak and other temperate trees in the early Holocene probably did not reflect stands of local trees at this high elevation but rather were a result of long-distance transport of pollen from lower elevations up to a landscape of low local pollen production and dispersal. Macrofossils of oak were found at an elevation of 1900 m, or 800 m above its modern range limit, with birch there at the tree line. The higher limit of oak implies warmer climatic conditions. But because the upper treeline is controlled primarily by temperature, the fact that the tree line then was 400 m lower than today implies a cooler climate instead. The situation is complicated by the delayed expansion of conifers, which are better adapted to high elevations than oak and the temperate deciduous trees. When the conifers did arrive, they filled the 400 m of alpine zone and depressed the belt of temperate trees an additional 800 m. The reason for the slow expansion of conifers may have been insufficient moisture. The moisture factor for the early Holocene in the Pirin Mountains is not so easy to evaluate from independent local evidence. The addition of grasses to the Artemisia-chenopod association suggests that humidity increased after the late-glacial. However, the persistence of steppe in contrast to forest suggests either cold or dry conditions. That the climate was certainly warmer is indicated by the increased elevation of oak, as mentioned above. And

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paleoclimatic modeling indicates warmer summer temperatures during the time of increased summer insolation (Kutzbach et al. 1993). On the other hand, evidence for conditions too dry for conifers comes from the distribution of confers today in the Near East. Pine is present in most of the forested areas of Turkey, and spruce even exists on the humid slopes facing the Black Sea in the north. But as precipitation decreases to the east across Anatolia, pine diminishes in importance, and in the Zagros Mountains of western Iran pine is absent, and the forest there is almost entirely of oak, with pistachio especially at the lower tree line. In fact still farther east oak diminishes in extent, and the lower and upper tree lines merge. These relations imply that pine and other conifers may not have expanded in the early Holocene in the Pirin Mountains because conditions were too dry. In conclusion, the pollen record in the Pirin Mountains of southwestern Bulgaria suggests that the cold and dry climatic conditions of the late-glacial turned warmer and slightly moister in the early Holocene, allowing the persistence of steppe and inhibiting the spread of the conifers that today make up the highest forest zone. Black Sea In cores from the western depths of the Black Sea have yielded a pollen sequence that indicates that a late-glacial steppic vegetation continued until about 7 ka 14C BP, when the temperate trees arrived more than 2000 years later than in western Europe (Atanassova 1995). Surface samples of Black Sea sediment indicate that the dominant pollen source was the Bulgarian plains to the west as a result of westerly winds The inferred early-Holocene dry conditions are consistent with the history of the Black Sea itself. At this time the level of the Black Sea was about 20 m lower than today (Chepalyga 1984) because of dry climatic conditions, but it was a flow-through freshwater body, with salinity at about 3-7% (modern salinity 18%). As global sea-level rose at the end of continental glaciation the outlet was reversed and the dry littoral shelves of the basin were flooded by Mediterranean water about 7500 14C yr BP, perhaps catastrophically (Ryan 1997; Ryan and Pitman 1998). Conditions necessary for the early-Holocene formation of sapropel in the Mediterranean Sea resulted from the stratification of the water column caused by the increased inflow of fresh water from the Nile River catchment, attributed to enhanced summer insolation. The increased precipitation did not penetrate far inland from the eastern Mediterranean region, i.e not to the Black Sea area, and that such summer rains as did occur were a result of Atlantic storm systems tracking along the Mediterranean sea (Rohling and Hilgen 1991). These relations are consistent with the pollen evidence for dry early-Holocene conditions in the Black Sea area. Caucasus Minor East of the Black Sea in the Caucasus Minor (Trialeti Mountains), pollen studies of a core from the lake shore at Gomnis Tba indicate that steppic vegetation prevailed in the

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early Holocene until afforestation in the mid Holocene (Maraglitadze 1995). This points to dry conditions even at 1850 m asl where orographic rains could be expected. Only shortly before 5000 BP the reforestation begins with Corylus, Carpinus caucasicus and later Ulmus, Quercus, Fagus orientalis. Taurus-Zagros Mountains Still farther east in the Taurus/Zagros Mountains pollen studies at 5 sites (Zeribar, Mirabad, and Urmia in western Iran and Van and Sogutlu in eastern Turkey) show that the late-glacial Artemisia-chenopod assemblage of the Younger Dryas was succeeded in the early Holocene by dominant grasses, indicating that the climate had become more temperate and more humid (van Zeist and Bottema 1991; Wick et al. 2003; Stevens et al. 2002). But it was still drier than subsequently, for oak and pistachio increased in the mid-Holocene and dominate today. Isotope analyses of lacustrine carbonates at Lake Zeribar and Lake Van in the early Holocene have lower values of δ18O. These cannot be attributed to mean annual temperatures, because the pollen evidence suggests the reverse. Instead they may reflect a shift from summer to winter precipitation, for winter values are lower than summer because of the lower temperature (Stevens et al. 2001). At Van steppic vegetation dominated by grasses and high fire frequencies combined with a rapidly rising lake level (as indicated by decreasing δ18O values and Mg/Ca ratios) point to increased winter precipitation and rather dry weather conditions during the growing seasons (Wick et al. 2003). Such a seasonality factor might explain the glacial-age existence of high lake levels in central Anatolia at the same time as pollen evidence indicates an Artemisia-chenopod semi-desert, for winter precipitation can maintain lake levels but does not particularly favor plant growth. Altai Mountains Finally, on a high-mountain plateau at three sites at 1985-2150 m in the Altai Mountains near the junction of Russia, Kazakhstan, Mongolia, and China steppic vegetation prevailed through the entire late glacial, for the relatively temperate Bølling-Allerød phase is weakly represented in the pollen sequence (Blyakharchuk et al. submitted). It continued until about 8 ka 14C yr BP in the early Holocene before the full development of conifer forest. CONCLUSIONS In contrast to the well recorded late-glacial and early-Holocene vegetational history of temperate Western Europe, a review of pollen investigations from drier areas to the east the Pirin Mountains in Bulgaria, the western Black Sea area, the Near East, Georgia, and southwestern Siberia - suggests that the ubiquitous late-glacial cold dry Artemisia-chenopod semi-desert continued in the early Holocene until at least 8000 yr 14C BP with minor modifications. This conclusion is consistent with paleoclimate models that indicate dry

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early-Holocene conditions in continental interiors as a result of increased summer insolation related to Earth/Sun orbital changes. ACKNOWLEDGMENTS We dedicate this paper to Prof. Elissaveta Bozilova who inspired us to think about vegetation history in southeastern Europe and who helped in many ways during fieldwork and with thoughtful discussions of ideas and results. We are thankful to Walter Finsinger who helped with the figures. Field work in much of the area was supported by the National Geographic Society and the U.S. National Science Foundation. REFERENCES Ahlberg K, Almgren E, Wright HE Jr, Ito E, Hobbie S (1996) Oxygen-isotope record of late-glacial climatic change in western Ireland. Boreas 25: 257-267. Atanassova J (1995) Palynological data of three deepwater cores from the western part of the Black Sea. In: Bozilova E, Tonkov S (eds) Advances in Holocene palaeoecology in Bulgaria. Pensoft Publ, Sofia, pp 68-83. Atanassova J, Stefanova I (2003) Late Glacial vegetational history of Lake Kremensko-5 in the northern Pirin Mountains, southwestern Bulgaria. Veget Hist Archaeobot, in press. Blyakharchuk TA, Wright HE Jr, Borodavko PS, van der Knaap WO, Ammann B (submitted) Lateglacial and Holocene vegetational changes on the Ulagan high-mountain plateau, Altai Mountains, southern Siberia. Palaeogeogr Palaeoclimat Palaeoecol. Chepalyga AL (1984) Inland sea basins. In: Velichko AA, Wright HE Jr, Barnosky C (eds) Late Quaternary environments of the Soviet Union. Univ Minnesota Press, Minneapolis, pp 229-250. Digerfeldt G (1972) The Post-glacial development of Lake Trummen. Regional vegetation history, water-level changes and palaeolimnology. Folia Limnol Scand No 16: 104. von Grafenstein U, Eicher U, Erlenkeuser H, Ruch P , Schwander J, Ammann B (2000) Isotope signature of the Younger Dryas and two minor oscillations at Gerzensee (Switzerland): palaeoclimatic and palaeolimologic interpretation based on bulk and biogenic carbonates. Palaeogeogr Palaeoclimat Palaeoecol 159: 215-230. von Grafenstein U, Erlenkeuser H, Brauer A, Jouzel J, Johnson JS (1999) A mid-European decadal isotope climate record from 15,500 to 5000 years BP. Science 284: 1654-1657. Harrison SP, Digerfeldt G (1993) European lakes as palaeohydrological and paleoclimatic indicators. Quat Sci Rev 12: 233-248. IAEA/WMO (1998) Global network for isotopes in precipitation. The GNIP database. International Atomic Energy Agency, Vienna. Lemcke G (1996) Paläoklimarekonstruktion am Van See (Ostanatolien, Türkei). Diss ETH Zürich, No. 11786. Margalitadze N (1995) History of the Holocene Vegetation in Georgia. Academy of Sciences in Georgia, Botanical Institute, Series: Vegetation of Georgia. Metsniyereba, Tbilisi 191 (in Russian).

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Magny M, Miramont C, Sivan O (2002) Assessment of the impact of climate and anthropogenic factors on Holocene Mediterranean vegetation in Europe on the basis of hydrological records. Palaeogeogr Palaeoclimat Palaeoecol 186: 47-60. Rohling EJ, Hilgen FJ (1991) The eastern Mediterranean climate at times of sapropel formation: a review. Geologie en Mijnbouw 76: 253-264. Ryan WFG et al (1997) An abrupt drowning of the Black Sea shelf. Marine Geology 138: 119-126. Ryan WFG, Pitman WC III (1998) Noah’s Flood. Simon and Shuster, New York. Schwander J, Eicher U, Ammann B (2000) Oxygen isotopes of lake marl at Gerzensee and Leysin (Switzerland), covering the Younger Dryas and two minor oscillations, and their correlation to the GRIP ice core. Palaeogeogr Palaeoclimat Palaeoecol 159: 203-214. Stefanova I, Ammann B (2003) Late-glacial and Holocene vegetation belts in the Pirin Mountains (southwestern Bulgaria). Holocene 13, 1: 97-107. Stevens LR, Wright HE Jr, Ito E (2001) Proposed changes in seasonality of climate during the Lateglacial and Holocene at Lake Zeribar, Iran. Holocene 11: 747-755. van Zeist W, Bottema S (1991) Late Quaternary Vegetation of the Near East. Beihefte zum Tübinger Atlas des Vorderen Orients, Wiesbaden 18: 156. Wick L (2000) Vegetational response to climatic changes recorded in Swiss Late Glacial lake sediments. Palaeogeogr Palaeoclimat Palaeoecol 159: 231-250. Wick L, Lemcke G, Sturm M (2003) Evidence of late-glacial and Holocene climatic change and human impact in eastern Anatolia: high-resolution pollen, charcoal, isotopic, and geochemical data from the laminated sediments of Lake Van, eastern Turkey. Holocene, in press.

© PENSOFT Publishers Holocene vegetation Sofia - Moscow

Spassimir Tonkov (ed.) 2003 and human impact in the Apuseni Mountains, Central Romania 137 Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 137-170

Holocene vegetation and human impact in the Apuseni Mountains, Central Romania Guy Jalut1*, Antoniu Bodnariuc1,2, Anne Bouchette1, Jean-Jacques Dedoubat1, Thierry Otto1 and Michel Fontugne3 Laboratoire Dynamique de la Biodiversité (LADYBIO), Université Paul Sabatier, 39 Allées Jules Guesde, 31062 Toulouse Cedex 4, France. *E-mail: [email protected] 2 Faculty of Geology, Babes - Bolyai University, 1 Kogalniceanu str., 3400 Cluj Napoca, Romania 3 Laboratoire des Sciences du Climat et de l’Environment, Laboratoire mixte CNRS - CEA, Avenue de la Terrasse, 91198 Gif sur Yvette, France

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ABSTRACT From recent palynological investigations in the Apuseni Mountains (Transylvania, Romania) a chronology of the Holocene development of the forests was proposed. These studies demonstrated that evidence of human impact appeared during the 7800 – 7425 cal. BP period and for the first cultivations at ca. 6820 cal. BP. Between 4500 and 2750 cal. BP deforestation and agriculture were of limited importance Then they increased particularly around 1935 and 695 – 660 cal. BP. KEY WORDS: Romania – Apuseni Mountains – Pollen analysis – Holocene vegetation – Human impact

INTRODUCTION In Eastern Europe, in the region of contact between the subcontinental, mediterranean and steppic regions, Romania represents a particularly interesting field of investigation for the Lateglacial and Holocene studies on vegetation and climate. Geomorphomogical studies show that despite their altitude (maximum 2500 m), the Carpathians and the Apuseni Mountains (Fig. 1) were not strongly affected by glaciers during the last glacial episode (Ficheux 1996). Only traces of nivation niches oriented to the east, in the lee of dominant winds from the west, exist on the crests of Biharia or Vladeasa (Ficheux 1996). In the Apuseni Mountains, during the last cold and dry periods, the complexity of the relief partly linked to the extension of the karstic zones, probably favoured the persistence of sheltered areas favourable for the trees that form the present forests.

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This country was also occupied early by humans (communities of Carcea-Gura BaciuliOcna Sibiului type), moving into the Transylvanian highlands, from the beginning of the Neolithic (ca. 8000 cal. BP) onwards (Lazarovici 1993; Mantu 1998). Numerous palynological studies have been carried out in Romania starting with those of Pop (1929, 1934, 1942, 1962) then Ciobanu (1948, 1958, 1965). They were based on fundamental studies of plant distribution (Donita et al. 1960; Donita 1964, 1965; Georgescu and Donita 1965), peat bogs and humid zones (Pop 1960). These studies were compared

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with numerous other works in Eastern and Western Europe and a general schema for the Lateglacial and Holocene forest and climate history was proposed (Pop 1929, 1932, 1934, 1942). Unfortunately, until the recent works of Farcas et al. (1999) and Rösch and Fischer (2000), no 14C dates were available and in most cases the sampling intervals were too large to allow the solution of chronological problems. Except for the study of Rösch and Fisher (2000) no references to human impact were available. Recent palynological studies (Bodnariuc 2000; Bodnariuc et al. 2002) have established a chronology of the forest history in the Romanian Western Carpathians and new data on the human impact have been obtained. THE STUDY AREA Geology, geography and climate To the north, the east and the south, the Carpathian Mountains (Fig. 1) form a natural limit to the Hungarian plain from which emerge, in its eastern part, the Apuseni Mountains (Romanian Western Carpathians). Formerly called Bihor (Ozenda 1994) the Apuseni Mountains (1848 m) form a massif about 100 km in diameter. It occupies a central position in Transylvania (Ficheux 1996). Flat surfaces are rare in the Apuseni Mountains and the rivers are deeply cut in. Four morphological units can be distinguished: a) the high Bihor above 1000 m which has a complex geological structure including the karst region of Padis; b) the Metaliferi Mountains; c) the massifs and gulfs of the western slopes; d) the depression of Huedin and the Hungarian plain to the west. A cold continental climate characterizes this area. Rainfall is abundant from spring to autumn with a marked maximum in summer. The mean annual precipitation is about 1400 mm and the mean annual temperature is about 4.1°C. The winters are cold with an absolute minimal temperature equal or lower than -30°C. The summers are cool. Due to the complexity of the relief important local climatic differences exist in the Apuseni Mountains. To the west the annual precipitation is about 300 mm higher than to the east. The maximum of precipitation is concentrated in the central-western part of the mountains where the sites studied are located. The present climatic conditions favour the distribution of mountain forests in which Sphagnum peat bogs develop. Present vegetation The forests in the Apuseni Mountains are essentially composed of Fagus sylvatica and Picea abies. Spruce is concentrated in the central part of the massif while beech is mainly found around it. However, due to lumbering in the spruce forests, large areas are now colonised by beech which temporarily replaces spruce. Abies alba is rare. The strong human impact on the mountain forests has determined the extension of meadows where Festuca rubra, Nardus stricta, Calluna vulgaris and Calamagrostis arundinacea are found (Donita et al. 1960). At low altitudes, in depressions and corridors are growing oak-hornbeam forest

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composed of Quercus petraea, Quercus robur, Carpinus betulus, Fagus sylvatica, Tilia cordata, Acer pseudoplatanus, Acer platanoides, Corylus avellana, and Fraxinus excelsior. The abundance of Quercus, Fagus and Carpinus depends on the local ecological and historical factors. Distant from the massif, thermophilous oak forests with Quercus petraea, Quercus cerris, Quercus pubescens, Quercus fraineto, Fraxinus ornus and Prunus mahaleb occur on limestone areas. MATERIALS AND METHODS Sites of investigation Five cores were obtained from the northwestern part of the Apuseni Mountains using a Russian sampler (Fig. 2) (Bodnariuc 2000; Bodnariuc et al. 2002). The altitude of the sites ranges between 1000 and 1300 m asl. All sites are now ombrogenic Sphagnum peat bogs. The site of Ic Ponor (1020 m asl) (Fig. 2) lies on schists, at the foot of a slope. After a relatively short lacustrine phase during the early Holocene peat has begun to accumulate. The site covers 7 hectares on the right side of the Somesul Cald river near its confluence with the Batrana river. To the south an inundated zone is colonised by Carex rostrata. The peat bog is surrounded by spruce. Scattered stands of birch (Betula pubescens and Betula pendula) are present

Fig. 2. Location of the local cited and studied sites: 1 Mlastina lui Neag, 2 Izbucu I, 3 Izbucu II, 4 La Lacuri, 5 Pietrele Onachii, 6 La Mlastina, 7 La Mol, 8 Molhasu de la Calatele, 9 Dealu Negru, 10 Dambu Negru, 11 Ciurtuci, 12 Baita , 13 Ic Ponor I and II, 14 Bergerie, 15 Cimetière, 16 Padis.

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in deforested areas. Picea and Betula are also abundant in the peat bog. On its surface Vaccinium myrtillus and Vaccinium vitis-ideae form dense communities with abundant Eriophorum vaginatum. Sphagnum mosses cover the whole surface of the peat bog but Polytrichum is also present as well as Empetrum nigrum (Pop 1960). Because of the large size of the peat bog two cores were taken: Ic Ponor I (295 cm length) (Fig. 3) at the top of the peat bog, in the deepest zone, and Ic Ponor II (165 cm length) (Fig. 4) in the northwestern margin. The three other sites are situated to the west in the karst zone of Padis. Padis (1240 m asl) (Fig. 2) is a Sphagnum peat bog in one of the numerous sink holes present on the karst plateau. Some of these sink holes are small ponds colonised by hydrophilous communities. Others such as that of Padis have been transformed into Sphagnum peat bogs colonised by stands of spruce. The dominant shrubs are Vaccinium myrtillus and Vaccinium vitis-idaea. Dechampsia flexuosa, Carex echinata and Carex rostrata are also well represented. Sphagnum and Polytricum are the dominant mosses. Flat areas with meadows surround the site. Picea forest occupies the hills. On open deforested areas stands of Fagus sylvatica frequently occupy the hill tops. The core was collected at the centre of the peat bog. The bottom of the sequence is clay, poor in organic matter (Fig. 5). The peat bog of Cimetière (1280 m asl) (Fig. 2) is situated on a slope. It has a northwestern exposure and is located near a ridge in a zone strongly affected by forestry. It is surrounded by an old spruce forest partly destroyed by a storm. The peat bog belongs to a large complex where Sphagnum is dominant in most places. Other species such as Eriophorum vaginatum, Deschampsia flexuosa and Vaccinum myrtillus are abundant or frequent while Vaccinium vitisidaea, Homogyne alpina and Carex echinata are rare. The base of the core is formed of coarse gravel with a low pollen content and contains corroded grains of uncertain origin (Fig. 6). For these reasons only the Sphagnum peaty deposit was taken into account for the interpretation of the pollen data. Bergerie (1400 m asl) (Fig. 2) is a Sphagnum peat bog. Locally, Sphagnum sp. dominates in association with Carex rostrata, Eriophorum vaginatum, Carex echinata, Juncus effusus and Juncus conglomeratus. The bore was performed under 25 cm of water. The bottom of the sequence is argilous and poor in organic matter (Fig. 7). The site is situated above but near to the present upper limit of the spruce forest. The surrounding area is used as pasture land. Juniper (Juniperus communis) and young Picea abies trees colonise the meadows. Lithology Cores Ic Ponor I and II (Figs. 3 and 4) Despite their different depths the two cores show similar sedimentary facies (Bodnariuc 2000; Bodnariuc et al. 2002). The bottom is composed of a sandy-clay material with thin intercalated peat layers. This lacustrine phase corresponds to the period 10190–9660 cal. BP (levels 298-280, Ic Ponor I; 170-140, Ic Ponor 2). This sediment is overlain by a charcoal layer with some bark fragments, leaves and seeds. The abrupt transition corresponds to synchronous changes in pollen percentages: decrease in Betula, increase in Corylus, particularly

Fig. 3. Pollen diagram from Ic Ponor 1.

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Fig. 4. Pollen diagram from Ic Ponor 2.

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at Ic Ponor I (Fig. 3). The age of this transition is estimated at ca. 9650–9550 cal. BP taking into account the radiocarbon datings and the linear interpolation accepted. Up to levels 280-36 at Ic Ponor I and 145-38 at Ic Ponor II (ca. 4500 cal. BP) Sphagnum peat is observed. At level 44 (Ic Ponor I) charcoal fragments are present. In both sequences between levels 36-27 (Ic Ponor I) and 38-20 (Ic Ponor II) the mineral deposits with sand and clay indicate a flooded phase. At levels 22 (Ic Ponor II) and 15 (Ic Ponor II) a poorly decomposed Sphagnum peat contains charcoal. This charcoal layer is covered by recent Sphagnum peat. The comparison of the cores as well as the palynological data show that the deposits between levels 36-27 (Ic Ponor I) and 38-20 (Ic Ponor II) are contemporaneous. However, the radiocarbon datings of levels 34 (5680±110 BP, Ic Ponor I) and 35 (6460±110 BP, Ic Ponor II) are different (Table 1). In both cores the appearance of these lacustrine deposits corresponds to a synchronous increase in Fagus and Abies pollen percentages. At Bergerie (Fig. 7) and Padis (Fig. 5) such increases are not synchronous and are dated at 4050±80 BP (4500 cal. BP) and 3750±100 BP (4100 cal. BP), respectively (Table 1). Outside the study area in the Southwestern Carpathians (Banat Mountains) the two events seem synchronous and are dated at 3880±60 BP (Rösch and Fischer 2000). In all cases, these events occurred around 4500–4370 cal. BP. Consequently, it can be assumed that the ages of levels 34 and 35 of Ic Ponor I and II are too old. This age and the sedimentary facies Table 1. Radicarbon datings used in pollen diagrams (Ic I: Ic Ponor 1; Ic II: Ic Ponor 2; PAD: Padis; C: Cimetière; BER: Bergerie). Depth (cm) Bergerie

95-100 145-150 157-160 165-170 190-200 215-230 Padis 10-15 30-35 75-80 85-95 Ic Ponor 1 34 70 190 292-295 Ic Ponor 2 35 55 160 Cimetière 90-100

Material dated Sphagnum Sphagnum Plant macrorests Sphagnum Plant macrorests Plant macrorests Sphagnum Sphagnum Sphagnum Sphagnum Plant macrorests Plant macrorests Plant macrorests Plant macrorests Plant macrorests Plant macrorests Plant macrorests Plant macrorests

C yrs. BP

14

725 ± 85 3720 ± 60 4050 ± 80 5665 ± 120 6680 ± 80 7010 ± 182 modern 445 ± 80 3750 ± 100 4595 ± 65 5680 ± 110 6190 ± 90 6870 ± 90 8990 ± 80 6460 ± 110 6980 ± 90 8770 ± 90 7810 ± 110

Lab. ¹

Gif-11130 Gif-11131 GifA-99221 Gif-11133 GifA-99475 GifA-99476 Gif-11127 Gif-11128 Gif-11135 Gif-11129 GifA-100143 GifA-100146 GifA-100148 GifA-99669 GifA-100144 GifA-100145 GifA-100147 GifA-99220

Calibrated age (95,4 - 2 sigma)

δ13 C ‰

cal. BP cal. BC - AD 793 - 538 1157 - 1412 AD -25,9 4240 - 3891 2291 - 1942 BC -26,19 4825 - 4379 2876 - 2430 BC 6691 - 6272 4742 - 4323 BC -26,88 7664 - 7430 5715 - 5481 BC 8177 - 7562 6228 - 5613 BC -26,27 560 - 308 1390 - 1642 AD -25,8 4411 - 3864 2462 - 1915 BC -26,98 5470 - 5046 3521 - 3097 BC -26,8 6686 - 6281 4737 - 4332 BC 7270 - 6854 5231 - 4905 BC 7865 - 7570 5916 - 5621 BC 10268 - 9888 8319 -7939 BC 7571 - 7177 5622 - 5228 BC 7964 - 7659 6015 - 5710 BC 9969 - 9550 8020 - 7601 BC 8814 - 8406 6865 - 6457 BC

Fig. 5. Pollen diagram from Padis.

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Fig. 6. Pollen diagram from Cimetière.

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suggest that the dated plant remains preserved in the sediments were reworked and around levels 35-30 there might be a hiatus of about 2000 years. At Ic Ponor II the estimated age of level 40 obtained by linear interpolation (6000 BP: 6820 cal. BP) reinforces this hypothesis as does palynological data. The age of layer 35-12 can be estimated by a comparison with the pollen data from Bergerie and Padis. In these sites between 4200 cal. BP and 680 cal. BP the percentages of Carpinus are frequently above 10%. At Ic Ponor-I above level 35 they do not exceed 5-6%. For this reason it can be assumed that in both cores the deposits between 35 and 12 cm are younger than 680 cal. BP. Above it the pollen content of Sphagnum corresponds to the recent periods. Core Padis (Fig. 5) Clay deposits with gravel and sand are observed between levels 95 and 80. They are covered up to level 27 by Sphagnum peat. It is poorly decomposed between levels 27 and 9. Core Cimetière (Fig. 6) White clay with gravel, poor in organic matter, forms the bottom part of the sequence. Plant macroremains are observed at levels 125 and 118. Between levels 90 and 53 the content of the organic matter slowly increases and some undeterminable plant macroremains occur. A sandy sediment is observed between levels 53 and 42.5 and the organic content slowly increases. Above it a thin grey sandy layer is present between levels 42.5 and 40 overlain by Sphagnum peat up to level 15. This diversity of facies suggests frequent changes in the sedimentation and erosion processses. The strong variations in the percentages of Pinus and Corylus between levels 130 and 80 are not observed in the other cores and support this hypothesis. Core Bergerie (Fig. 7) A lacustrine deposit between levels 230 and 90 presents three facies: 230-190 - sandy clay with some gravel; 190-145 - clay with some gravel; 145-90 - clay with plant remains. Peat appears at level 90. This abrupt sedimentary transition does not correspond to strong variations in pollen percentages which might indicate a possible gap of sediment. If such an event did occur, it was short and without any major consequences on the pollen representation. Between levels 90 and 25 decomposed peat is regularly found. Sphagnum is observed between levels 20 and 12. Pollen analysis Samples of one cubic centimeter were taken to extract pollen grains and spores using a calibrated sampler. Classical procedures were used to eliminate organic matter and mineral fraction. For the calculation of the pollen concentration the slides were prepared according to Cour (1974). The pollen concentrations are expressed as number of pollen grains per cm3. For each level about 300-400 grains were counted which represents a statistically significant sample. After counting each slide was checked for rare pollen grains. Thousands of pollen grains and spores were thus observed per slide.

Fig. 7. Pollen diagram from Bergerie.

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The pollen sum for percentage calculations includes pollen types of trees, shrubs and herbs. Local pollen grains of hydrophilous and hygrophilous taxa, including Cyperaceae, as well as spores of mosses and ferns were excluded from the pollen sum (Janssen 1973) Their participation was calculated as a proportion of the pollen sum. In the pollen diagrams only the most significant taxa are indicated. Each pollen diagram was divided into Local Pollen Assemblage Zones (LPAZ) as defined by Cushing (1963), Berglund and Ralska-Jasiewiczowa (1986). Regional Pollen Assemblage Zones (RPAZ) were defined after comparisons between the pollen diagrams. Radiocarbon dating In many cases the samples for dating were extracted from Sphagnum peat which excluded the possibility of ageing by hard water effect. At Padis, Cimetière and Bergerie the low level of organic matter at the base of the cores required ≤15 cm of sediment per dating. The peat samples at Padis and Bergerie ranged between 3-5 cm. All the dates at Ic Ponor were obtained by AMS using unidentified terrestrial plant macroremains from thin layers (Table 1). Additional estimated ages were obtained by comparing the neighbouring sites and from linear interpolations. The radiocarbon dates were calibrated using the radiocarbon calibration program REV 4.3 (Stuiver et al. 1998). In the text the dates are given in cal. yrs. BP. Their consistency is discussed in the following chapters. RESULTS Local and regional pollen stratigraphy The pollen diagrams were divided into LPAZ: Ic Ponor I, 13 LPAZ (Fig. 3, Table 2); Ic Ponor II, 13 LPAZ (Fig. 4, Table 3); Padis, 12 LPAZ (Fig.5, Table 4); Cimetière, 13 LPAZ (Fig. 6, Table 5) and Bergerie, 13 LPAZ (Fig. 7, Table 6) (Bodnariuc et al. 2002). Nine Regional Pollen Assemblage Zones (RPAZ) were identified using the information from the LPAZ, the sedimentary data, the radiocarbon datings and the estimated ages obtained by interpolation (Table 7) (Bodnariuc et al. 2002): RPAZ 1: Betula - Picea - Ulmus - Corylus - Pinus (10190 – 9660 cal. BP), represented only in Ic Ponor I and II. RPAZ 2: Corylus - Picea - Ulmus - Fraxinus - Alnus (9660 – 7700 cal. BP), represented only in Ic Ponor I and II. RPAZ 3: Picea - Corylus - Ulmus (7700 – 7250 cal. BP), common to Ic Ponor I and II and Bergerie. Fagus pollen is rare but regularly present. RPAZ 4: Picea - Corylus - Ulmus - Alnus (7250 – 6600 cal. BP), common to Ic Ponor I and II and Bergerie. Pollen of Fagus, Carpinus and Abies is rare but present.

Picea-Poaceae-Betula-Cerealia

Picea-Poaceae-Cerealia

Ic 1-13 0-5

Ic 1-12 5-15

Picea-Corylus

Corylus-Picea

Picea-Corylus-Ulmus

Picea-Corylus-Fraxinus

Ic1-8 35-45

Ic 1-7 45-55

Ic1-6 55-70

Ic 1-5 70-95

Ic 1-4 95-190 Picea-Corylus-Ericaceae

Picea-Corylus-Fagus

Ic 1-9 25-35

Ic 1-10 20-25 Picea-Corylus-Fagus-Poaceae

Ic 1- 11 15-20 Picea-Fagus-Corylus-Poaceae-Cerealia

LPAZ name

LPAZ/ Depth (cm) Decrease in Poaceae and Picea, slight increase in Pinus and Fabaceae, presence of Centaurea cyanus. Decrease in Picea and Fagus, increase in Fabaceae.Upper limit : decrease in Poaceae and Picea. Decrease in Corylus and Alnus, increase in Picea, Fagus, Poaceae, small increase in Carpinus. First presence of Cerealia.Upper limit: decrease in Fagus, Picea and Carpinus Decrease in Picea, slight decrease in Abies, increase in Poaceae, maximum of Ericaceae.Upper limit : increase in Poaceae, Fagus and Picea, decrease in Ericaceae. Strong decrease in Picea, increase in Fagus, Carpinus and Alnus. Increase in Poaceae and Ericaceae, occurrences of Plantago lanceolata, decrease in Ulmus.Upper limit : decrease in Picea and Abies, slight increase in Chenopodiaceae. Increase in Picea, decrease in Corylus and Quercus. Small increase in Fagus and Abies.Upper limit : decrease in Picea, increase in Carpinus and Fagus. Increase in Corylus and Quercus, strong decrease in Picea.Upper limit : increase in Picea, decrease in Corylus and Quercus. Increase in Picea, decrease in Fraxinus. Regular presence of Carpinus and Abies with low values. Fagus regularly present but rare. Small increase in Artemisia and Humulus-Cannabis type.Upper limit : decrease in Picea, increase in Corylus. Decrease in Corylus. Small increase in Fagus and decrease in Ericaceae.Upper limit : regular presence of Carpinus and Abies, increase in Picea. Dominance of Picea and Corylus. Regular presence of Fagus with low values. Occurrences of Abies and Carpinus. Occurrences of Chenopodiaceae, Urticaceae and Rumex. Increase in Humulus-Cannabis type at the end of the phase.Upper limit : increase in Fagus, decrease in Corylus and Ericaceae.

Main features of the LPAZ

Table 2. Description of the local pollen assemblage zones in the Ic Ponor 1 profile.

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Dominance of Corylus and Picea, increase in Ericaceae and Humulus-Cannabis type. Decrease in AP/T values.Upper limit : decrease in Corylus, regular presence of Fagus. Abrupt fall in Betula values, increase in Corylus and Picea, occurrences of Rumex, sporadic presence of Fagus and Carpinus.Upper limit : fall in Corylus, increase in Ericaceae and Humulus-Cannabis type. Abundance of Betula, Picea between 10 and 18%, decrease in Pinus.Upper limit : fall in Betula values, increase in Corylus and Betula.

Fabaceae-Rosaceae-Picea-Corylus-Cerealia

Ic 2-13 5-15

Picea-Corylus-Ulmus-Quercus

Picea-Corylus

Ic 2-9 35-40

Ic 2-8 40-55

Ic 2-10 30-35 Picea-Corylus-Fagus

Ic 2-11 20-30 Picea-Corylus-Fagus-Alnus

Ic 2-12 15-20 Picea-Corylus-Fagus-Carpinus

LPAZ name

LPAZ/ Depth (cm)

Strong decrease in Picea and Corylus. Slight decrease in Carpinus, Fagus and Poaceae. Abundance of Fabaceae. Urticaceae and Centaurea cyanus well represented. Presence of Cerealia. Strong decrease in Corylus, increase in Picea and Carpinus, Poaceae and Ericaceae.Upper limit: decrease in AP/T ratio, Picea, Betula and Corylus. Increase in Alnus, slight increase in Cannabis-Humulus type, occurrences of Urticaceae.Upper limit : decrease in Corylus, increase in Carpinus and Picea. Increase in Fagus, Alnus, Betula and Picea, decrease in Corylus, Ulmus and Fraxinus. Beginning of the regular presence of Carpinus and occurrences of Abies. Increase in Plantago lanceolata, Chenopodiaceae and Poaceae.Upper limit : increase in Alnus and Picea, decrease in Fagus. Decrease in Picea, increase in Corylus, Quercus, Ulmus and Betula.Upper limit : decrease in Corylus, Ulmus and Quercus, increase in Fagus. Picea dominant, regular presence of Fagus with low values. Slight increase in Poaceae then Ericaceae, first occurrences of Abies.Upper limit : decrease in Picea, increase in Corylus.

Main features of the LPAZ

Table 3. Description of the local pollen assemblage zones in the Ic Ponor 2 profile.

Ic 1-1 280-295 Betula-Picea-Ulmus-Corylus-Pinus

Ic 1-2 220-280 Corylus-Picea-Ulmus-Fraxinus

Ic 1-3 190-220 Corylus-Picea-Ulmus-Fraxinus-Ericaceae

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Picea-Corylus-Ulmus-Fraxinus

Increase in Picea, synchronous decrease in Corylus. Slight increase in Poaceae then Artemisia. Occurrences of Fagus.Upper limit : beginning of the Fagus curve, decrease in Ulmus. Peaks of Picea in the first part of the zone, Corylus stable, AP/T values at their maximum.Upper limit : increase in Picea, decrease in Corylus and Ulmus. Dominance of Corylus, Picea stable around 20%, decrease in Poaceae. Peak of Pinus at the end of the phase. First occurrences of Carpinus and Fagus.Upper limit: increase in Picea, small decrease in Betula. Increase in Corylus, Fraxinus and Picea, decrease in Betula.Upper limit : decrease in Poaceae and Fraxinus. Increase in Corylus, decrease in Picea and Betula. Small increase in Alnus.Upper limit : decrease in Betula, increase in Picea and Corylus. Decrease in Betula, slight increase in Corylus, increase in Picea, small increase in Poaceae.Upper limit : decrease in Betula and Picea, increase in Corylus. Increase in Betula, decrease in Picea and Pinus. Upper limit : decrease in Betula, increase in Picea.

Poaceae-Fagus-Picea-Carpinus-Corylus-Quercus

Pad. 12 5-11

Pad. 10 15-20 Poaceae-Fagus-Picea-Cerealia

Pad. 11 11-15 Poaceae-Fagus-Picea-Carpinus-Cerealia

LPAZ name

LPAZ/ Depth (cm)

Small decrease in Poaceae, Picea and Carpinus, slight increase in Fagus, Quercus, Corylus and Pinus. Decrease in Poaceae and synchronous increase in Fagus, Picea, Carpinus, Quercus and Pinus.Upper limit : decrease in Poaceae, increase in Fagus. Abrupt increase in Poaceae and synchronous decrease in Fagus and Picea. Cerealia, Plantago, Rumex and Chenopodiaceae well represented,Upper limit : decrease in Poaceae, increase in Fagus and Picea.

Main features of the LPAZ

Table 4. Description of the local pollen assemblage zones in the Padis profile.

Ic 2-1 160-165 Betula-Picea-Ulmus-Corylus-Pinus

Ic 2-2 150-160 Betula-Picea-Corylus

Ic 2-3 145-150 Corylus-Betula-Picea-Ulmus

Ic 2-4 135-145 Corylus-Picea-Ulmus-Betula

Ic 2-5 115-135 Corylus-Picea-Ulmus-Fraxinus

Ic 2-6 75-115 Corylus-Picea-Ulmus-Fraxinus

Ic 2-7 55-75

Table 3. Continued.

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Fagus-Poaceae-Picea-Corylus-Quercus

Fagus-Poaceae-Picea

Fagus-Picea-Abies

Fagus-Picea-Carpinus-Poaceae-Abies

Fagus-Picea-Carpinus-Abies

Fagus-Picea-Abies-Carpinus

Corylus-Carpinus-Fagus-Picea-Abies

Corylus-Carpinus-Picea-Fagus

Corylus-Picea-Poaceae

Pad. 9 20-25

Pad. 8 25-30

Pad. 7 30-40

Pad. 6 40-50

Pad. 5 50-55

Pad. 4 55-70

Pad. 3 70-80

Pad. 2 80-85

Pad. 1 85-90

Increase in Picea, decrease in Quercus, slight increase in Fagus, decrease in Chenopodiaceae.Upper limit : increase in Poaceae, decrease in Fagus and Picea. Decrease in Picea and Abies, increase in Quercus and Betula, Poaceae, Chenopodiaceae, Rumex, Plantago and Cerealia.Upper limit : slight increase in Fagus and Picea, decrease in Chenopodiaceae. Fall in Carpinus, decline in Fagus, increase then decline in Picea and Abies. Increase in Chenopodiaceae at the end of the phase.Upper limit : decline in Picea and Abies, increase in Poaceae and Chenopodiaceae. Optimum of Fagus, small variations in Picea and Carpinus and increase in Poaceae and Corylus. Small increase in Artemisia.Upper limit : decrease in Fagus and Carpinus, increase in Picea and Abies. Increase in Picea , Carpinus and Chenopodiaceae. Small decrease in Abies and small increase in Fagus.Upper limit : decrease in Carpinus and Picea, increase in Poaceae. Small increase in Abies and Fagus, fluctuations of Carpinus and Corylus, small increase in Chenopodiaceae. Beginning of the AP/T decline at the end of the phase.Upper limit : Increase in Picea, Carpinus and Chenopodiaceae Decrease in Corylus, Carpinus Ulmus. Increase in Abies, Fagus and Picea. Small increase in Juglans.Upper limit : decrease in Carpinus, small increase in Corylus. Decrease in Corylus and increase in Carpinus and Fagus. Small increase in Quercus and Abies. Presence of Juglans.Upper limit : increase in Abies and Fagus, decrease in Corylus and Carpinus. Increase in Corylus ,decrease in Poaceae. Carpinus, Fagus and Abies present but rare.Upper limit : decrease in Corylus, increase in Carpinus and Fagus.

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RPAZ 5: Picea - Corylus - Carpinus (6600 – 4500 cal. BP), common to Cimetière, Bergerie and the base of Padis. Presence of Fagus and Abies. RPAZ 6: Picea - Carpinus - Fagus (4500 – 4100 cal. BP), not represented in Ic Ponor I and II but common to Padis, Cimetière and Bergerie. RPAZ 7: Fagus - Picea - Carpinus - Abies (4100 – 1940 cal. BP), common to Padis, Cimetière and Bergerie. RPAZ 8: Fagus - Picea - Carpinus - Abies - Poaceae (1940 – 480 cal. BP), common to Padis, Cimetière and Bergerie. RPAZ 9: Fagus - Picea - Carpinus - Abies - Cerealia (480 cal. BP – Present), common to Ic Ponor I and II, Padis, Cimetière and Bergerie. DISCUSSION Correlation of the pollen diagrams and local chronology The comparison of the five pollen diagrams shows that the Lateglacial and the beginning of the Postglacial period between 11000 BP and 10290 cal. BP are not represented in the sites studied. This does not allow us to describe the role of Pinus and Betula or to date the beginning of the Picea curve. The present data concern the last 10200 years. At Ic Ponor between ca. 10200 BP and 9700–9600 BP (RPAZ 1, Table 7) Betula played a major role. Afterwards during RPAZ 2 it regressed and was replaced by Corylus and Picea. This expansion of Betula might be the consequence of fires which occurred around 10200–9650 cal. BP as indicated by the presence of charcoal particles (Ic Ponor I: levels 290 to 285; Ic Ponor II: level 165). Charcoal of Picea was determined thus demonstrating the local presence of this tree at that time (M. Thinon, pers. com.). The surrounding Picea - Corylus forest was probably strongly modified and birch colonized the area. Then Corylus and Picea recovered. Pinus and Betula were poorly represented everywhere except in RPAZ 1 and 2. At a lower stage the oak forest was regularly represented with Ulmus values reaching 10%. But at the altitude of the site between 10200 and 6800 cal. BP (mid RPAZ 4, Table 2) Corylus and Picea were the regional dominant species. This period corresponds to the Picea - Corylus - Quercetum mixtum phase defined by Pop (1932). Good correlations exist between the two cores of Ic Ponor, particularly from 10200 to 6800 cal. BP, and a reference level is recorded ca. 7700 cal. BP (6870±90 BP Ic Ponor I; 6980±90 BP, Ic Ponor II) when the continuous Fagus curve begins. At that time correlation with the pollen diagram of Bergerie becomes possible. The bottom of this sequence dated at 7010±80 BP (7800 cal. BP) does not contain pollen grains of Fagus. For this reason it might belong to upper RPAZ 2. Fagus pollen appears above, before 76007500 cal. BP (6680±80 BP) and the first centimeters of the core belong to the transition between RPAZ 2 and 3. In RPAZ 3 most of the curves of Bergerie are similar to those of Ic Ponor I and II except that of Picea. This tree was well developed at Ic Ponor from 10200 cal. BP onwards but it started to spread at Bergerie only after 7800 cal. BP.

LPAZ name

Main features of the LPAZ

Poaceae-Fagus-Filicales-Picea-Carpinus-Corylus Strong decrease in Poaceae, Cyperaceae and Filicales. Slight increase in Fagus, Picea, Abies and Carpinus. Cim. 12 5-10 Poaceae-Fagus-Filicales-Picea Decrease in Picea, small increase in Fagus, increase in Poaceae and Filicales, presence of Vitis.Upper limit : Fall in Poaceae, Cyperaceae and Filicales. Cim. 11 10-15 Fagus-Pinus-Picea Decrease in Fagus and synchronous increase in Picea, presence of Olea.Upper limit : decrease in Picea, increase in Poaceae. Cim. 10 15-30 Fagus-Poaceae-Filicales-Corylus Scarcity of Carpinus, dominance of Fagus, regular presence of Juglans and Cerealia. Small increase in Poaceae, Chenopodiaceae, Urticaceae, Rumex, Plantago.Upper limit : fall in Fagus percentages, increase in Picea Cim. 9 30-50 Fagus-Poaceae-Filicales-Picea Increase in Fagus, decrease in Carpinus. Increase in Artemisia, regular presence of Chenopodiaceae, Rumex and Plantago lanceolata .Upper limit : decline in Picea, beginning of Juglans. Cim. 8 50-65 Corylus-Fagus-Filicales-Carpinus-Abies Beginning of the Abies curve. Strong increase in Fagus (2 to 20%) and synchronous decrease in Corylus(30 to 10%). Decline in Ulmus. Small increase in Chenopodiaceae and Artemisia, presence of Rumex.Upper limit : increase in Fagus, Artemisia and Rumex, decrease in Corylus. Increase in Fagus and beginning of the regular presence of Chenopodiaceae Cim. 7 65-70 Corylus-Filicales-Carpinus-Picea and Urticaceae. Decrease in Corylus.Upper limit : increase in Abies and Fagus, decrease in Corylus. Cim. 6 70-80 Corylus-Filicales-Picea-Carpinus Increase in Carpinus and Alnus , decrease in Ulmus and Poaceae. Small increase in Picea.Upper limit : increase in Fagus, decrease in Corylus Cim. 5 80-90 Pinus-Corylus-Filicales Strong decrease in Pinus (50 to 2%) and Filicales, increase in Corylus, Ulmus, Tilia and Poaceae, beginning of the curve of Cannabis-Humulus.Upper limit : increase in Carpinus, decrease in Poaceae. Cim. 4 90-95 Pinus-Filicales-Corylus-Picea Strong increase in Pinus and Filicales, decline in Corylus, Ulmus, Alnus, Picea and Poaceae.Upper limit : abrupt decrease in Pinus and Filicales, increase in Corylus and Poaceae.

Cim. 13 0-5

LPAZ / Depth (cm)

Table 5. Description of the local pollen assemblage zones in the Cimetière profile.

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Corylus-Filicales-Picea

Abrupt decrease in Pinus and increase in Corylus. Increase in Picea and Poaceae.Upper limit : increase in Pinus and Filicales, decrease in Corylus and Ulmus. Decrease in Filicales, Picea and Pinus, increase in Poaceae and Apiaceae. Increase in Ulmus and high values (15%) at the end of the phase.Upper limit : decrease in Pinus and Filicales, increase in Corylus and Picea. Abundance of Filicales (35-60%), Picea at 15%, decrease in Corylus, increase in Pinus.Upper limit : decrease in Pinus and Picea

Poaceae-Fagus-Picea-Abies-Carpinus

Poaceae-Fagus-Picea-Carpinus-Abies

Berg. 12 30-70

Berg. 11 70-90

Berg. 9 95-110

Fagus-Picea-Poaceae-Carpinus-Abies

Berg. 10 90-100 Fagus-Poaceae-Picea-Carpinus

Poaceae-Picea-Fagus

LPAZ name

Berg. 13 25-30

LPAZ/ Depth (cm)

Abrupt increase in Poaceae, increase in Chenopodiaceae, Cichorioideae, Rumex, Plantago lanceolata and Cerealia. Strong increase in Abies at the beginning of the phase. Increase in Poaceae, Plantago, Humulus-Cannabis type and Rumex. Regular decrease in Carpinus. Decrease then stabilization in AP/T. First occurrence of Cerealia at the end of the phase.Upper limit : fall in Fagus, Picea,Abies and Carpinus. Strong increase in Poaceae. Increase in Poaceae, Rumex and Artemisia. Slight decrease in Fagus and AP/T. Upper limit : increase in Abies, decrease in Fagus and Picea. Small increase in Car pinus, decrease in Picea and Fagus. Increase in Artemisia.Upper limit : increase in Poaceae, decrease in Carpinus. Increase in Poaceae then Artemisia at the end of the phase. Small increase in Abies, Betula and Chenopodiaceae, regular occurrence of Humulus-Cannabis type and Plantago lanceolata. Decrease in AP/T. Upper limit : decrease in Picea, Fagus and Poaceae.

Main features of the LPAZ

Table 6. Description of the local pollen assemblage zones in the Bergerie profile.

Cim. 1 115-130 Filicales-Corylus-Pinus-Picea-Poaceae

Cim. 2 105-115 Filicales-Pinus-Picea

Cim. 3 95-105

Table 5. Continued.

156 Guy Jalut et al.

Berg. 1 205-220 Corylus-Asteroideae-Poaceae-Picea-Ulmus

Berg. 2 195-205 Corylus-Asteroideae-Picea

Berg. 3 184-195 Corylus-Asteroideae-Picea-Ulmus

Berg. 4 170-184 Corylus-Picea-Asteroideae-Ulmus

Berg. 5 160-170 Corylus-Picea-Carpinus-Ulmus

Berg. 6 145-160 Corylus-Carpinus-Picea-Fagus

Berg. 7 120-145 Carpinus-Picea-Fagus-Corylus-Abies

Berg. 8 110-120 Fagus-Picea-Carpinus-Poaceae-Abies

Fall in Carpinus, increase in Poaceae, Rumex and Urticaceae. Beginning of the regular presence of Plantago lanceolata. Small increase in Pinus.Upper limit : increase in Poaceae and Humulus-Cannabis type, decrease in Picea. Regular increase in Fagus, small decline in Picea, decrease in Ulmus. Small but regular increase in Abies and Poaceae. Beginning of the regular occurrence of Chenopodiaceae and Cichorioideae. First occurrence of Plantago lanceolata.Upper limit : fall in Carpinus, increase in Ranunculaceae, Rumex and Urticaceae. Decrease in Corylus, increase in Fagus, Carpinus and Picea. Small decrease in Asteroideae, small increase in Poaceae. Regular presence of Abies at the end of the phase.Upper limit : increase in Abies, Fagus and Alnus, decrease in Corylus. Increase in Carpinus and Salix, decrease in Corylus except at the end of the phase. Small decrease in Poaceae and Asteroideae. Increase in Pinus at the end of the phase. Presence of Abies.Upper limit : increase in Fagus, Carpinus and Picea, decrease in Corylus and Pinus. Increase in Picea, small decrease in Asteroideae, Cichorioideae, Poaceae, Rumex, Humulus-Cannabis type. Decline in Corylus with abrupt changes. Increase in Poaceae, Fraxinus and Betula at the end of the phase. Presence of Abies.Upper limit : increase in Carpinus and Salix, decrease in Poaceae. Decrease in Corylus at the beginning of the phase,increase in Ulmus then Pinus at the end of the phase. Small increase in Cannabis-Humulus type. Picea stable.Upper limit : increase in Picea, abrupt fall in Corylus, beginning of the regular presence of Betula. Increase in Picea, decline in Corylus, small increase in Cichorioideae and Rumex then Artemisia. First presence of Abies.Upper limit : increase in Ulmus, decrease in Artemisia. High values of Corylus and Asteroideae. Values of Ulmus and Picea around 5%. Presence of Fagus and Carpinus.Upper limit : increase in Picea, Quercus and Cichorioideae.

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Because of the sedimentary characteristics of the cores at Ic Ponor around 6600–6500 cal. BP, comparisons between Bergerie and Ic Ponor I are limited to RPAZ 3 and 4. Taking into account the estimated dates obtained from interpolation at Ic Ponor 1 and Bergerie, the boundary between the two phases might be placed around 7250 cal. BP, when Picea values increased at Bergerie and those of Fagus at Ic Ponor I. At Bergerie the lower and upper boundaries of RPAZ 4 are defined by the increase of Picea and Carpinus at 7250 cal. BP and 6600–6400 cal. BP (5665±80 BP) respectively. The expansion of Carpinus is also a good reference event allowing a correlation to be established between the sequences of Cimetière and Bergerie. At Cimetière, before this event, in addition to the description of the core, several palynological observations suggest disturbances in the sedimentation processes: the abrupt change in the percentages of Pinus, Corylus and Poaceae at the clay-peat transition; the strong variations in the percentages of Pinus and Corylus between levels 130 and 90, and at the bottom of the sequence the record of high Carpinus and Fagus values that are not observed at Bergerie and Ic Ponor. Both the situation of the peat bog at the top of a western slope exposed to strong winds and rainfalls and the local human impact explain that run-off has affected the sedimentary processes. For these reasons the deposits from the bottom up to level 40 were considered as unsuitable for radiocarbon datings and those between levels 130 and 80 were rejected for a paleoecological reconstruction. The pollen diagram of Cimetière was subdivided using the data from Bergerie and Padis. During the early Holocene represented by RPAZ 1 to 4 sporadic occurrences of Carpinus, Fagus and Abies are observed. At Ic Ponor, the first Carpinus pollen was noted near 9500-8900 cal. BP, then regularly observed ca. 7800 cal. BP at Bergerie and ca. 7700–7600 cal. BP at Ic Ponor. At Ic Ponor and Bergerie Abies pollen occurred around 7600–7500 cal. BP. Fagus is found around 9400–9000 cal. BP at Ic Ponor and from 7800 cal. BP onwards at Bergerie. These occurrences suggest the existence of scattered stands situated at low and mid elevation during the early Holocene. It can be assumed that they probably originate from regional Glacial and Lateglacial refuges (Bodnariuc 2000; Bodnariuc et al. 2002). From RPAZ 5 to 9 (ca. 6450 cal. BP to present) the pollen diagrams of Bergerie, Padis and Cimetière can be compared. At Padis between 4650 and 4100 cal. BP, in the upper part of RPAZ 5, the percentages of Carpinus are low (2%) compared with Bergerie (near 5%) and Cimetière (near 10%). At Padis, Cimetière and Bergerie the increase in Fagus and Carpinus, and the synchronous decrease in Corylus characterize the beginning of RPAZ 6 dated ca. 4500 cal. BP (4050±80 BP) at Bergerie. This age, deduced from that of levels 160-155 from Bergerie (4050±80 BP), was preferred to that of the bottom of Padis (4595±65 BP, 5300 cal. BP) for three reasons: at Padis the thickness of the sample is 15 cm and at Bergerie only 5 cm; at Padis the dated sediment concerns material below the beginning of the Fagus curve; comparison between the dates obtained for the Fagus expansion at Bergerie (4050±80 BP) and in the Southwestern Carpathians, the Banat mountains (3880±60 BP; Rösch and Fischer 2000), shows an age close to 4500 cal. BP.

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Table 7. Time-space correlation of local and regional pollen assemblage zones: A=Abies, Al=Alnus, Ast=Asteroideae, Be=Betula, Ca=Carpinus, Ce=Cerealia, Co=Corylus, E=Ericaceae, Fab=Fabaceae, F=Fagus, Fr=Fraxinus, P=Pinus, Pi=Picea, Po=Poaceae, Q=Quercus, Ro=Rosaceae, U=Ulmus. L.P.A.Z. yrs cal BP 0

Ic 1

Ic 2

Padis

12 Pi-Po-Bet-Ce 11 Fab-Po-Pi-Co-Ce 12 11 11 Fi-Pi-Po-Ce 10 Pi-Co-F-Ca 10 10 Pi-F-Co-Ce 9 8

7

1000

R.P.A.Z.

Po-F-Pi-Ca-Co-Q Po-F-Pi-Ca Po-F-Pi-Ce F-Po-Pi-Co-Q-Ce F-Po-Pi

Cimetière 13 12 11

Po-F-Fi-Pi-Ca-Co Po-F-Fi-Pi F-P-Pi-Ce

F-Pi-Ab

6

F-Pi-CaPo-Ab

5

F-PiCa-Ab

4

F-PiAb-Ca

Bergerie 13 Po-Cy-Fi-Pi-F 12

Cy-Fi-Po-F

11 10

Fi-Po-F Fi-F-Po-Pi-Ca

F-PoFi-CoCe

9

9

F-PoFi-Pi

8

Fi-F-PiCa-Po-Ab

8

Co-F-Fii Ca-Ab

7

Fi-Ca-PiF-Co-Ab

7

Co-Fi-Pi-Ca

6

Fi-Co-Ca-Pi-F

6

Co-FiPi-Ca

5

Fi-CoPi-Ca

10

9

Pi-FAb-CaPo-Ce

8

F-Pi-Ca-Ab-Pa-Ce

7

F-PiCa-AbPo

6

Pi-CaF-Ab-

5

Pi-CoCa-FAb

4

Pi-CoU-Al-FCa-Ab

3

Pi-CoU-F

2

Co-PiU-FrAl

1

Be-PiU-Co-P

Fi-F-PiPo-Ca-Ab

2000 Hiatus

Hiatus

3000

3

Co-Ca-FPi-Ab

2

Co-Ca-Pi-F

4000

1

Co-Pi-Po

5000 9

Pi-Co-F

9

Pi-CoF-Al

8

Pi-Co-F

6000

8

7000

8000

Pi-Co

7

Co-Pi

6

Pi-Co

5

Pi-Co

4

Pi-Co-E 7

Pi-Co

3

Co-Pi-U- 6 Fr-E

Pi-Co-U

5 9000

2

Co-Pi-UCo-P 4 3 2

10000

Be-Pi-U1 Co-P

5 P-Co-Fi 4 4 P-Fi-Co-Pi 3 Co-Fi-Pi 3 2 2 F-P-Pi 1

Fi-CoPi-Ast Fi-Co-AstPi-U Fi-Co-Ast-Pi Fi-Co-Ast-Po-Pi-U

1 Fi-Co-PPi-Po

Co-PiU-Fr Co-PiBe-U-Fr Co-Pi-Be-U-Fr

Be-Pi-Co

1 Be-Pi-UCo-P

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The beginning of RPAZ 7 corresponds to the spread of Abies dated ca. 4200 cal. BP (3720±60 BP) at Bergerie. The end of RPAZ 7 is not dated. The proposed boundary at 1940 cal. BP is based on an interpolation between the radiocarbon datings of Bergerie (3720±60 BP and 725±85 BP) and Padis (3750±100 BP and 445±80 BP). At Bergerie, Cimetière and Padis this boundary corresponds to a decrease in the AP/T ratio and Corylus values. At Bergerie it is also marked by a decrease in the percentages of Carpinus. At that time the human impact described below was the determining factor of the landscape history. The boundaries of RPAZ 8 and 9 correspond to major changes observed at the three sites. However, because of the difference in the local human impact complete analogies are difficult to be found. RPAZ 8 begins with a decrease in AP/T ratio and an increase in the anthropogenic indicators. It ends when Poaceae values increase. According to the sites, Juglans is regularly present (Cimetière and Padis) and the percentages of Carpinus, Fagus and Picea decrease. At Padis the upper boundary of RPAZ 8 is dated ca. 500 cal. BP (445±80 BP). RPAZ 9 corresponds to a phase of intensive human activity well characterized by the anthropogenic indicators. The AP/T value falls and strong deforestations are recorded. According to Bodnariuc et al. (2002) the main features of the vegetation history of the Apuseni Mountains can be summarized as follows. In the Apuseni Mountains Pinus and Betula were never important forest components between 10190 cal. BP till present. At Ic Ponor the peak of Betula close to 9850 cal. BP corresponds to a local development associated to natural forest fires. The beginning of the expansion of Picea occurred prior to 10190 cal. BP and around 11180 cal. BP (Farcas et al. 1999). Between 10190 and 6450 cal. BP Corylus and Picea were dominant at mid-altitudes (the Picea - Corylus - Quercetum mixtum phase). Carpinus occurred at low and medium elevation ca. 6450 cal. BP. The Picea-Carpinus phase ended around 4500 cal. BP when Fagus started to spread. The development of Abies occurred slightly later ca 4100 cal. BP. Then the Picea Carpinus - Fagus - Abies phase began. In the time interval 2540-1935 cal. BP Carpinus decreased and around 680–660 BP the montane forest was subjected to strong human impact. Before their expansion phases, the regional presence of Carpinus and Fagus is confirmed by sporadic finds around 8875 cal. BP, then by noticeable occurrences from about 7800 cal. BP onwards. Abies is observed later at 7545 – 7425 cal. BP. These occurrences suggest the existence of regional refuges situated in the deep valleys of the Apuseni Mountains during the last cold phases. They might have favoured the survival of some of the present tree species during the last glaciation. More generally, it can be assumed that during the Last Glacial and Lateglacial periods numerous refuges existed in the Carpathians. These isolated stands of trees favoured the colonisation during the Holocene. The local climatic conditions were the major limiting factors and explain many of the chronological differences observed.

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Regional comparisons The forest history of the Apuseni Mountains described above is similar to that of the surrounding countries (Ukraine, Bulgaria, Hungary, Czechia, Slovakia, Poland and Slovenia) (Fig. 1) There is no difference concerning the history of Quercus and Ulmus. Both trees were present in all these countries from the beginning of the Holocene as well as in the Apuseni Mountains around 10190 BP. Picea is present in Romania around 11165 – 10870 cal. BP (Farcas et al. 1999). It is also regularly observed from the beginning of the Holocene in pollen diagrams from Slovenia (Sercelj 1996; Culiberg and Sercelj 1996), Poland (Ralska-Jasiewiczowa and Latalowa 1996) as well as in Czechia and Slovakia (Zlatnicka dolina, Tojrohe Pleso, Vracov) (Rybnickova and Rybnicek 1996). In Southwestern Czechia it is present around 10970–10624 cal. BP and it increases around 9373–9044 cal. BP (Svobodova et al. 2001). From the observation of the pollen diagrams it seems that its maximal values are not synchronous. Carpinus is regularly found from the beginning of the Holocene in different parts of Bulgaria (Lake Suho Ezero 2, Kupena, Tschokljovo, Lake Sedmo Rilsko, Lake Ribno Banderishko, Lake Srebarna, etc; Bozilova et al. 1989, 1990, 1996; Tonkov and Bozilova 1992; Bozilova and Tonkov 2000; Lazarova and Bozilova 2001; Tonkov et al. 2002), in Hungary (Batorliget: Willis et al. 1995), and sporadically present before 7800 cal. BP in Ukraine (Dovjok, Orgeev, Kardashinski: Kremenetski 1991, 1995; Kremenetski et al. 1999). These early occurrences support the hypothesis of the existence of numerous regional glacial and lateglacial refuges. In the Apuseni Mountains hornbeam occurrs sporadically around 9450–8875 cal. BP (Ic Ponor). Its pollen is regularly present at Bergerie from ca 7800 cal. BP and its percentages increase considerably ca. 6400 cal. BP. This chronology is coherent with data from the Balkans (Willis 1994) but in the surrounding countries the expansion phase of Carpinus is not always synchronous. Fagus appears in the Apuseni Mountains ca. 9450–9200 cal. BP (Ic Ponor) as well as in Hungary, Slovenia, Czechia and Slovakia where it is observed around 10435, 8900 and before 7800 cal. BP, respectively. Recent investigations in Southwestern Czechia (Svobodova et al. 2001) show its presence around 6382–6290 cal. BP and a development shortly after. At Padis, Cimetière and Bergerie its expansion occurred ca 4500 cal. BP like in the Western Mediterranean (Jalut 1984; Jalut et al. 1982, 1998; Reille and Lowe 1993). In Slovenia, Czechia, Slovakia and Poland the expansion phases were not synchronous. They occurred around 8340, 7800, 6820 and 5360 cal. BP, respectively. In the Apuseni Mountains Abies is present around 6820 cal. BP (Ic Ponor) as well as in Czechia and Slovakia (Rybnickova and Rybnicek, 1996) and in Poland (Ralska-Jasiewiczowa and Latałowa 1996). Its pollen is established earlier in Slovenia (>7800 cal. BP) (Sercelj 1996; Culiberg and Sercelj 1996). In Southwestern Czechia pollen of Abies is noticed around 10970 – 10624 cal. BP with a subsequent regular presence since 9372 – 9044 cal. BP (Svobodova et al. 2001). The expansion phases dated at 4030 cal. BP at Bergerie and Padis, around 4500 cal. BP in Czechia and Slovakia (Rybnickova and Rybnicek 1996), and at 5110 – 4500 BP at Iezerul Calimani and Taul Zanogutii (Farcas et al. 1999), as well as the

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contemporaneous vast expansion of Fagus emphasizes the importance of the 5110 – 4030 cal. BP time interval for the establishment of the mountain forests. The comparisons with the vegetation changes occurring at the same time in the Western Mediterranean area (Jalut et al. 1997, 2000) show that these changes were essentially controled by climate. Bearing in mind that human impact has increased around 5100 – 4500 cal. BP we could consider like Willis (1994) that for Romania and the surrounding areas this time interval was a critical period for the development of the present-day landscape. At a geographical scale which encompasses a large part of the Balkans (Willis 1994) and covers a great diversity of ecological situations, correspondances between the major vegetation changes in the Balkans and in the Apuseni Mountains can be observed. Between 10190 and 8875 cal. BP Pistacia expanded in the southern parts of the Balkans and Quercus and Ulmus developed in the Apuseni Mountains. Between 7800 and 5730 cal. BP Carpinus betulus and Fagus appeared in the Balkans while in the Apuseni Mountains they extended ca. 6400 cal. BP and 4500 cal. BP, respectively. Important changes occurred in the landscape of the Balkans around 5100 cal. BP contemporaneous with the expansion of Fagus, an increase in Poaceae and the spread of ruderal communities in the Apuseni Mountains. This correlation of the natural environmental and vegetation changes suggests that they were determined by climatic changes, and possibly that such changes influenced the human activities. Human impact The first evidence for the presence of humans is visible in the pollen diagrams of Ic Ponor around 7800 cal. BP (Bodnariuc 2000; Bodnariuc et al. 2002). At that time Chenopodiaceae and Asteroideae became more frequent. This early impact is not surprising when considering the situation of the site along a valley allowing an easy access to the flat areas of mid elevation. From the available archaeochronological data this first presence might be attributed to the first Neolithic occupations in Transylvania (Gura Baciului, Ocna Sibiului, Starcevo - Cris III - IV Cultures) dated between 7850 and 7350 cal. BP (Lazarovici 1993; Demoulle 1998; Mantu 1998). The settlements of these people were located less than 100 km from the studied area, the anthropogenic indicators suggesting that at that time groups had already begun to travel across the mountain. At Bergerie, during the same period, anthropogenic indicators such as Cichorioideae and Rumex increased ca. 7600 cal. BP. The local impact was of limited importance. The sedimentation rate which was 0.6 mm/yr between ca. 7800 cal. BP and 7600 cal. BP decreased to only 0.17 mm/yr between 7600 and 4570 cal. BP. The age of this first palynological evidence of Romanian Neolithic husbandry coincides with the presence of numerous dated archaeological sites in the Balkans between 8900 and 6800 cal. BP (Willis 1994; Willis and Bennett 1994) and with the earliest Neolithic 14C dates from the Northern Balkans (8350–7800 cal. BP) (Edwards et al. 1996). In Northeastern Bulgaria, at Lake Durankulak (Bozilova and Tonkov 1998), the first evidences of human occupation are recorded around 7300–6200 cal. BP.

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Fig. 8. Anthropogenic indicators in the Apuseni Mountains.

The first Cerealia pollen is noticed at Ic Ponor I during the Neolithic, around 7100 cal. BP (6190±90 BP). At the same time Artemisia and Poaceae are more abundant. During the same period, several groups are known in Transylvania near the studied zone: Cheile TurziiLumea Noua Complex and Turdas Groups (Mantu 1998). Around 5200–4500 cal. BP at Cimetière and Bergerie, the percentages of Poaceae and ruderal communities (Chenopodiaceae, Rumex, Urticaceae) increase as well as those of Carpinus and Fagus. At Bergerie during the period 4570–4100 cal. BP the sedimentation rate was 0.71 mm/yr This value is higher compared to the previous 7600–4570 cal. BP (0.17 mm/yr) and subsequent 4100–1935 cal. BP (0.14 mm/yr) periods. The interpretation of these changes is difficult. They might be due to the climatic variations which concerned this period in Europe and determined the expansion of beech (Huntley and Prentice 1988; Huntley et al. 1989; Huntley 1990a and b; Kelly and Huntley 1991; Gardner and Willis 1999). But the consequences of the human impact should not be underestimated. In the Pyrenees, at mid and low altitudes (Jalut, 1984, 1998; Jalut et al. 1982, Kenla and Jalut 1979) as well as in the plains of Central Europe (Küster 1997), and in the Romanian mountains, the abundance of Fagus in the forests may be partly related to the successive cuttings of fir, oak or spruce forests. At Bergerie, when deforestation increased from 4100 to 1935 cal. BP, the sedimentation rate decreased (0,143 mm/yr), and then started to increase again between

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ca. 1935 cal. BP and 680 cal. BP (0,24 mm/yr). These fluctuations render the interpretation difficult. At Padis, despite the favourable topographic conditions, there is no clear palynological evidence for an early strong local human impact and the sedimentological study of the core is not informative. The sedimentation rate keeps low values along the entire core (between 0.09 and 0.14 mm/yr from level 90 to level 35). Only the recent Sphagnum peat shows a higher rate of 0.78 mm/yr. At Cimetière the use of the sedimentological data might be more informative but the lack of dates does not allow calculation of the sedimentation rate. However, around 1935 cal. BP a relationship exists between the abundance in anthropogenic indicators, the decrease in AP/T values and the presence of thin layers of sand in the peat. They might be the consequence of erosion processes related to deforestation. The contemporaneous decline in the pollen concentration reinforces the hypothesis of a strong human impact on the landscape. In the three sites between ca. 4500 and 3200–2750 cal. BP the forest cover remained stable. Then it began to regress. The decrease in AP values is correlated to a rise in Poaceae, Chenopodiaceae and Plantago species. At Padis and Bergerie, around 2750–2550 cal. BP, the development of Poaceae and the spread of ruderal communities (Artemisia, Chenopodiaceae, Rumex, Urticaceae, Plantago) demonstrate an increase of human activities. They rose around 1935 BP and 695–660 cal. BP (note the presence of Cerealia at Cimetière). These periods correspond to decreases in AP values (Bergerie, Cimetière, Padis). Humans gradually spread into the mountain (Obelic et al. 1998). At the same time the human impact affected elevations between 1000 m and 1400 m and the lower zones. Thus the decrease in the percentages and pollen concentration of Carpinus, Quercus, Ulmus and Tilia is synchronous with an increase in the anthropogenic indicators and possibly reflects the destruction of the Querceto - Carpinetum. The massive forest clearance during the last century is shown by the fall in AP values and the higher Poaceae percentages abundant in the upper levels of most peat bogs. In the studied area the present scarcity of Abies and the noticeable spread of Fagus are probably the consequences of this deforestation. At some places such as Ic Ponor the pollen analysis of the fifteen uppermost centimeters of Sphagnum peat shows a correlation between the forest destruction and the extension of the cultivated areas. Cerealia pollen is regularly observed and in the surface samples pollen of Secale, Fagopyrum, Centaurea cyanus, Plantago lanceolata, Plantago coronopus and Fabaceae are well represented. The abundance of Onobrychis-type pollen testifies to cultivated zones, fallow land and pathways in the close vicinity (Figs. 3 and 4). The comparison of the data from the Apuseni Mountains with the available pollen records from the Romanian Carpathians reveals an early human impact on the montane vegetation. In the Eastern Carpathians, at Iezerul Calimani (Farcas et al. 1999), the regular presence of Plantago is only noticed from ca. 3430 cal. BP and is synchronous with the expansion of Fagus. High values of Juglans are dated around 1580 cal. BP after a strong

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decrease in Pinus values and an increase in Poaceae, Asteroideae and Carpinus pollen. The latter might have been favoured by the local deforestations. In the Banat Mountains the first presence of humans is recorded earlier, around 4450 cal. BP. It is characterized by the presence of pollen grains of Triticum-type and Plantago lanceolata and by an increase in charred particles (Rösch and Fischer 2000). Subsequently, during the Iron Age around 4650–4250 cal. BP, increases in Plantago, cereals and charcoals are recorded. An abundance of charcoal particles is noticed from the late medieval to the modern period. CONCLUSIONS After their establishment between 11200 and 10190 cal. BP, Picea and Corylus were dominant up to 6450 cal. BP. The expansion phases of Carpinus, Fagus and Abies began at ca. 6450 BP, 4500 BP and 4100 cal. BP, respectively. Finds of pollen of these trees are recorded from about 7800 cal. BP (Bodnariuc 2000; Bodnariuc et al. 2002). These palynological investigations demonstrate the early role of humans on the forest. The first evidence for settlements is recorded around 7800 cal. BP, then at 7570 and 7425 cal. BP (Fig. 8). The first Cerealia pollen is found ca. 6820 cal. BP. During the Bronze Age, between about 5100 and 3200–2750 cal. BP, the human impact remained stable and of limited importance. Then it increased at all elevations particularly around 1935 and 695–660 BP. The most extensive forest destructions occurred during the last century. At mid elevation beech was favoured at the expense of Picea during the recent recolonisation phases. ACKNOWLEDGEMENTS This research was supported by the Ministère Français de l’Education Nationale, de la Recherche et de la Technologie “Réseau Formation Recherche Pays Europe Centrale et Orientale – Réseau Franco - Roumain” (Contract 4778836 A), Coordinator Dr. Ch. Causse, and by the Ministère Français des Affaires Etrangères (Grant n° 268230C). We express our gratitude to Dr. E. Silvestru (Emil Racovita Speological Institute, Cluj Napoca, Romania), for his determining help during the field work; to Pr. L. Ghergari, for her support at the Babes - Bolyai University of Cluj Napoca; to Pr. Dr. C. Radulescu, Speological Institute of Bucharest for his support and his welcome; Dr. M. Bakalowicz and Dr. A. Mangin for their useful comments on the field; to Dr. M. Thinon for determination of Picea charcoal, Ms D. Dejean for her help in bibliography. Thanks are due to M. Arnold, head of UMS 2004 Tandetron, L.S.C.E., Gif sur Yvette and to the L.S.C.E. Radiocarbon team, especially M. Paterne, N. Tisnerat, E. Kaltnecker, C. Noury and C. Hatté.

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© PENSOFT Publishers The development Sofia - Moscow

Spassimir Tonkov (ed.) 2003 of the late-glacial and Holocene diatomAspects floraof in Lakeand ... Palaeoecology 171 Palynology Festschrift in honour of Elissaveta Bozilova, pp. 171-183

The development of the late-glacial and Holocene diatom flora in Lake Sedmo Rilsko (Rila Mountains, Bulgaria) André F. Lotter1 and Gabriele Hofmann2 1

Universiteit Utrecht, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, 3584 CD Utrecht, The Netherlands. E-mail: [email protected] 2 Hirtenstrasse 19, D-61479 Glashütten, Germany

Dedicated to Prof. Elissaveta Bozilova on the occasion of her 70th birthday ABSTRACT Diatom analyses were carried out on a 5-meter long sediment core from Sedmo Rilsko, a mountain lake at 2095 m a.s.l. in the Rila Mountains (Bulgaria). They show two distinct lateglacial and four Holocene diatom assemblage zones. The oldest three zones are characterized by periphytic, alkaliphilous to circumneutral diatoms, mainly Fragilaria species. These assemblages reflect well-buffered water conditions due to a high amount of clastic inwash. Around 8800 cal. BP a conspicuous change to acidobiontic Brachysira brebissonii assemblages took place, which reflects both stabilization of soils in the catchment by a denser vegetation cover and a decrease in alkalinity. At around 6350 cal. BP, after the expansion of coniferous trees in the catchment due to wetter conditions, the B. brebissonii abundance decreased substantially and erosional input increased slightly, leading to higher alkalinity in the water column. KEY WORDS: Diatoms – Mountain lakes – Catchment-lake interaction – Climate change

INTRODUCTION Mountain lakes have been shown to be sensitive indicators of past, present and future global change. In contrast to lowland lakes mountain lakes often register climate change directly (e.g. Battarbee et al. 2002b). Due to their location at higher elevations they are often not influenced by anthropogenic nutrient enrichment due to human activity in the catchment. Moreover, due to climatic conditions, at higher elevations the length of the open-water season largely determines the productivity in the water column (e.g. Catalan et al. 2002). Climatic conditions also have an influence on catchment processes, such as weathering and the erosion of minerals. These processes influence

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water chemistry and thus the aquatic ecosystem (e.g. Psenner and Schmidt 1992; Koinig et al. 1998). Whereas the development of the vegetation in the Bulgarian mountains is increasingly being unravelled (Bozilova et al. 1996; Bozilova and Tonkov 1994, 2000; Tonkov et al. 2002) there is still little information about the late-glacial and Holocene development of aquatic ecosystems and especially about the diatom flora. The present study was, on the one hand, aimed at understanding diatom assemblage changes in a Bulgarian mountain lake in relation to changes in climate and catchment vegetation. On the other hand, this study represents a first step towards a floristic characterization of the diatom flora of the Rila Mountains. MATERIAL AND METHODS Sedmo Rilsko is a cirque lake situated in the north-western region of the Rila Mountains in south-western Bulgaria. The lake lies at 2095 m a.s.l. in the lower subalpine belt. The hydrological catchment includes 3 km2 with a vegetation consisting of stands of Pinus mugo, Juniperus sibirica and open patches of herbaceous vegetation. Sedmo Rilsko is the lowermost of a set of seven connected cirque lakes. It has an open water area of 5.9 ha, a volume of 240000 m3 and a mean and maximum depth of 4.1 m and 11 m, respectively. The catchment geology consists of Palaeozoic metamorphic and intrusive rocks. In 1994 a 530 cm long sediment core was sampled with a square-rod piston sampler (Bozilova and Tonkov 2000) in the central part of the lake at a water depth of 8.25 m. Diatom samples of 0.5 cm3 were taken at 10 cm intervals along the sediment core. The topmost unconsolidated 50 cm of sediment were not available for this study. The samples were digested with hot 30% H2O2 and 10% HCl before the residue was embedded with Naphrax on permanent slides. A minimum of 400 valves per sample were counted at a magnification of 1000x and the floras of Krammer and Lange-Bertalot (1986, 1988, 1991a, 1991b), Lange-Bertalot and Moser (1994), Lange-Bertalot and Metzeltin (1996), and Krammer (2000) were used for identification. For loss-on-ignition (LOI) analyses about 1 g of dry sediment was combusted at 550 and 950°C following Heiri et al. (2001). LOI at 950°C, however, showed no detectable carbonate content. The biogenic silica concentration of the sediment was determined by the wet chemical dissolution photometric technique after de Master (1981). The diatom diagram was zoned numerically using optimal sum-of-squares partitioning (Birks and Gordon 1985) as implemented in the program ZONE (Lotter and Juggins 1991). The significant number of diatom assemblage zones was assessed by using the broken stick model (Bennett 1996). To assess taxonomic richness in the diatom assemblages, rarefaction analysis was carried out. Rarefaction analysis estimates the number of taxa in a standardized sampling unit (Birks and Line 1992).

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RESULTS AND DISCUSSION According to Bozilova and Tonkov (2000) the lowest part of the core consists of lateglacial sediments of pre-Allerød age, whereas they attribute the sediment between 437 and 413 cm to the Younger Dryas cold phase. The chronology of the sediment core is based on three calibrated AMS-radiocarbon dates, the pollen-inferred onset of the Younger Dryas and the core top (Bozilova and Tonkov 2000) that were used in a depth-age model (Fig. 1). According to this depth-age model the sediment accumulation rates were low during the late-glacial and early Holocene (Fig. 1) and increased rapidly ca. 8000 cal. years ago. Organic matter contents of between 10 and 25% characterize the sediment below ca. 400 cm. In the early Holocene, however, the amount of organic matter steadily increases from ca. 25 to over 50%. The LOI results (Fig. 1), as well as the palaeobotanical evidence (Bozilova and Tonkov 2000), suggest a change from predominantly allochthonous clastic sediment to autochthonous organic sediment in connection with increasing vegetation cover in the catchment of Sedmo Rilsko. The highly organic Holocene deposits mainly represent the result of the productivity in the water column (see e.g. Battarbee et al. 2002a). Optimal sum of squares zonation revealed six significant diatom assemblage zones. These zones are mainly characterized by changes in the relative abundance of small Fragilaria species (Fig. 2). During zone D-1 (pre-Allerød, according to Bozilova and Tonkov 2000) the diatom assemblages are dominated by Fragilaria pinnata, which is typical for late-glacial (e.g. Round 1964; Haworth 1969) or arctic and alpine environments (e.g. Lotter et al. 1997, 1999). Zone D-2 (Allerød to beginning of Younger Dryas) is characterized by periphytic diatoms such as Fragilaria neoproducta and Gomphonema parvulum. But the centric planktonic Cyclotella radiosa also occurs with relative abundances of more than 30%, showing a marked decrease during the Younger Dryas cold phase. This high abundance of a planktonic diatom is in contrast to the results of many other late-glacial diatom studies but suggests that favourable climatic conditions for the development of a planktonic flora already existed. In zone D-3 (Younger Dryas to ca. 8800 cal. BP) other periphytic taxa such as Achnanthes minutissima, Nitzschia sp. and Brachysira neoexilis dominate the assemblages (Fig. 2). On the basis of the high abundance of alkaliphilous to circumneutral diatoms in assemblage zones D-1 to D-3 it can be concluded that the lake must have had a higher alkalinity than today and was thus well buffered. The sparse late-glacial and early Holocene vegetation cover in its hydrological catchment (Bozilova and Tonkov 2000) favoured soil erosion as evidenced by the low LOI content (Fig.1). This erosional input also brought cations into the lake, which increased its alkalinity. Diatom assemblage zone D-4 (ca. 8800 to ca. 6350 cal. BP) is characterized by the massoccurrence of B. brebissonii and the decline of other periphytic diatoms (Fig. 2). Based on its occurrence many authors characterize this species as a diatom indicative of oligotrophic and acid lakes (e.g. van Dam et al. 1994; Bigler and Hall 2002). Other genera with affinities to acid waters such as Eunotia and Pinnularia also increase markedly during this zone, indicating that alkalinity of the water decreased markedly during zone D-4. This was most likely due

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Fig. 1. Depth-age model (note that the lowermost date is inferred from palynological data), loss-onignition (LOI) data representing the amount of organic sediment, biogenic silica (representing diatom productivity) and rarefaction analysis (representing diatom diversity) for a sediment core from Sedmo Rilsko (Rila Mountains).

to soil stabilisation (and thus less erosion) by increased vegetation cover in the catchment of Sedmo Rilsko, which is also evidenced by the high LOI content at values above 50% (Fig. 1). For this period Bozilova and Tonkov (2000) inferred a vegetation characterized by Betula pendula stands and groups of pine, green alder and willow. Taking the pollen curve of Tilia (Fig. 3, but also Ulmus, Acer, Quercus cerris, see Bozilova and Tonkov, 2000) as a proxy for the thermic climate, the Holocene climatic optimum would coincide with diatom assemblage zone D-4. Diatom assemblage zone D-5 (ca. 6350 to ca. 3300 cal. BP) is characterized by a substantial decline in B. brebissonii. Circumneutral and alkaliphilous Fragilaria species (F. construens, F. pseudoconstruens, F. exigua) as well as A. minutissima increase again during this zone (Fig. 2), whereas the acidophilous taxa remain present at lower percentages. At the onset of D-5 there is evidence in the pollen diagram for the expansion of several coniferous trees such as Pinus and Abies (Fig. 3). Bozilova and Tonkov (2000) interpret this as an uphill expansion of the coniferous forest belt due to an increase in precipitation and consequently also of humidity. This change in the precipitation regime may have resulted in an increased erosional input into the lake. The decrease in LOI content (Fig. 1) contemporaneous with the pollen signal confirms that this was the case. The enhanced allochthonous clastic input is likely to have led to higher alkalinity and buffering capacity in the lake, thus favouring circumneutral and alkaliphilous diatoms again. A second decrease in LOI is observed starting at ca. 220 cm sediment depth (ca. 4500 cal. BP), which coincides with an increase in the acidobiontic B. brebissonii, followed by peaks of the acidophilous Aulacoseira alpigena and A. cf. distans, and eventually by an increase

Fig. 2. Diatom diagram from a core from Sedmo Rilsko (Rila Mountains) showing the percentages of the major diatom taxa (minimum 5 occurrences, minimum relative abundance of 2%, for a detailed list of diatom taxa see appendix) and indicating the radiocarbon dates (given in conventional radiocarbon years BP). Note that the top 50 cm (past ca. 1000 years) of the core are not shown.

10170±60

6480±80

4005±50

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Fig. 3. Comparison of major diatom taxa with selected pollen types (data from Bozilova and Tonkov 2000) from the same sediment core of Sedmo Rilsko (Rila Mountains). Note that the top 50 cm (past ca. 1000 years) of the core are not shown.

176 André F. Lotter and Gabriele Hofmann

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of the circumneutral Achnanthes minutissima (see Fig. 2). It is unclear whether this change in sediment and diatom assemblages was caused by increased erosional input triggered by a wetter climate or by a decrease in in-lake productivity caused by a cooler climate. However, the diatom productivity as estimated by the biogenic silica concentration (Fig. 1) shows a twofold increase suggesting that the diatom productivity was silica-limited. Additional input of silica from the catchment may have allowed higher diatom productivity. Concurrent with the LOI decrease around 220 cm the pollen curve of Fagus increases (Fig. 3) giving evidence for the regional expansion of this tree. It is rather unlikely that beech grew in the catchment of Sedmo Rilsko. Given the coincidence in diatom assemblage change (e.g. increases in A. alpigena, A. cf. distans, Pinnularia microstauron and a decrease in A. minutissima) and the expansion of beech, it is likely that its expansion in the Rila Mountain region around 4500 cal. BP. was climatically triggered. The topmost diatom assemblage zone D-6 (since ca. 3300 cal. BP) is dominated by the same set of diatoms as in D-3. However, according to the strongly increased biogenic silica content (Fig. 1) diatom productivity during this zone was at its peak. Taxonomic diversity of the diatom assemblages in Sedmo Rilsko as assessed by rarefaction analysis (Fig. 1) shows low pre-Allerød values (D-1), intermediate diversities during the lateglacial and early Holocene (D-2 to D-4) and a higher diversity throughout the middle and late Holocene (D-5 and D-6). It is noteworthy that taxonomic diversity, as well as biogenic silica concentrations (Fig. 1), are generally lower during phases of increased occurrences of acidophilous and acidobiontic diatoms (D-4, second part of D-5) such as B. brebissonii. Unfortunately, we cannot compare the late-glacial and Holocene development of diatom assemblages with the modern state and assess the amount and effect of anthropogenic acidification on the lake during the past century. ACKNOWLEDGEMENTS We would like to thank Prof. Elissaveta Bozilova for providing the sediment samples for diatom analysis and Dr. Spassimir Tonkov for generously making the pollen data of Sedmo Rilsko accessible. We gratefully acknowledge Dr. Kurt Krammer for his taxonomical help, Dr. Sheila Hicks for her linguistic help and D. Siegrist for processing the diatom samples and carrying out the LOI and biogenic silica analyses. REFERENCES Battarbee RW, Grytnes JA, Thompson R, Appleby P, Catalan J, Korhola A, Birks HJB, Heegaard E, Lami A (2002a) Comparing palaeolimnological and instrumental evidence of climate change for remote mountain lakes over the last 200 years. J Paleolimn 28: 161-179. Battarbee RW, Thompson R, Catalan J, Grytnes JA, Birks HJB (2002b) Climate variability and ecosystem dynamics of remote alpine and arctic lakes: the MOLAR project. J Paleolimn 28: 1-6.

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Bennett KD (1996) Determination of the number of zones in a biostratigraphical sequence. New Phytol 132: 155-170. Bigler C, Hall RI (2002) Diatoms as indicators of climatic and limnological change in Swedish Lapland: a 100-lake calibration set and its validation for paleoecological reconstructions. J Paleolimn 27: 79-96. Birks HJB, Gordon AD (1985) Numerical methods in Quaternary pollen analysis. Academic Press, London. Birks HJB, Line JM (1992) The use of rarefaction analysis for estimating palynological richness from Quaternary pollen-analytical data. Holocene 2: 1-10. Bozilova E, Filipova M, Filipovich L, Tonkov S (1996) Bulgaria. In: Berglund BE, Birks HJB, Ralska-Jasiewiczowa M, Wright HE (eds) Palaeoecological Events During the Last 15 000 Years. Regional Synthesis of Paleoecological Studies of Lake and Mires in Europe. John Wiley & Sons, Chichester, pp 701-728. Bozilova E, Tonkov S (1994) The postglacial distribution patterns of Abies in Bulgaria. Diss Bot 234: 215-223. Bozilova E, Tonkov S (2000) Pollen from Lake Sedmo Rilsko reveals southeast European postglacial vegetation in the highest mountain area of the Balkans. New Phytol 148: 315-325. Catalan J, Vetura M, Brancelj A, Granados I, Thies H, Nikus U, Korhola A, Lotter AF, Barbieri A, Stuchlik E, Lien L, Bitusik P, Buchaca T, Camarero L, Goudsmit GH, Kopacek J, Lemcke G, Livingstone DM, Müller B, Rautio M, Sisko M, Sorvari S, Sporka F, Strunecky O, Toro M (2002) Seasonal ecosystem variability in remote mountain lakes: implications for detecting climatic signals in sediment records. J Paleolimn 28: 25-46. de Master DJ (1981) The supply and accumulation of silica in the marine environment. Geochimica Cosmochimica Acta 45: 1715-1732. Haworth EY (1969) The diatoms of a sediment core from Blea Tarn, Langdale. J Ecol 57: 427-441. Heiri O, Lotter AF, Lemcke G (2001) Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results. J Paleolimn 25: 101-110. Koinig KA, Schmidt R, Sommaruga-Wögrath S, Tessadri R, Psenner R (1998) Climate change as the primary cause for pH shifts in a high alpine lake. Water, Air, and Soil Pollution 104: 167-180. Krammer K (2000) The genus Pinnularia. Diatoms of Europe 1: 1-703. Krammer K, Lange-Bertalot H (1986) Bacillariophyceae. 1. Teil: Naviculaceae. Gustav Fischer Verlag, Stuttgart. Krammer K, Lange-Bertalot H (1988) Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. Gustav Fischer Verlag, Stuttgart. Krammer K, Lange-Bertalot H (1991a) Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. Gustav Fischer Verlag, Stuttgart. Krammer K, Lange-Bertalot H (1991b) Bacillariophyceae. 4. Teil: Achnanthaceae, kritische Ergänzungen zu Navicula (Lineolatae) und Gomphonema. Gesamtliteraturverzeichnis Teil 1-4. Gustav Fischer Verlag, Stuttgart. Lange-Bertalot H, Metzeltin D (1996) Indicators of oligotrophy. Iconographia Diatomologica 2: 1-390.

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Lange-Bertalot H, Moser G (1994) Brachysira - Monographie der Gattung. Bibliotheca Diatomologica 29: 1-212. Lotter AF, Birks HJB, Hofmann W, Marchetto A (1997) Modern diatom, cladocera, chironomid, and chrysophyte cyst assemblages as quantitative indicators for the reconstruction of past environmental conditions in the Alps. I. Climate. J Paleolimn 18: 395-420. Lotter AF, Juggins S (1991) POLPROF, TRAN and ZONE: programs for plotting, editing and zoning pollen and diatom data. INQUA-Subcommission fot the study of the Holocene. Working Group on Data-Handling Methods. Newsletter 6: 4-6. Lotter AF, Pienitz R, Schmidt R (1999) Diatoms as indicators of environmental change near Arctic and Alpine treeline. In: Stoermer EF, Smol JP (eds) The diatoms: application to the environmental and earth sciences. Cambridge Univ Press, Cambridge, pp 205-226. Psenner R, Schmidt R (1992) Climate-driven pH control of remote alpine lakes and effects of acid deposition. Nature 356: 781-783. Round FE (1964) The diatom sequence in lake deposits: some problems of interpretation. Verh Intern Verein Limn 15: 1012-1020. Tonkov S, Panovska H, Possnert G, Bozilova E (2002) The Holocene vegetation history of Northern Pirin Mountain, southwestern Bulgaria: pollen analysis and radiocarbon dating of a core from Lake Ribno Banderishko. Holocene 12: 201-210. van Dam H, Mertens A, Sinkeldam J (1994) A coded checklist and ecological indicator values of freshwater diatoms from the Netherlands. Netherlands J Aquatic Ecol 28: 117-133.

APPENDIX Diatom taxa encountered in the late-glacial and Holocene sediments of Lake Sedmo Rilsko (2095 m asl). Achnanthes - altaica (PORTEZKY) CLEVE-EULER - daonensis LANGE-BERTALOT - didyma HUSTEDT - flexella (KÜTZING) BRUN - helvetica (HUSTEDT) LANGE-BERTALOT - lanceolata ssp. frequentissima LANGE-BERTALOT - lapidosa KRASSKE - levanderi HUSTEDT - linearioides (LANGE-BERTALOT) LANGE-BERTALOT - marginulata GRUNOW - minutissima KÜTZING - minutissima var. scotica (CARTER) LANGE-BERTALOT - oestrupii (CLEVE-EULER) HUSTEDT - saccula CARTER

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- subatomoides (HUSTEDT) LANGE-BERTALOT - suchlandtii HUSTEDT - ventralis (KRASSKE) LANGE-BERTALOT Amphora - pediculus (KÜTZING) GRUNOW Aulacoseira - alpigena (GRUNOW) KRAMMER - cf. distans (EHRENBERG) SIMONSEN - valida (GRUNOW) KRAMMER Brachysira - brebissonii ROSS - neoexilis LANGE-BERTALOT Cavinula (Navicula sensu lato) - pseudoscutiformis (HUSTEDT) MANN & STICKLE Chamaepinnularia (Navicula sensu lato) - mediocris (KRASSKE) LANGE-BERTALOT - schauppiana LANGE-BERTALOT & METZELTIN - soehrensis var. hassiaca (KRASSKE) LANGE-BERTALOT Cocconeis - placentula EHRENBERG Cyclotella - radiosa (GRUNOW) LEMMERMANN Cymbella - affinis KÜTZING - cymbiformis AGARDH - elginensis KRAMMER - gracilis (EHRENBERG) KÜTZING - hebridica (GRUNOW) CLEVE - helvetica KÜTZING - microcephala GRUNOW - naviculiformis (AUERSWALD) CLEVE - perpusilla CLEVE-EULER - reichardtii KRAMMER

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- silesiaca BLEISCH - subcuspidata KRAMMER Diadesmis (Navicula sensu lato) - gallica var. perpusilla (GRUNOW) LANGE-BERTALOT Diatoma - mesodon (EHRENBERG) KÜTZING Eunotia - bilunaris (EHRENBERG) MILLS - diodon EHRENBERG - exigua (BRÉBISSON) RABENHORST - fallax A. CLEVE - glacialis MEISTER - implicata NÖRPEL et al. - incisa GREGORY - minor (KÜTZING) GRUNOW - nymanniana GRUNOW - paludosa GRUNOW - praerupta EHRENBERG - rhomboidea HUSTEDT Fragilaria - arcus KÜTZING - bicapitata A. MAYER - capucina var. gracilis (OESTRUP) HUSTEDT - capucina var. rumpens (KÜTZING) LANGE-BERTALOT - construens f. venter (EHRENBERG) HUSTEDT - exigua GRUNOW - nanana LANGE-BERTALOT - neoproducta LANGE-BERTALOT - oldenburgioides LANGE-BERTALOT - opacolineata LANGE-BERTALOT - parasitica var. subconstricta GRUNOW - pinnata EHRENBERG - pseudoconstruens MARCINIAK - robusta (FUSEY) MANGUIN - spec. Nr. 5 Julma Ölkky - tenera (W. SMITH) LANGE-BERTALOT

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Frustulia - rhomboides (EHRENBERG) DE TONI - rhomboides var. saxonica (RABENHORST) DE TONI Gomphonema - acuminatum EHRENBERG - clavatum EHRENBERG - gracile EHRENBERG - hebridense GREGORY - parvulum var. exilissimum GRUNOW - pumilum (GRUNOW) REICHARDT & LANGE-BERTALOT - sphenovertex LANGE-BERTALOT & REICHARDT - truncatum EHRENBERG Luticola (Navicula sensu lato) - mutica (KÜTZING) MANN Navicula - angusta GRUNOW - begerii KRASSKE - cryptocephala KÜTZING - exilis KÜTZING - cf. fluens HUSTEDT - laevissima KÜTZING - levanderii HUSTEDT - minima GRUNOW - notha WALLACE - pseudolanceolata LANGE-BERTALOT - pseudoventralis HUSTEDT - radiosa KÜTZING Naviculadicta (Navicula sensu lato) - absoluta (HUSTEDT) LANGE-BERTALOT - bryophila (PETERSEN) LANGE-BERTALOT - digituloides LANGE-BERTALOT - digitulus (HUSTEDT) LANGE-BERTALOT - elorantana LANGE-BERTALOT - fennica (HUSTEDT) LANGE-BERTALOT - schmassmannii (HUSTEDT) LANGE-BERTALOT - subtilissima (CLEVE) LANGE-BERTALOT

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Neidium - ampliatum (EHRENBERG) KRAMMER - nov. spec. 1 (cf. hercynicum A. MAYER) - nov. spec. 2 (cf. iridis (EHRENBERG) CLEVE) Nitzschia - acidoclinata LANGE-BERTALOT - alpina HUSTEDT - angustata GRUNOW - gracilis HANTZSCH - inconspicua GRUNOW - perminuta (GRUNOW) M. PERAGALLO - recta HANTZSCH - spec. Nr. 1 Julma Ölkky Pinnularia - borealis EHRENBERG - macilenta EHRENBERG - microstauron (EHRENBERG) CLEVE - microstauron var. rostrata KRAMMER - schoenfelderi KRAMMER - silvatica PETERSEN - subanglica KRAMMER - tirolensis (METZELTIN & KRAMMER) KRAMMER Sellaphora (Navicula sensu lato) - pupula (KÜTZING) MERESCHKOWSKY Stauroneis - anceps EHRENBERG - phoenicenteron (NITZSCH) EHRENBERG Stenopterobia - delicatissima (LEWIS) BRÉBISSON Tabellaria - flocculosa (ROTH) KÜTZING

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© PENSOFT Publishers Sofia - Moscow

Spassimir Tonkov (ed.) 2003 A palynological study in the Beles Mountains, Northern Greece 185 Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 185-197

A palynological study in the Beles Mountains, Northern Greece Nikolaos Athanasiadis*, Achilles Gerasimidis and Sampson Panajiotidis Institute of Forest Botany and Geobotany, Department of Forestry and Natural Environment, Aristotelian University of Thessaloniki, P.O. Box 270, GR- 54 124 Thessaloniki, Greece * E-mail: [email protected]

ABSTRACT A palynological study was conducted on a core collected from a peat bog (1400 m a.s.l) in the Beles Mountains, Northern Greece. The radiocarbon dates indicated that the analysed sediments were accumulated during the last 650 years. Despite that the coniferous forests, especially Pinus, are rather restricted in their present day distribution, they constituted the dominant component of the forest vegetation until the mid-16th century. During the period covered by the pollen diagram Fagus played an important role in the forest composition. The beech communities expanded from the late 17th century until the mid-19th century. This event is also registered in pollen diagrams from other mountainous regions in Greece suggesting that favourable climatic conditions prevailed for the growth of beech. The continuous human presence and activity (mainly stock-breeding) are clearly identified throughout the pollen diagram. KEY WORDS: Pollen analysis – Vegetation history – Fagus – Pinus – Beles Mountains – Northern Greece

INTRODUCTION Data on the vegetation history in a mountainous region could be obtained from palynological studies carried out in neighbouring low-altitudinal sites as the pollen diagrams comprise also elements of regional origin. However, in such diagrams the low-altitudinal vegetation zones are better reflected (Bottema 1979). The vegetation history of the mountainous regions is more reliably reconstructed when based on pollen diagrams from these regions (Gerasimidis and Athanasiadis 1995). Only a small number of the recent palynological studies in Greece derived from cores collected from mountainous areas (Fig. 1). One such investigation was carried out in Central Greece (Athanasiadis 1975), another one in Western Greece (Willis 1992), and five in

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Fig. 1. Map of Greece showing sites of coring : a) current site of investigation (Beles Mts.), b) Lake Doirani and c) 1-7 mountainous regions (1 Rhodopi, 2 Lailias, 3 Paiko, 4 Voras, 5 Pieria, 6 Rezina, 7 Pertouli).

Northern Greece (Gerasimidis 1985; Athanasiadis and Gerasimidis 1986, 1987; Athanasiadis et al. 1993). The results of pollen analysis of a core collected from a peat bog in the border mountainous range of Beles, and supplemented with radiocarbon dates, are presented in this paper. They contribute to the elucidation of the historical evolution of the vegetation during the last 650 years, and at the same time, provide new information on the human activity in this part of Northern Greece. Environmental setting Geography, geology and climate The Beles (Kerkini) Mountains, located north of the valley that binds Lake Kerkini and Lake Doirani, runs in east-west direction along the border of Greece, Bulgaria

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30

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Mean monthly rainfall (mm)

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and the F.Y.R.O.M. Its length is about 70 km and its width ranges between 10 and 15 km. The highest peak is Sideropetra (2031 m). The northern and southern slopes, especially those of the central part, are characterised by a very abrupt inclination (H.A.G.S. 1969). Geologically, the wider area of the mountain belongs to the Serbomacedonian massif of the Vertiskos series (Mountrakis 1985). The metamorphic rocks (amphibolites, gneiss and schist with layers of marble) are dominant while siliceous rocks, Mesozoic granite, granodiorite, monzonite and serpentines are present in a much smaller extent. Cones of rock deposits are found in the foothills of the south-central part (I.G.M.E. 1983). The nearest meteorological station on Greek territory is in Ano Theodoraki (442 m a.s.l) about 17 km south of the investigated area. The complete set of meteorological data covering a period of 27 years (1964-1990) was provided by the Territorial Amelioration Service of the Ministry of Agriculture. The mean annual temperature is 12.9°C and the mean annual precipitation is 476.7 mm. An ombrothermic diagram is provided on Figure 2. The area belongs to the “Cfa climatic type” according to Köppen’s classification (Flocas 1990). This “humid” climate type is characterised by long and very hot summers, mild winters and humid seasons. The dry period lasts about 3 months from July till September. The climatic conditions of the study area differ from those recorded by the meteorological station. The differences are more clearly expressed as the distance from the station increases and the altitude rises as well. The climate becomes more continental and can be characterised as “humid continental” with short warm summers and cold winters. Bioclimatically, the study area belongs to the humid bioclimatic floor with harsh winter. The bioclimate of such areas has a sub-mediterranean character (Mavrommatis 1980).

0 D J

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Fig. 2. Ombrothermic diagram of the meteorological station at Ano Theodoraki. ••••••• Mean monthly temperature curve; ––– Mean monthly rainfall curve.

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Modern vegetation The site of investigation, a small peat bog, is located above the present tree-limit of the beech (Fagus) forests of the Fagetalia zone. Deforested areas in south-eastern direction from the peat bog were planted with Pinus sylvestris about 25 years ago. The bog vegetation itself consists mainly of Carex, Poaceae and Sphagnum species. A more detailed description of the vegetation of the Beles Mountains can be found in several publications (Stojanoff 1921; Mattfeld 1927; Athanasiadis et al. 2000). Here follow some general remarks on the present vegetation thus providing a potential base for comparison with the past vegetation as archived in the peat sediments. According to Regel (1937) the Beles Mountains belongs to the Balkan mountainous type and is of a typical sub-mediterranean character. The most common trees and shrubs in the lowermost vegetation zone (Quercetalia pubescentis) up to 1000 (1100) m a.s.l. are Quercus coccifera, Quercus pubescens, Carpinus orientalis, Fraxinus ornus, Quercus frainetto, Quercus dalechampii, Pistacia terebinthus, Juniperus oxycedrus, Phyllirea media and Paliurus spina-christi. In the northeastern part grows Castanea sativa. In the beech forests between 1000 (1100) and 1600 (1700) m a.s.l. Acer pseudoplatanus, A. platanoides, Betula pendula, Populus tremula, Salix caprea, Ilex aquifolium, Taxus baccata and Carpinus betulus also occur. Pure coniferous forests are totally absent and only in the eastern part of the mountain and close to Ochiro scattered groups of Abies borisii-regis mixed with beech are found at c. 1150-1300 m a.s.l. The most common species above the tree limit are Juniperus nana, Bruckenthalia spiculifolia and Vaccinium myrtillus. In all vegetation zones, particularly at lower altitudes, the natural plant cover is seriously disturbed as a result of the anthropogenic activity. MATERIALS AND METHODS Coring and stratigraphy The core Beles, 225 cm deep, was collected from a peat bog (1400 m a.s.l.) with an area of about 500 m2. The exact co-ordinates of the site are 23°00′58′′E and 41°19′10′′N. The Table 1. Stratigraphic details of the core Beles. Depth (cm)

Stratigraphy

0 - 95 95 - 100 100 - 108 108 - 133 133 - 155 155 - 185 185 - 195 195 - 218 218 - 225

Peat Sand with plant detritus Peat Sand with plant detritus Sandy clay (sc) Dy Peat Dy Sandy clay (sc) Dy Sandy with plant detritus

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coring was done with a Dachnowski hand-operated equipment. The stratigraphy of the core is shown on Table 1. Pollen analysis A total of 24 samples was processed with KOH, HF and acetolysis (Faegri and Iversen 1989). The pollen sum (PS) used for the percentage calculations was based on arboreal (AP) and non-arboreal (NAP) taxa, excluding pollen of Cyperaceae, hydrophytes, spores of mosses and pteridophytes. The percentage pollen diagram was constructed using Tilia and Tilia-graph software (Grimm 1991). The diagram is divided into four pollen zones (Ba…B-d) (Fig. 3). Pollen taxa with low values or of less importance are not shown in the pollen diagram. A list of these taxa follows: AP: Platanus, Pistacia, Taxus, Populus, Cercis, Larix, Paliurus, Ilex aquifolium, Lonicera, Rhamnus; NAP: Liliaceae, Viola, Ephedra fragilis, Geranium, Pulmonaria-type, Heracleum-type, Sanguisorba/ Poterium-type Symphytum, Rhinanthus, Scabiosa, Malvaceae, Helianthemum, Teucrium, Dipsacus/ Knautia, Daphne; Aquatics, mosses and pteridophytes: Typha/Sparganium-type, Sphagnum, Ophioglossum, Lycopodium, Botrychium RESULTS Radiocarbon dating Two samples were submitted for radiocarbon dating. The results are presented on Table 2. The dates have been calibrated using the curves of Stuiver and Becker (1993). The midpoint of calibration is also calculated. The estimates from the radiocarbon measurements indicate a relatively stable sediment-accumulation rate of c. 2 yrs/cm and 3.6 yrs/cm for the time intervals 1450–1660 cal. AD and 1660 cal. AD–till present, respectively. The age of the bottom part of the profile is calculated by interpolation at c. 650 BP. The model was used to define the age of the zone boundaries. Pollen diagram Zone B-a (220-155 cm, 7 samples, AP:NAP=42:58). In the lowermost part of the diagram NAP shows higher values while AP ranges between 41% and 48%. Among the tree species, Pinus shows the highest percentages, ranging from 8% to 25% with a mean value (m.v.) of Table 2. Radiocarbon dates from the core Beles. Depth (cm) 92 - 94 184 - 185

14 C Lab N

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LuA-5050 LuA-5051

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(1565 - 1755) (1345 - 1555)

1660 AD 1450 AD

Fig. 3. Percentage pollen diagram for core Beles.

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Fig. 3. Continued.

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16%, and reaching a maximum at the transition to the next zone. The presence of Quercus (m.v. 11%) is considerable, although its curve follows a reverse course compared to Pinus. The percentage values of Quercus are higher in the bottom part of the zone (15%, level 210 cm) and gradually decline to 5%. The presence of Fagus pollen is continuous with 2-5%. Abies is rarely found with 0.5-1.5%. The rest of arboreal taxa with percentages above 1% are Carpinus orientalis/Ostrya 1-3% (m.v. 2%), Salix and Alnus with 1-6% (m.v. 3%) and 14% (m.v. 2%) respectively, with a maximum at the lowermost sample. Pollen of Poaceae demonstrates the highest percentages among the herbs with 14-35% (m.v. 26%). The frequency of Plantago lanceolata rises from 4% to 17% (m.v. 8%). On the contrary, pollen of Cichoriaceae is most common in the lowermost samples with 3-11% (m.v. 8%). Other herbs worth to mention are Asteraceae 3%, Caryophyllaceae 2%, Rumex 2%, Chenopodiaceae 1%, Fabaceae 1% and Artemisia 1%. Zone B-b (155-85cm, 8 samples, AP:NAP=40:60). In this zone the quantity of NAP increases with an exception at level 105 cm (AP=55%). Despite a decline in its representation, compared to the previous zone, Pinus remains as the dominant arboreal taxon with values around 8-13% (m.v. 12%). Pollen of Quercus also attains lower percentages of 5-10% (m.v. 7%). On the contrary, pollen of Fagus shows higher values reaching 4-13% (m.v. 6%). Among the rest of the arboreal taxa with values above 1% are: Carpinus orientalis/Ostrya (m.v. 3%), Salix 2%, Alnus 2% and Juniperus 1.5%. Poaceae continue to prevail among the herb taxa with pollen values from 20% to 30% (25%). The presence of Plantago lanceolata is quite considerable, ranging from 10% to 22%, with an exception at level 105 cm (4%). Other herb taxa of importance are Cichoriaceae 3%, Caryophyllaceae 3%, Asteraceae 2%, Artemisia 2%, Rumex 2%, Fabaceae, Lamiaceae, Cerealia, etc. Zone B-c (85-45 cm, 4 samples, AP:NAP=61:39). This is the only section of the diagram where AP exceeds NAP due to an increase of Fagus values. The most characteristic feature is the rise of Fagus curve from 15 to 51% (m.v. 26%) with a maximum at level 80 cm. Lower pollen percentages are recorded for Pinus 7-12% (m.v. 9%). Pollen of Quercus shows similar values like in the previous zone 4-10% (m.v. 8%). The arboreal taxa with values above 1% are: Carpinus orientalis/Ostrya 3.5%, Juniperus 3%, Salix 2%, Alnus 2% and Frangula 1.5%. Poaceae keep their dominant role among the herbs with pollen values of 16-30% (m.v. 21%). The presence of Plantago lanceolata is reduced to 2.5-9% (m.v. 4.5%). Minimal and maximal values are recorded at the beginning and the end of the phase respectively. Among the rest of the herbs, the participation of Cichoriaceae 2%, Artemisia 2%, Cerealia 1.5%, Rumex and Chenopodiaceae should be mentioned. Zone B-d (45-0 cm, 5 samples, AP:NAP=39:61). In this zone NAP prevails again. The pollen curve of Fagus declines to 5-9% (m.v. 6%). The presence of Quercus 4-7% (m.v. 6%) and Pinus 5-11% (m.v. 7%) is also reduced. The pollen curve of Juniperus increases up to 1012%. Pollen of Castanea is recorded in all samples reaching 1-2%. Other arboreal taxa with values above 1% are: Carpinus orientalis/Ostrya 2%, Alnus 2% and Salix 1%. The participation of Poaceae rises to maximal values of 26-42% (m.v. 33%). Higher pollen frequencies are recorded for Plantago lanceolata 3-10% (m.v. 8%) with a minimum in the uppermost sample.

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Pollen of Artemisia, Rumex, Chenopodiaceae, Fabaceae, Asteraceae, Ranunculaceae, Rubiaceae and Cerealia is also present. DISCUSSION Pollen diagram interpretation Zone B-a The lowermost part of the pollen diagram is assigned to 1350–1530 cal. AD. The forest vegetation appears to be restricted in distribution as shown by the values of the AP:NAP ratio, obviously due to anthropogenic interventions that have taken place in previous periods not covered by the diagram. Moreover, the pollen curves of the anthropogenic indicators show that these activities have not ceased. The low values of Cerealia pollen, compared to those of Plantago lanceolata, suggest that the human activity in the mountainous area of Beles was focused mainly on stock-breeding. In the upper part of the zone all anthropogenic indicators increase. The pollen curves of Cerealia, Rumex, Chenopodiaceae, Artemisia, as well as those of Juglans, Castanea and Vitis, indicate a profound human presence. The turning point in human activity is dated at 1450 cal. AD that coincides with the beginning of the Turkish occupation. Generally, the Turkish occupation caused the intensification of human activity in the mountainous regions where many inhabitants of the plains were forced to settle (Athanasiadis 1975; Gerasimidis 1995). The reduction of Quercus pollen values in relation to the other major components of the forest vegetation suggests that the anthropogenic interventions took place mainly at mid altitudes, and not in the nearest to the site of coring area. It also justifies the low percentages of most of the indicators of human activity as agriculture and stock-breeding. On the contrary, at higher altitudes the forest vegetation enlarged as proved by the behaviour of Pinus pollen curve. The pine forests gradually expanded and by the end of the phase Pinus has become the most important component in the forest vegetation of the Beles Mountains. The increase of Frangula alnus pollen values from the mid-point of the zone onwards suggests that this species has occupied the relatively humid areas within the pine forests. On the contrary, the pollen curves of both Alnus and Salix, which grew in similar habitats but obviously at lower altitudes, follow a parallel course with that of Quercus. By that time Fagus, in contrast to Pinus, was restricted in distribution although it gradually started to enlarge at the end of this zone. Abies remained as a limited component of the forest vegetation of the Beles Mountains and subsequently declined. The pollen diagram from the lowland Lake Doirani, located in the south-western foothills of the Beles Mountains, covers the last 5000 years and reveals a wider distribution of Abies up to 800 BC (Athanasiadis et al. 2000). According to the data from the pollen diagrams of Voras (Athanasiadis and Gerasimidis 1986), Paiko (Athanasiadis and Gerasimidis 1987), Rhodopi (Athanasiadis et al. 1993), Lailia and Pieria (Gerasimidis 1985), Abies has been an important

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component of the forest vegetation in the mountainous regions of Northern Greece prior to the Roman epoch (Gerasimidis 1995). Similar anthropogenic interferences in the fir forests took place by that time in the mountains of Bulgaria (Bozilova et al. 1995). However, Abies in the bulgarian part of the Beles (Belasitsa) Mountains did not play a significant role in the vegetation history during Late Subboreal and Subatlantic. A relevant palynological study recorded single Abies pollen grains in zone B1 (Late Subboreal) of the pollen diagram Belasitsa-2 (Panovska et al. 1990). Zone B-b This phase in the vegetation development spans the time interval from 1530 to 1685 AD. During this period the human activity in the study area, compared to the previous phase, continued to be steady and intensive. Most of the anthropogenic indicators are characterised by continuous curves and higher pollen percentages (Cerealia, Castanea, Juglans, Rumex and especially Plantago lanceolata). There is a characteristic presence of land-clearing or ‘bare-dry’ lands indicators like Juniperus, Asteraceae, Cichoriaceae, Caryophyllaceae, Pteridium and others. From this phase onwards Pinus ceased to be the dominant component of the forest vegetation. Taking into consideration the fact that Pinus pollen is ‘normally’ over-represented in the pollen diagrams, the percentages recorded reveal a significant reduction. A withdrawal of the Pinus tree-limit can be inferred by the simultaneous increase of Juniperus. This assumption is also supported by the presence of Ericaceae pollen originating from Bruckenthalia spiculifolia and Vaccinium myrtillus, both growing above the forest limit. Thus it can be also speculated that Juniperus nana contributes mainly to the pollen curve of Juniperus as this species is growing together with those mentioned above. The mixed oak forests were slightly reduced although the participation of Ulmus and especially Tilia in them has increased. Fagus seems to have expanded at high-altitudinal areas. Zone B-c During this phase which covered the period 1685–1865 cal. AD the vegetation of the Beles Mountains has changed. The forest cover expanded as shown by the values of the AP:NAP ratio. All pollen types related to agriculture, stock-breeding and land clearing manifest lower values, implying a temporal recession in human activity. In the case of the pollen percentages of Plantago lanceolata minimal values are established for the whole diagram. Nevertheless, almost all the anthropogenic indicators are represented by continuous curves, suggesting that human activity has never ceased. The expansion of the forest vegetation during this phase is mainly attributed to the beech forests. The values of Fagus fluctuate and two peaks are recorded while at the transition to the uppermost part of the zone a decline in the participation of Fagus is again observed.

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Although this short-term expansion of the beech forests probably coincided with a recession of human activity, it should be regarded mainly as a result of climatic change towards more humid conditions. These changes are justified by similar expansion of the beech forests at that time not only in the mountainous regions of Northern Greece (Voras, Paiko, Lailias and Rhodopi) but also in Central Greece (Pertouli). In the pollen diagram of Pertouli a peak in the distribution of the beech forests was dated at 1690 cal. AD (Athanasiadis 1975). On the contrary, the pollen diagram of Rezina (Epirus) in Western Greece (Willis 1992) shows that Fagus has played no important role in the forest vegetation history of this region. The increase in the percentage values of Quercus is followed by a slight rise of Castanea and Corylus. The course of Frangula alnus pollen curve corresponds to that of Fagus corroborating to the view that the climatic conditions have changed to more humid. Zone B-d The last phase of the vegetation history started after 1865 cal. AD and was characterised by a profound decline in the spread of the forest vegetation. The reduction of almost all arboreal pollen values suggests that the anthropogenic interventions took place in all vegetation zones. Deforested areas were colonized by herb vegetation and this process was favoured by Man as proved by the maximal values of Poaceae pollen. Despite the fact that the beech forests underwent their largest reduction, they remained as the dominant vegetation type of the Beles Mountains. Oak forests also declined. Simultaneously, Juniperus has recorded its highest values throughout the whole diagram. Besides a slight expansion of Juniperus species growing in the zone of the oak forests, this fact also indicates an expansion of Juniperus nana mainly as a result of the lowering of the upper limit of the beech forests. Finally, in the upper samples of this zone covering the recent decades, the shape of the vegetation reverts, as the forests partly recovered. Among the herb plants the highest reduction is observed for Plantago lanceolata. This species is a reliable indicator of (over)grazing, one of the main criterion for human activity, as stock-breeding has been the main occupation of the inhabitants of the Beles Mountains. The diagram implies that stock-breeding was drastically restricted during the last decades. Possible reasons might be that most of the inhabitants moved down to the lowlands, and also the measures taken by the Forest Service for the protection of the forests, especially a restriction of uncontrolled grazing. CONCLUSIONS 1. The human impact in the Beles Mountains has started long ago before 1350 cal. AD when the forest communities were already restricted in their distribution.

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2. Various activities of different intensity of the mountain inhabitants are traced throughout the period covered by the pollen diagram. Stock-breeding is registered as their main occupation. The peaks in human presence and activity coincide with historical events such as the beginning of the Turkish occupation. 3. The coniferous forests have played an important role in the past in contrast to their limited present day distribution in the Beles Mountains. Pinus has remained as the major component of these forests until the mid-16th century. 4. Fagus has always been an important component of the forest vegetation of the Beles Mountains. It demonstrates a short-term expansion between the end of the 17th until the mid-19th century, recorded also for the beech forests in other mountains of Northern Greece. REFERENCES Athanasiadis N (1975) Zur postglazialen Vegetationsentwicklung von Litochoro Katerinis und Pertuli Trikalon (Griechenland). Flora 164: 99-132. Athanasiadis N, Gerasimidis A (1986) Zur postglazialen Vegetationsentwicklung des Voras - Gebirges (Almopia – Griechenland). Wiss Jahrb Fak Forstwiss nat Umwelt Univ Thessaloniki 29 (4): 211-249 (In Greek with German summary). Athanasiadis N, Gerasimidis A (1987) Zur postglazialen Vegetationsentwicklung des Paikon - Gebirges (Nord Griechenland). Wiss Jahrb Fak Forstwiss nat Umwelt Univ Thessaloniki 30 (11): 403-405 (In Greek with German summary). Athanasiadis N, Gerasimidis A, Eleftheriadou E, Theodoropoulos K (1993) Zur postglazialen Vegetationsentwicklung des Rhodopi-Gebirges (Elatia Dramas - Griechenland). Diss Bot 196: 427-437. Athanasiadis N, Tonkov S, Atanassova J, Bozilova E (2000) Palynolological study of Holocene sediments from Lake Doirani in northern Greece. J Paleolimn 24: 331-342. Bottema S (1979) Pollen analytical investigations in Thessaly (Greece). Palaeohistoria 21: 19-40. Bozilova E, Tonkov S, Popova T (1995) Forest clearance, land use and human occupation during the Roman colonization in Bulgaria. Palaeoclimate Research 10: 37-44. Faegri K, Iversen J (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester. Flocas A (1990) Compendium of Meteorology and Climatology. Thessaloniki, 468 pp. Gerasimidis A (1985) Standortkundliche Verhältnisse und postglaziale Vegetations-entwicklung der Wälter Lailias, Bez. Serres und Katafygi im Pieria-Gebirge (Nordgriechenland). Wiss Jahrb Fak Forstwiss nat Umwelt Univ Thessaloniki 26 (7): 1-133 (In Greek with German summary). Gerasimidis A (1995) Anthropogenic influence on the development of forest vegetation in Greece. Evidence from pollen diagrams. Scientific Annals of the Department of Forestry and Natural Environment Thessaloniki 38/1: 170-203 (in Greek with English summary). Gerasimidis A, Athanasiadis N (1995) Woodland history of northern Greece from the mid Holocene to recent time based on evidence from peat pollen profiles. Veget Hist Archaeobot 4: 109-116. Grimm E (1991) Tilia and Tilia-graph. Illinois State Museum, Springfield, USA.

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H.A.G.S. (1969) Hellenic Army Geological Service, maps of Kastanoussa, Poroia and N. Petritsion, scale 1:50.000, Athens. I.G.M.E. (1983) Geological map of Greece, scale 1:50.000, Athens. Mattfeld J (1927) Aus Wald und Macchie in Griechenland. Mitt Deutsch Dendrol Gess 38: 106-151. Mavrommatis G (1980) Le bioclimat de la Gréce. Relations entre le climat et la végétation naturelle. Cartes bioclimatiques. Inst de Recherc For d’ Athénes, 66 pp+cartes. Mountrakis D (1985) Geology of Greece. Thessaloniki (In Greek). Panovska H, Bozilova E, Tonkov S (1990) Late Holocene vegetation history in the western part of Belasitsa mountain. In: 2nd Hellenic-Bulgarian Symposium, Aristotle Univ Press, Geographica Rhodopica 2: 1-7. Regel C (1937) Uber die Grenze zwischen Mittelmeergebiet und Mitelleuropa in Griechenland. Ber Deutsch Bot Ges 55: 82-91. Stojanoff N (1921) Floristische Materialen von dem Belasitza-Gebirge. Ann Sofia Univ: 1-134. Stuiver M, Becker B (1993) High-precision calibration of the radiocarbon time scale, AD 1950 6000 BC. Radiocarbon 35: 35-65. Willis KJ (1992) The late Quaternary vegetational history of northwest Greece. II. Rezina Marsh. New Phytol 121: 119-138.

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© The PENSOFT Publishers Late-Holocene Sofia - Moscow

Spassimir Tonkov (ed.) 2003 vegetation history of Gavdos (Crete) in relation toAspects long-distance ... Palaeoecology 199 of Palynology and Festschrift in honour of Elissaveta Bozilova, pp. 199-212

The Late-Holocene vegetation history of Gavdos (Crete) in relation to long-distance pollen dispersal: the Trypiti pollen diagram Sytze Bottema1, Katerina Kopaka2 and Apostolos Alexopoulos3 1

Groningen Institute of Archaeology, Poststraat 6, 9712 ER Groningen, The Netherlands E-mail: [email protected] 2 University of Crete, Department of History and Archaeology, Gallos University Camp, Gr-74100 Rethimno, Crete, Greece 3 University of Athens, Department of Geology, Zografou University Camp, Gr-15787 Athens, Greece

ABSTRACT The southernmost point of Europe, the little Greek island of Gavdos, south of Crete, has a pronounced Mediterranean climate. The present vegetation results from the edaphic factors, as well as human occupation since the Late Neolithic. This vegetation is characterized by two juniper species, lentisc and, quite recently, turpentine pine. The climate excludes central European deciduous trees. In a pollen core from the lagoon of Trypiti, dated three millennia back, several representatives of the birch and oak family are found which must be attributed to long-distance transport. This evidence sheds new light upon the pollen record of Crete where the low percentages of such species have been explained as scarce occurrences in the island. The near absence of pine in Gavdos as deduced from low pollen values found for the last three thousand years contrast with the modern situation in which turpentine pine is abundant. At the same time pine has increased in the adjacent part of Crete. The recent increase in pine trees and/or in pine pollen in the Eastern Mediterranean is remarkable. KEY WORDS: Vegetation history – Pollen – Gavdos – Greece – Long-distance transport – Pine

INTRODUCTION The little island of Gavdos, and particularly the Trypiti bay area (Fig. 1), constitutes the southernmost boundary of Greece and Europe, towards Africa. The local vegetation development is of interest since this island carries exclusively Eu-Mediterranean vegetation. Any long-distance transport of pollen from the European mainland must be clearly visible

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Fig. 1. Map of the island Gavdos. Black stars indicate the core locations.

in the local pollen precipitation. Furthermore, changes in vegetation composition were investigated in relation to the impact of prehistoric man. Work on Gavdos has been undertaken since the 1990s and includes a systematic surface survey, conducted by the Department of History and Archaeology of the University of Crete, the Ephoreia of Prehistoric and Classical Antiquities at Chania, and a multidisciplinary investigation coordinated by this Department, more specifically directed towards the coevaluation of the environmental and cultural wealth of the island. Emphasis was put on studying the interaction and interconnection of ecosystems and the extent to which these have been disturbed. The palynological investigation, realised by the Groningen Institute of Archaeology, falls into the latter approach and aims to clarify some aspects of this particular paleo-ecological perspective. GEOGRAPHY AND CLIMATE Gavdos is one of the largest and most remote satellite islands surrounding Crete and the only one that has been inhabited constantly for a long period. It forms a micro-insular complex with the islet of Gavdopoula, lying in the Libyan Sea, off the southwestern Cretan shore (standard parallels 25°05’E and 34°50’N). With a length of 10 km and a width of 5

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km, the total surface of Gavdos is almost 33 km2. The island displays a quite irregular relief, its highest point lies 368 m above sea level. Dramatically depopulated mainly since the Second World War, the island nowadays has a very restricted population, ranging from ca. 100 (official number) to 30-40 permanent inhabitants in wintertime. A pronounced Mediterranean climate prevails with a marked, dry 6-to-8-month summer (Bergmeier et al. 1997). Winter temperature is hardly ever below zero. Mean annual precipitation is less than 400 mm. During the summer, north and northwesterly winds prevail, whereas winds blow from the south during springtime (red dust, brought in by a Saharan sandstorm and sampled in April 2001 in Chania (Crete) by Dr. A. Sarpaki, contained olive pollen, but no typically African pollen types). GEOLOGY In Gavdos only two of the many geo-tectonic units of Greece occur, the Olonos-Pindos unit and the Calypso unit. There are also Neogene and Quaternary sediments (Alexopoulos 1999). The Neogene sediments cover two thirds of the island and comprise conglomerates, sands, marls, sandstones and bioclastic-biogenetic marly limestones. Quaternary sediments appear scattered all over the island. They comprise: 1) thin marly limestones of Pleistocene age; 2) calcareous sandstones most probably of Tyrrhenian age; 3) cross-bedded aeolianites with a lot of representatives of the terrestrial snail Helix cincta (15000 to 7000 years old (Welter-Schultes 1995, 1998)); 4) sands and recent sand-dunes; 5) sea terraces consisting of thousands of marine organisms (vermetites, serpoulas, etc.) strongly cemented with sand grains. Locally there are pieces of pottery within this formation. The formation occurs mainly on the Lavraca coast and indicates recent shoreline movements (upward or downward). Some of these (upward movements) took place during the last two to three thousand years. Recent deposits (alluvial, talus cones, scree, fluvial deposits, etc.) occur in low-lying areas and at the bases of steep slopes. Although the geological structure of Gavdos is simple, its evolution is very complex since Gavdos is located at the front of the subduction of the African plate below the Eurasian one (Fig. 1). As a result, complicated, diachronic, tectonic processes have folded, thrust, overthrust and faulted the Pindos Unit formations and have caused the metamorphism and the overthrusting of the Calypso unit on the Pindos unit, and the discordant deposition of Neogene sediments over the previous mentioned geo-tectonic units. These units are responsible for the successive vertical movements (upward and downward) and have shaped the actual form of the island. In the Trypiti area, following the Neogene period, a longitudinal morphological basin facing the sea was formed, due to the combined action of tectonics and erosion. In the past, part of this graben has periodically acted as a small lake or lagoon. The present name of this depression is Alyki (salt marsh). It is up to 200 m wide and at least 450 m long, its lowest altitude 0.60 m above sea level. Towards the sea is a natural embankment, 1.5 m

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high, consisting of sand, shingle, mud and clay. From time to time seawater washed over this natural barrier and the area was transformed from a marsh or lake into to a lagoon. The periodical contact of this area with the sea explains the successive layers of gypsum found at different depths in a core collected for palynological investigations. On the margins of the graben, sediments of the Pindos Unit have developed, mainly consisting of intercalations of thin-bedded limestones, pelites, and cherts of Maastrichtian age. At various locations small outcrops of the Neogene can be detected, comprising calcareous-marly breccia and intercalations of white-yellow marl and sandstone (Fig. 2). At the eastern margin of the graben and at a distance of two metres from the shore, a remnant of a marine terrace has developed into an aeolianite that contains the terrestrial fossils of Helix cincta. The presence of aeolianites suggests that the configuration of the graben must have occurred at least 7000 years ago, the youngest date of Helix cincta according to Welter-Schultes (1995, 1998). The periodical contact of the graben with the sea is either due to the destruction of the embankment by the erosional action of large waves, formed when intense south-southeast winds dominate, or due to the shifting of the present sea level caused by the uplift or subsidence of the island through tectonic movements (e.g. seismic activity), or to both.

Fig. 2. Geological map of the Trypiti bay area. A black triangle indicates the core location. 1: Alluvial deposits, 2: Coastal deposits (sands, gravels), 3: Aeolianites, 4: Fluviatile, lacustrive, lagoonal, or marine sediments, 5: Neogene deposits, 6: Formations of Pindos Unit, 7: Location of core sampling, 8: Fault.

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HISTORICAL SOURCES Historical and archaeological evidence concerning human presence on Gavdos is provided by earlier field work (Levi 1927; Colini 1925-26), as well as by a recent systematic survey (Kopaka 2001, 2002). It suggests a relatively early colonisation of the island in the Final Neolithic, in the 4th millenium, then a diachronic occupation through the Bronze Age, and Greek, Roman and later antiquity to modern times. Moreover, the island has always been on maritime crossroads, especially in times when commercial and other maritime activity used the southern Mediterranean sea-routes and passages (Kopaka and Gondica, forthcoming). Mostly because of to its geographical position on important Mediterranean maritime routes, Gavdos was mentioned by ancient authors, such as Herodotus, Strabo, Pliny, Ptolemy, and by medieval and later travellers, for instance Buondelmonti, Basilicata, Raulin, Pococke, and Pouqueville (Kopaka 2002). It is worth noting that, according to Callimachus, the name Gavdos is related to Homeric Ωγυγια, the island of Calypso. Throughout its habitation history, the island seems to follow, in different levels and degrees, the main Cretan cultural sequences, although constantly presenting well-defined local particularities regarding its material culture. Densely scattered Minoan pottery seems to represent all levels of this third-and second-millennium civilisation, with an emphasis on the Early- and Middle-Minoan periods (Kopaka and Papadaki, forthcoming). Moreover, architectural features and movable finds demonstrate an exploitation of the inland, as well as the coastal zones, throughout historical times. Human presence seems to have been intensive in the Hellenistic, Roman and above all in the Late Roman-Protobyzantine periods (Kossyva et al., forthcoming). Of particular interest are also the 19th and early 20thcentury remains on Gavdos (e.g. Nikolakakis, forthcoming). Some aspects of human interaction with the natural and cultivated environment are documented by both ancient and recent written sources and archaeological surface finds most of which could be ultimately traced back to prehistoric times (Kopaka 2002). The written sources mainly relate to the exploitation of juniper wood and fruit, to cereal cultivation (also attested by the numerous old terraces (pezoules)), important wine production, indicated by dozens of ancient carved rock winepresses all over the island (Christodoulakos et al. 2001), and perhaps to a lesser degree, olive-oil production (Drossinou, forthcoming). Nowadays, pine trees, rapidly tend to occupy the deserted terraces. Rare vines, no longer productive, as well as some figs and carobs can still be found. Olive trees have been planted recently. Older trees, like those present in the central part of the island, and in the yard of the University of Crete field station, would produce small fruit and had to be watered regularly. The few modern olive groves in Ampelos and in wind-protected parts of the Sarakiniko valley are also irrigated. They produce modest quantities of good quality olive oil, tasted by the second author in 2002, thanks to a gift by Gerty and Manolis Vaïlakakis. The Trypiti region displays many of the above natural and man-made features, pointing to early (Neolithic) human presence and further occupation during the subsequent prehistoric

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and historical times, especially Roman and Byzantine. Moreover, to its economic resources must be added the production of sea-salt in the coastal lagoon of Alyki. MODERN VEGETATION The modern flora of Gavdos is discussed by Bergmeier et al. (1997), who give a floristic inventory, with brief remarks on the vegetation. Their study is of great value for comparison with the subfossil pollen record. Gavdos carries a pronounced but poor Mediterranean vegetation with a limited ground cover mainly restricted by low rainfall. The island has no perennial streams and only a few small spots in the stream valleys remain moist without even showing water. The vegetation cover varies from barren to about 30%. In the southern part, some stretches of upland are completely devoid of vegetation. Where dry stream valleys cut into the land, the vegetation cover may reach about 30% because of the presence of pine trees. The junipers are mostly not more than four metres high and the pine trees seldom reach more than six metres. The pine trees are younger than the junipers, suggesting a transitional phase in the succession. Bergmeier et al. (1997) report two-metre-high scrub of Pinus brutia, suggesting that the increase in pines was still taking place in the 1990s. A recent increase in Pinus brutia is mentioned for southwestern and southeastern Crete by Rackham and Moody (1996: p. 62). According to Bergmeier (1999) various authors emphasize the absence or scarcity of trees until 1945 and less than 10% of the island was wooded around that time. Nowadays extensive areas are covered by rather dense pine woodland. Cultivated, often terraced land once occupied 40% of the island, but is now reduced to 4-5%. The abandoned land was rapidly conquered by pine mainly after 1950. Pinus brutia, Juniperus macrocarpa (oxycedrus ssp. macrocarpa) and, to a large extent Juniperus phoenicea, define the arboreal aspect. Especially common is the juniper called Kedros, which is the name for Juniperus (oxycedrus) macrocarpa, not to be mistaken for Cedrus, which does not occur in the island. The coastal area shows large patches of lentisc (Pistacia lentiscus). Goats avoid this species. A few plane trees (Platanus) are present in the Panaghia gorge. Olive (Olea) occurs rarely in the island and survives only when regularly watered. Apart from terracing and other cultivation activities, the apparently continuous goatkeeping must have greatly influenced the local vegetation. The total number of goats in the island in various periods is not known to the authors, but shipping of hay to the island was observed in October 1998, suggesting a low local carrying capacity. PALYNOLOGICAL INVESTIGATION, FIELD WORK AND METHODS Sampling To investigate the vegetation history of Gavdos, cores for palynological analysis were collected by means of a Dachnowski sampler at three locations. From the section on Geology

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it can be learned that soft and moist alluvial deposits suitable for pollen analysis are extremely rare in the island. A first coring was made near Saint George (Aghios Georgios), in the lower Kedrès stream valley, near Spaniolakkas. The local vegetation consists of Nerium oleander and Samolus valerandi. The valley itself lies in the Juniperus macrocarpa open forest of Kedrès (Kedros = juniper), one of the most important juniper vegetations in Greece. In this vegetation also Pinus brutia and Pistacia lentiscus are found. This coring was made in a place (1.5 m wide and 3 m long) where the water was held by blocking of a tiny source to provide drinking water for goats. About 1.4 m of yellow clay was cored which sometimes contained a little gravel. Underneath the yellow clay, dry, lime-rich clay was hit that made further coring impossible. A second coring was made in the neighbourhood of Saint Paul (Aghios Pavlos), near a well at the foot of a sandstone rock. About 1 m of yellow clay with sand layers was sampled. Then running sand filled the core-hole and made further sampling impossible. Judging by the anthropogenic character of both coring sites, features created to provide a little drinking water for goats, both cores might be very young. A third core was collected in the lagoon of Trypiti. For a detailed description of the area, see Geology. The bottom of the lagoon is covered with red algae, which have dried up. On the edge of the lagoon, low grass (cf. Puccinellia) grows and several specimens of Statice were seen on the sandy terrace just inside the beach barrier that separates the lagoon from the sea. Higher up, bordering the lagoon, Juniperus macrocarpa, Juniperus phoenicea, Pistacia lentiscus and Thymus are present. On the plateau above the lagoon, the ruins of a sheepfold were lying in a barren landscape. In the sparse vegetation, patches of Pistacia lentiscus were found, while locally Plantago lagopus was very common. The vegetation cover in the southern part of the Trypiti area is considerably lower than in the north. Precipitation evidently was sufficient for cereal production, because agriculture was practised here, as shown by the abandoned terraces. The centre of the lagoon was cored, which resulted in 3.8 m of soft, yellow-ochre to grey clay, parts of which contained layers of gypsum crystals (2.20, 2.38 m; around 3.30 m and at the bottommost level of 3.80 m). The coring was forced to stop, because the corehole constantly filled upwith gypsum crystals. Organic matter, including pollen, was found to be completely oxidised in the yellow clay. Well-preserved pollen was present only in the four layers of gypsum crystals (calcium-carbonate), several centimetres thick. From these deposits, pollen spectra could be produced. Absolute dating Two levels of the Trypiti core were AMS dated at the Centre for Isotope Research in Groningen: GrA-18898 GrA-18880

Trypiti 345-355 cm Trypiti 356-370 cm

2560±60 BP 13δ -0,32‰ (seawater corrected): 2770±60 BP 13δ -2,9‰:

829-413 cal. BC (2σ) 1049-805 cal. BC (2σ)

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The values of 13δ inform us about the local moisture conditions, which must have been terrestrial at 370 cm and turned marine in the following 20 cm. Assuming a constant sedimentation rate, the pollen evidence covers 1680-2900 uncalibrated radiocarbon years. In calendar years this would be about 1259–935 cal. BC to AD 241–531 corresponding with the Late Minoan, Roman and early Byzantine periods. DISCUSSION OF THE TRYPITI POLLEN DIAGRAM The diagram (Fig. 3) is based upon the subfossil evidence from the core in the Trypiti lagoon, from a depth of 220-380 cm. Subfossil pollen is found in the gypsum layers from 220 cm downward to 380 cm. The diagram is based upon a pollen sum including all pollen types found, apart from Plantago lanceolata/lagopus, because Plantago lagopus was present in large numbers around the surface-sample site. Types in the subfossil spectra of Trypiti were identified with a light microscope under 400-1000 x magnification and with the help of an extensive reference collection. Nomenclature is mainly according to the standards of the European Pollen Database in Arles. The so-called “main” diagram, which is drawn in the pollen diagram between the arboreal pollen and the herbs, shows the relation of the arboreal (tree) pollen to the non-arboreal (herb) pollen. There is a fundamental difference between modern terrestrial samples and sediment samples collected from a lake or marsh. The problem of long-distance transport The first part of the diagram shows a series of pollen curves produced by tree species, which do not occur on Gavdos. This group includes several pollen types which are identified up to the species; others are identified to the level of a genus represented by a very limited number of species: Alnus, Betula, Corylus, Carpinus betulus, Ostrya carpinifolia/Carpinus orientalis, Quercus coccifera-type, Quercus-deciduous-type, Fagus, Phillyrea, Punica and Humulus/Cannabis. Whether pollen is proof of the presence of a species in a certain situation, is a question that is very difficult to answer. For a reconstruction of the vegetation history of Crete this problem plays an important part in the interpretation of the finds of these pollen types. The explanation of the presence of the central-European tree pollen on a Mediterranean island like Gavdos is very instructive. One could postulate that when a tree species becomes extinct in a remote place like Gavdos or Crete, the pollen production declines and decreases towards zero when the tree or herb species has disappeared and no supply from elsewhere occurs. When the tree pollen type concerned is, however, continuously present up to modern times, as is the case in diagrams from Crete (Bottema and Sarpaki, forthcoming) although the tree species itself is absent, one has to consider a pollen source somewhere else. The pollen finds in Trypiti (Fig. 3) of the first thirteen types are generally from the European

Fig. 3. Pollen diagram of Trypiti with the modern sample of nearby upland.

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continent or possibly from Crete, it is out of the question that these trees ever grew on Gavdos. It is likely that pollen of Quercus coccifera-type, deciduous oak and olive pollen mainly come from the nearest source on Crete. Trypiti and Gavdos clearly demonstrate that catchment basins that receive certain pollen types are not necessarily the place where one can postulate the presence of such species. The evidence from Gavdos can be used for the island of Crete to study the implications of long-distance transport in the case of certain tree types that have continuous pollen curves but are not found in the island. Representation of pollen types If we translate the 457 plant species from 73 families reported by Bergmeier et al. into pollen types, the number for Gavdos would be reduced to 84 pollen types. This number of course depends upon the possibilities of light microscopy, the skill of the analyst and the available reference material. The reduction is mainly caused by the number of herb species, which share the same pollen type. For instance, all grasses (Gramineae) share one pollen type. In the subfossil spectra of Trypiti, 65 pollen types were identified, but they only partly cover Bergmeier’s list (Bergmeier et al. 1997). Fifteen pollen types represent taxa that are not recovered from the island and are indicative of long-distance dispersal. We can eliminate this group of fifteen taxa (twelve trees, one of a liana and two herbs) which do not occur on Gavdos and, because of the islands’ geographical and climatic position, cannot have grown there. In the herb-pollen category, the identification level is lower than in the tree-pollen group, because the trees are often represented by single species, guaranteeing easy identification. Herb-pollen types found on Gavdos mostly have a potential producer in the island, with a few exceptions: some pollen of Ephedra fragilis-type and Datisca was found but no producers are mentioned for the island. The rather extreme saline conditions in the Trypiti basin allow only a few salt-tolerant species to survive locally, but a reasonable number of 50 pollen types represents the general Gavdos-island vegetation. Included in Bergmeier’s list are some neophytes (imports), which were not present at the time of the subfossil-pollen spectra in the diagram. Some of the plant species mentioned for Gavdos can be excluded, because under normal conditions their pollen would never be found. For instance, Ficus is left out, because its pollen is not released to precipitate freely, but fertilisation takes place inside the fruit. Some pollen types, such as Juncus species or Nerium oleander, are so fragile that they are hardly ever found in a subfossil state. Late Holocene vegetation history The vegetation reconstruction is based upon the pollen evidence for the period of 1000 BC to AD 400, as indicated by the two AMS dates discussed before.

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In the spectra of the diagram (Fig. 3) several pollen types occur that seem to be indicative of the kind of vegetation found in the island at that period. On the slopes around the lagoon of Trypiti the most abundant shrub was Pistacia lentiscus. The lentisc is one of several pistachio species, which never have large shares in the pollen rain and tend to be quite under-represented (Bottema and Barkoudah 1979). The 20-40% that lentisc scores in Gavdos demonstrate that it must have dominated the vegetation locally. Junipers formed part of the open forest on the slopes and especially on the upland plateau. Nowadays Juniperus macrocarpa and Juniperus phoenicea are recorded for Gavdos; they share the same pollen type. For that reason is it impossible to trace their specific histories on the basis of pollen. Olives may have occurred in Gavdos, but only when taken into cultivation. In Roman times, the olive-pollen value increased from about 2% to 12% but it is far from certain that this reflects an increase in olive trees. Roman irrigation methods are known to be advanced; and on Gavdos itself archaeological evidence includes a well-made Roman drainage and irrigation system within Kedrès, consisting of an aqueduct, basins and channels. Moreover, olive pressing installations and other related finds of the same period point to an intensified presence of olives - although part of the attested pollen may still originate from Crete. It is significant that this Mediterranean species cannot survive on Gavdos without additional water, because this indicates that there definitely was not enough precipitation for the deciduous tree species of which pollen is found. Pine, now an important species on the island, was from 1000 BC until AD 400 (the period covered by the pollen evidence) present with 2-4% pollen only. Such pine-pollen percentages indicate absence of the producer and must be attributed to long-distance transport. Pine even reaches more than 30% in the modern sample from above the Trypiti lagoon, demonstrating that since about AD 400 there has been a moment when this species increased considerably in the island. This event took place very late and was observed in the twentieth century (Bergmeier 1999). The behaviour of pine pollen in the Eastern Mediterranean during recent centuries is not very well understood. In many places, pine pollen has high values during the youngest half of the Holocene and in such areas often large stretches of pine forest, represented for instance by Pinus nigra or Pinus brutia, are found. In many places the upper part of the sediment has lost its pollen owing to drainage, so the more recent part of the pine-pollen curve is not present. What we do have is the modern pine-pollen production in the form of percentages in modern samples. These values are often very high, even when locally no pine is observed. It was thought that pines perhaps occurred in hilly or mountainous landscapes at a certain distance from the road system, an idea supported also by employees of the Turkish State Forestry. It has also been suggested that the local pollen production of herbs had been reduced by overgrazing to such an extent that pine, which is a renowned pollen producer and distributor, became very much over-represented. An example of such long-distance dispersal is a modern sample from the Bouara salt-flats on the Syrian-Iraqi border. Here pine trees occur at a distance of 400 km, but nevertheless the value in the

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pollen precipitation is 12%. This value is caused especially by the near-absence of local pollen (Gremmen and Bottema 1991). Developments of Pinus pollen as described have been demonstrated in western Turkey for the Yenișehir area (Bottema et al. 2001). For northern Turkey the complex behaviour of pine pollen was already pointed out in Bottema et al. (1993/1994: p. 33) (see also Beug 1967). One might think that a large amount of pine pollen is present throughout the Eastern Mediterranean while the local vegetation is not very productive, because of overgrazing or because of steppe conditions. This is, however, not always the case because there are examples of modern pollen precipitation in which pine pollen plays no role. In northern Israel, the increase in pine pollen is very well visible in the upper part of the diagram of Kinneret (Baruch 1983). These high values seem to correlate with the extensive Aleppo pine forest on Mount Carmel. One could postulate that such an increase of Pinus halepensis is the result of anthropogenic activity, especially frequent burning, which results in quick regeneration and subsequent expansion. The recent explosion of Pinus brutia on Gavdos can hardly be explained by sudden human intervention, because the island had witnessed habitation for millennia already. Instead, the cause seems to have been a certain lessening of pressure, or even abandonment of farmland. Frequent fire, as on Mount Carmel, cannot have been the cause in Gavdos because it would have destroyed more of the juniper vegetation. For the period of 1000 BC to AD 400, the situation was not favourable for Pinus brutia and the course of the curves of Juniperus, Pistacia, Olea and Cistus in Figure 3 points to quite stable conditions with an emphasis on olive culture, possibly also from Crete, during Roman times. The production of Punica may have played a role during the later Roman period. The archaeological evidence points to fairly intensive occupation from the late Neolithic onward (see Historical sources), but unfortunately no pollen evidence is available from this period. The pollen record starts about 1000 BC with the Iron Age, which may have witnessed the vegetation changed already by preceding cultures. Human activity continued and during the following one and a half thousand years (spectra 1-5, 220-370 cm) an increase in anthropogenic pressure took place, as indicated by the increase of Ericaceae pollen from 2 to 5% and from about 1 to 10 % for the prickly Poterium spinosum. Both pollen types are produced by plant species indicative of the degradation of Mediterranean vegetation. 1600 years later, the modern pollen rain recorded for the Gavdos plateau has much in common with the past spectra, apart from the striking increase of pine. Differences occur between the modern sample and the subfossil spectra from the lagoon, for instance in the values of Liguliflorae, Plantago lagopus and Galium. But these probably reflect differences in sampling method rather than differences in vegetation. ACKNOWLEDGEMENTS Thanks are due to the University of Crete, for the hospitality in the University fieldwork station at Siopata. We also thank Reinder Reinders, Professor at the Groningen Institute of

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Archaeology for his unfailing energy and help in the coring expedition on Gavdos. Gertie Entjes kindly prepared the manuscript. Drawings were made by Hans Zwier. The English was corrected by Xandra Bardet. REFERENCES Alexopoulos A (1999) The geological, hydrogeological and water supply conditions of Gavdos island, today’s situation and perspectives. Proceedings of the 5th Pan Hellenic Geographic Congress of the Geographic Society of Greece, Athens: 38-48. Baruch U (1983) The Palynology of a Late Holocene Core from Lake Kinneret. Department of Prehistory, The Hebrew University, 33 p. Bergmeier E (1999) Gavdos - Europe’s southernmost island between stability and change. Geoökodynamik 20, 1/2: 87-97. Bergmeier E, Jahn R, Jagel A (1997) Flora and vegetation of Gavdos (Greece), the southernmost European island. 1. Vascular flora and chorological relations. Candollea 52: 306-358. Bottema S, Barkoudah Y (1979) Modern pollen precipitation in Syria and Lebanon and its relation to vegetation. Pollen et Spores 21: 427-480. Bottema S, Sarpaki A (forthcoming) Environmental change in Crete: a 9000-year record of Holocene vegetation history and the effect of the Santorini eruption. Bottema S, Woldring H, Aytu˘g, B (1993/1994) Late Quaternary Vegetation History of Northern Turkey. Palaeohistoria 35/36: 13-72. Bottema S, Woldring H, Kayan, I (2001) The Late Quaternary Vegetation History of Western Turkey. In: Roodenberg JJ, Thissen LC (eds) The Illplnar Excavations. NINO, Leiden, pp 327-354. Beug HJ (1967) Contributions to the postglacial vegetational history of northern Turkey. In: Cushing EJ, Wright Jr HE (eds) Quaternary Paleoecology. Yale Univ Press, pp 349-356. Christodoulakos I, Moshovi G, Kopaka K, Drossinou P (2001) Rock-cut wine-presses on Gavdos. 8th International Cretological Congress, Iraklio, pp 557-580 (in Greek). Colini A (1925-26) Esplorazione dell’isola di Gaudos. Bolletino d’Arte 55: 423-24. Drossinou P (forthcoming) Roman olive-press installations at Gavdos, Crete. Romano e Probizantina International Congres of the Italian Archaeological School of Athens, Iraklio (in Greek). ˘ ~ira. Gremmen WHE, Bottema S (1991) Palynological Investigations. In: Kühne H (Hrsg) The Syrian Gaz Die Rezente Umwelt von Tall S˘ eh Hamad und Daten zur Umweltrekonstruktion der Assyrischen Stadt Dkr-Katlimmu. Dietrich Reimer Verlag, Berlin, pp 105-117. Kopaka K (2001) Surface survey at Gavdos. Approaches of an insular microcosme on the fringe. 8th International Cretological Congress, Iraklio: 63-74 (in Greek). Kopaka K (2002) From the life of a prehistoric word. Ka-u-da and the products of the soil of Gavdos. SEMA in honor of Menelaos Parlamas (in Greek). Kopaka K, Drossinou P, Christodoulakos I (1996) Archaeological survey at Gavdos. Kritiki Estia 5 (1994/96): 242-244 (in Greek).

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Kopaka K, Papadaki Chr (forthcoming) Prehistoric pottery from the surface survey at Gavdos. The case study of a microinsular industrial production. 9th International Cretological Congress, Aghios Nikolaos (in Greek). Kopaka K, Gondica D (forthcoming) Cartographic recognition of the island of Gavdos. Travels into a microinsular geopolitical landscape. 9th International Cretological Congress, Aghios Nikolaos (in Greek). Kossyva A, Moshovi G, Yangaki A (forthcoming) Surface survey at Gavdos. Indications on the Roman and Protobyzantine occupation of the island. Creta Romana e Protobyzantina International Congress of the Italian Archaeological School in Athens, Iraklio (in Greek). Levi D (1927) The southernmost bound of Europe (Gavdos, the island of Saint Paul’s shipwreck). Art and Archaeol 24: 176-183. Nikolakakis G (forthcoming) The farmsteads of Gavdos. 9th International Cretological Congress, Aghios Nikolaos (in Greek). Rackham O, Moody J (1996) The making of the Cretan Landscape. Manchester Univ Press, Manchester. Welter-Schultes WF (1995) La végétation de l’île de Gavdos (Grèce), la plus méridionale de l’Europe. Influence de facteurs historiques et humains. Bilogia Gallo-Hellenica 21(2): 189-202. Welter-Schultes WF (1998) Die Landschnecken der griechischen Insel Gávdos, der südlichsten Insel Europas. Schr Malakozool 12: 1-120.

© PENSOFT Publishers vegetation Postglacial Sofia - Moscow

Spassimir Tonkov (ed.) 2003 dynamics in the coastal part of the Strandza Mountains ... Palaeoecology 213 Aspects of Palynology and Festschrift in honour of Elissaveta Bozilova, pp. 213-231

Postglacial vegetation dynamics in the coastal part of the Strandza Mountains, Southeastern Bulgaria Mariana Filipova – Marinova Museum of Natural History, 41 Maria Louisa bd., 9000 Varna, Bulgaria E-mail: [email protected]

ABSTRACT Pollen analysis was conducted on a core recovered from the flooded terrace near the estuary of the Veleka river in Southeastern Bulgaria. The radiocarbon dates indicated that the sediments were accumulated during the last 10000 14C years. The pollen record provides information on the environmental changes in the coastal area adjacent to the Strandza Mountains. The pollen assemblages suggest that open deciduous forests were established in the study area at the beginning of the Holocene. Evidence is collected in support of the existence of lateglacial refugia for temperate tree taxa in the Strandza Mountains. The formation of the firth of the Veleka river started at the beginning of the Holocene. KEY WORDS: Postglacial – Pollen analysis – Vegetation history – Veleka river – Strandza Mountains – Southeastern Bulgaria

INTRODUCTION The evolution of the postglacial vegetation could be quite different due to the geographic position, the altitude of the investigated area and the position of refugia (Welten 1982). It was suggested by many authors that temperate tree taxa survived in the mountainous areas of the Balkans during the cold stages of the Quaternary (Lang 1970; Bottema 1974; Beug 1982; Huntley and Birks 1983; Bennett et al. 1991). In this aspect, the geographical position of the non-glaciated Strandza Mountains in Southeastern Bulgaria seems suitable for a refuge area in order to elucidate problems related to tree migrations along the Black Sea coast during the Holocene. The reconstruction of the palaeoecological environment in Southeastern Bulgaria is also of great interest because the vegetation in this area was shaped under the influence of the temperate-continental and submediterranean climates and the moderate effect of the Black Sea as well.

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The palynological data on the flora and vegetation history in Southeastern Bulgaria throughout the Holocene originate mainly from sites located in the Black Sea coastal area – Lake Arkutino, Ropotamo region (Bozilova and Beug 1992), Lake Burgass (Atanassova et al. 2002), the submerged praehistorical settlements Urdoviza (near Kiten) and the harbour of Sozopol (Filipova et al. 1993; Bozilova and Filipova–Marinova 1994; Filipova–Marinova and Bozilova 2002). In addition, palynological data from Black Sea marine sediments are also available (Filipova et al. 1989; Atanassova 1990; Bozilova et al. 1997). Hitherto, the Strandza Mountains has not been palynologically investigated because of the lack of peat bogs and lakes suitable for such studies. The present paper provides new information on the postglacial vegetation history and climatic changes in Southeastern Bulgaria retrieved from pollen analysis of sediments from the flooded terrace near the estuary of the Veleka river that is winding along the Strandza Mountains. THE STUDY AREA Geography, geology and climate The study area belongs to the coastal zone of the Strandza Mountains near to the border with Turkey (Fig. 1). The Strandza Mountains on bulgarian territory is not high (632 m a.s.l.) and has a hilly relief indented by numerous valleys (Mikhailov 1989). Geologically, this zone belongs to the eastern part of the Strandza anticline morphostructure, formed by Cenozoic volcanogenous materials. During the Holocene as a result

Fig. 1. Location of the investigated core C-149.

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of the marine transgressions the estuary of the Veleka river and the adjacent bay turned into a firth (Popov and Mishev 1974). The climate is submediterranean and this area is more frequently under the influence of the mediterranean cyclones during the cold period of the year whereas the cold influence from the north comes mainly from the sea and is partially moderate. The winters are mild and almost without snow. The mean January temperature ranges between 2o C and 3.2o C. The minimal temperature falls below 0oC on rare occasions. The summers are hot and dry. The mean July temperature is about 23oC. The mean diurnal temperature exceeds 10oC before the beginning of November. The climate is characterized by a winter-autumn precipitation maximum. The annual precipitation sums are high (800-1000 mm) (Sabev and Stanev 1963; Tishkov 1989). The Veleka river is the main river in that area and takes its source from several karst springs situated on the territory of Turkey. The length of the river is 147 km and the catchment area is 995 km2. Near its estuary the Veleka river reaches 150 m width and 8 m depth and forms a firth separated from the sea by a sand bar during most of the year. A considerable quantity of sea water infiltrates or passes directly into the firth and increases its salinity (Popov and Mishev 1974). Modern vegetation According to Bondev (1991) the study area belongs to the Black Sea floristic region, Strandza subregion, Euxinian province. The recent plant cover of the Strandza Mountains was studied by many authors ( Stefanov 1924; Jordanov 1939; Markova et al. 1982; Velchev et al. 1985). This area is one of the most interesting regions in Europe where Tertiary relict forests of Fagus orientalis and Quercus polycarpa are distributed with an undergrowth of evergreen shrubs of Colchidian type – Rhododendron ponticum, Laurocerasus officinalis, Daphne pontica and Ilex colchica, with the occurrence of Pyracantha coccinea and Vaccinium arctostaphyllos. The presence of Trachystemon orientalis, Epimedium pubigerum, Salvia forskahlei and Cyclamen coum is characteristic for the herb layer (Stojanov 1941). These forests occur mostly in gullies or on shady slopes. Oak forests of Quercus polycarpa, Quercus frainetto, Quercus cerris are prevalent on the ridges at higher elevation. They are mixed with Fraxinus ornus, Tilia tomentosa, Carpinus betulus, Sorbus torminalis, etc. Forests of Quercus hartwissiana also occur near the border but more rarely. The undergrowth is composed of many mediterranean southeuxinian and submediterranean species. The submediterranean shrubs and herb communities are restricted in their distribution along the marginal area and on the mountain ridges. The forests in Strandza Mountains are the only place in Bulgaria where the evergreen Calluna vulgaris and the relict species Mespilus germanica grow. The main southeuxinian species in the area except Fagus orientalis are also Rhododendron ponticum, Teucrium lamifolium, Epimedium pubigerum, Daphne pontica, Hypericum calycinum. They occur in Bulgaria only in the Strandza Mountains. Fraxinus oxycarpa, Symphytum tauricum, Cicer montbretii, Lathyrus aureus, Trachystemon orientalis, Salvia forskahlei and Scilla bithynica are

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also found. There is a great diversity of typical mediterranean species such as Pistacia terebinthus, Phyllirea latifolia, Periploca graeca, Cistus incanus, Trifolium ligustrum, Lens ervoides, Erica arborea. In addition to the above mentioned southeuxinian species, the Tertiary relicts in the area are Ilex colchica, Pyracantha coccinea, Celtis caucasica. Periodically over-flooded forests (named in Bulgaria “longoz forests”) composed of Fraxinus oxycarpa, Ulmus minor, Quercus pedunculiflora, Alnus glutinosa and rich in lianas like Hedera helix, Clematis vitalba, Vitis vinifera, Periploca graeca, Smilax excelsa occur along the rivers running into the Black Sea (Stojanov 1928; Penev 1984). A reed formation consisting mainly of Phragmites australis, Typha angustifolia, Typha latifolia, Scirpus lacustris, Scirpus maritimus, Schoenoplectus triqueter is also found. MATERIAL AND METHODS The core C-149 (45 m in length, September 1985) was taken from the southeastern coastal zone of the Strandza Mountains in the palaeovalley of the Veleka river near to its estuary (42º 04' N and 27 º58' E) (Fig. 1). The coring was done using a Russian drilling equipment. The core was stopped in a coarse sandy layer above the Neogen rock and the interval between 45-43.5 m appeared palynologically sterile. The stratigraphic details of the core are shown on Fig. 2.

Fig. 2. Lithology of core C-149.

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For the palynological investigation samples at every 1 m were taken. The sample preparation followed the standard procedure (Faegri and Iversen 1989) removing the mineral components with sodium pyrophosphate and hydrofluoric acid (Birks and Birks 1980). A pollen diagram from selected taxa is constructed based on a pollen sum (PS) of arboreal (AP) and non-arboreal (NAP) taxa (Fig. 3). Excluded from the PS are pollen of aquatics, spores of Bryophyta and Pteridophyta, dinoflagellates and acritarchs. Their representation is expressed as percentages of the PS as defined above. The pollen content was not rich and in most cases a PS of 250-300 was achieved. The dinoflagellate cysts and some acritarchs were also counted. The statistical processing of the data and their graphic presentation were done with Tilia and Tilia-graph software programs (Grimm 1991). Pollen taxa with low values or of less importance are not shown in the pollen diagram. A list of these taxa follows providing an idea of the total pollen presentation and how the pollen zones were delimited: AP: Picea, Abies, Cornus mas, Viburnum, Ligustrum, Rhamnus/Paliurus; NAP: Plantago maritima, Plantago major/Plantago media, Centaurea cyanus, Centaurea depressa-type, Thalictrum lucidum, Cirsiumtype, Sanguisorba minor, Scleranthus, Rubiaceae, Trifolium, Lathyrus, Caryophyllaceae, Knautia, Valeriana, Polygonum bistorta, Helianthemum, Hypericum, Euphorbia, Liliaceae, Iridaceae, Convolvulaceae, Scrophulariaceae, Polygala, Campanula; Aquatics and pteridophytes: Equisetum, Lythrum, Polygonum persicaria, Dryopteris, Thelypteris, Ophioglossum, Botrychium; Dinoflagellates: Spiniferites ramosus The Marine Influence Index (MII) was also calculated and graphically presented after Traverse (1978) (Fig. 4). MII =

Dinoflagellates + Acritarchs Dinoflagellates + Acritarchs + Total pollen sum

RESULTS Radiocarbon dating Four samples were submitted for radiocarbon dating in 14C and 3H-Laboratorium, Niedersäshsisches Landesamt für Bodenforschung, Hannover, Germany. The results are presented on Table 1. The calibration was done using the program Calib 3.05 (Stuiver and Reimer 1993). The radiocarbon dates indicate the age of the sediments and are used to Table 1. Results of radiocarbon measurements. Depth (cm) 500 2490 3130 4210

14

C Lab. No (Hv-)

Age BP

Age* (cal. BC)

19928 19926 19404 19927

3690±70 8355±75 8580±70 9945±160

2180 – 1955 7490 – 7300 – 9785 – 9035

4500

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s nu Pi

n lo

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y ox pl di

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s lu tu be s us nu pi yl ar or C C

Fig. 3. Simplified percentage pollen diagram of core C-149.

9945+/-160 B.P.

8580+/-70 B.P.

8355+/-75 B.P.

3690+/-70 B.P.

AP/NAP

Core-149

Simplified percentage pollen diagram of Core-149

Depth(cm)

U

us

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lm

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us s lia g nu Ti F a Al

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is or al si nt el us on e c i n r dr o ex or s a en s e s s s u r e d e ru ea a u u nu in in pe y r do hn pe c er pi r ula ni hill ho ap uni ric a ed it is um ax rax alix ar c e et r u F F S C A B J P R D J E H V H

218 Mariana Filipova – Marinova

Depth(cm)

4500

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2000

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Fig. 3. Continued.

9945+/-160 B.P.

8580+/-70 B.P.

8355+/-75 B.P.

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A

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Depth (cm)

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Fig. 4. Marine Influence Index curve.

make comparisons with other regional studues. The date 9945±160 BP (9785–9035 cal. BC) is the oldest one and marks the time when the formation of the palaeovalley began. Pollen diagram The pollen sequence is divided into five pollen assemblage zone (PAZ), synchronized with the biostratigraphical subdivison of the Holocene in Bulgaria (Bozilova 1982) (Fig. 2). PAZ V-1 (4350-4060 cm, 3 samples) (Pinus-Quercus-Betula-Corylus) AP dominates with 67%. Pollen of Pinus diploxylon-type is present with 21%. Quercus pollen reaches 17-23.3%, Corylus 8-16.4%, Alnus 4-8.2% and Ulmus 5.5%. Betula pollen attains a maximal value of 14.2%. The rest of arboreal taxa such as Tilia, Fagus, Carpinus betulus, Juniperus do not exceed 3-4%. Pollen grains of Fraxinus excelsior and Salix are also found. Herb pollen is mainly represented by Poaceae 17.2%, Artemisia 8.6-21%, Chenopodiaceae 8.5%. Lower values of Aster/Achillea-type, Taraxacum-type, Apiaceae, Fabaceae, Lamiaceae, Brassicaceae pollen are established. Among the taxa of local origin Typha angustifolia/ Sparganium-type is present with 2.4% and Polypodiaceae with 1%. Dinoflagellate cysts of Spiniferites cruciformis are found. PAZ V-2 (3780-2770 cm, 10 samples) (Quercus-Corylus-Ulmus) AP dominates with 64.2-83%. Quercus pollen prevails and reaches two maxima of 38.8% and 44%. The most characteristic feature is the rise of Corylus and Ulmus pollen curves up to 19.5% and 8.7%, respectively. Pinus diploxylon-type is established with 1025%, Alnus 4.0-8.7%, Tilia and Fagus with 3-5% each. Betula pollen decreases up to 1%. Pollen grains of Cornus mas, Taxus, Juglans, Rhamnus/Paliurus, Daphne, Hedera, Vitis, Humulus/ Cannabis appear. NAP is represented by Poaceae 10%, Chenopodiaceae 5%, Artemisia 4%, Aster/Achilleatype, Cichoriaceae, Apiaceae, Fabaceae and Lamiaceae. Pollen of anthropophytes as Plantago lanceolata, Polygonum aviculare, Urtica, Filipendula and Scleranthus is found. The aquatics and

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pteridophytes are represented by Typha angustifolia/Sparganium-type 3%, Cyperaceae 2.8%, Myriophyllum spicatum 1%, Potamogeton, Pediastrum. Single spores of Polypodium, Ophioglossum and Botrychium are found. An increase of the dinoflagellate cysts of Spiniferites cruciformis up to 5.8% is marked. Single cysts of Lingulodinium machaerophorum and acritarchs Cymatiosphaera globulosa occur. PAZ V-3 (2680-1700 cm, 9 samples) (Quercus-Tilia-Alnus) AP retains its dominant position with 80-85%. Quercus pollen prevails and a sharp maximum of 54% is recorded at level 1900 cm. In comparison to the previous zone lower values for Corylus 10%, Ulmus 5% and Pinus diploxylon-type 6% are established. Alnus curve increases up to 19% at the beginning of the zone and then decreases to 5%. Pollen of Tilia, Fagus and Fraxinus excelsior increases up to 9.7%, 4% and 2.2%, respectively. From this zone upwards starts the continuous presence of Carpinus arientalis and Acer. The first pollen grains of Fraxinus ornus also appear. Pollen of Salix, Taxus, Daphne, Juglans, Ericaceae, Abies, Picea, Hedera, Vitis and Humulus/Cannabis is determined. The variety of NAP taxa is great and among them the highest percentage values are recorded for Chenopodiaceae 4%, Poaceae 3%, Artemisia 2%. The constant presence of Cerealia-type, accompanied by Plantago lanceolata, Polygonum aviculare, Urtica, Carduus-type, Cirsium-type and Filipendula, begins in this zone. Pollen grains of Aster/Achillea-type, Cichoriaceae, Taraxacum-type, Plantago maritima, Cantaurea jacea-type, Sanguisorba minor, Rubiaceae, Apiaceae, Fabaceae, Lamiaceae, Ranunculaceae and Scrophulariaceae are found. The dominant local components are Typha angustifolia/Sparganium-type 6.2%, Cyperaceae 2.6% and Polypodiaceae 3.5%. Single pollen grains of Myriophyllum spicatum, Polygonum persicaria, Lemna and Botrychium occur. There is a change in the type of dinoflagellate cysts marked by an increase of Lingulodinium machaerophorum up to 4.2% and acritarchs Cymatiosphaera globulosa up to 12.3%. Only single cysts of Spiniferites cruciformis are found. PAZ V-4 (1480-610 cm, 7 samples) (Quercus-Carpinus betulus-Fagus) AP dominates with 75-84% but a change in the composition of the pollen spectra is established. The values of Corylus, Ulmus, Tilia and Pinus diploxylon-type decrease to 2.7%, 1.9%, 0.9% and 4%, respectively. The most characteristic feature is the increase of Carpinus betulus reaching 19.5% and Fagus 7.8%, simultaneously with a decrease in the pollen frequencies of Quercus to 30%. Pollen of Fraxinus excelsior 5.4% and Carpinus orientalis 6.2% is also found. Single pollen grains of Picea, Abies, Betula, Acer, Juglans, Rhamnus/Paliurus, Phillyrea, Ericaceae, Hedera and Vitis are determined. Pollen of Poaceae 6.6%, Chenopodiaceae 4.4%, Artemisia 3.6% and ster/Achillea-type 2.7% is prevailing. Single pollen grains of Cerealia-type and the anthropophytes Polygonum aviculare, Plantago lanceolata, Carduus-type, Cirsium-type, Urtica and Filipendula are found. Taxa of local origin such as Typha angustifolia/Sparganium-type, Cyperaceae and Ophioglossum are established. Maximal value of 15.7% is registered for the dinoflagellate cysts of Lingulodinium machaerophorum and for the acritarchs Cymatiosphaera globulosa up to 7.5%.

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PAZ V-5 (520-350 cm, 3 samples) (Quercus-Ulmus-Alnus-Salix-Fagus) AP dominates with 74-83.5%. In this zone Quercus retains its dominant position but decreases to 23.5%. A typical feature is the rise of Alnus with 20.8%, Salix 10.4%, Ulmus 8.5%, Fagus 8.1% and Fraxinus excelsior 5.1%. The rest of arboreal taxa as Pinus diploxylontype, Corylus, Tilia do not show any significant changes. Single pollen grains of Rhododendron, Cornus mas and Hedera are also established. The NAP taxa are quite diverse but with low frequencies. Among them Poaceae 5.8%, Aster/Achillea-type 5.1%, Chenopodiaceae 4% and Artemisia 2.3% deserve attention. A slight increase of the local components Typha angustifolia/Sparganium-type up to 5.6% and Cyperaceae up to 2.8% is observed. The dinoflagellate cysts of Lingulodinium machaerophorum decrease from 17.5% to 10% and the acritarchs Cymatiosphaera globulosa from 4% to 0.5%. DISCUSSION Vegetation history The pollen record from the Veleka river estuary reflects the vegetation history and palaeoenvironmental changes in the study area during the last 10000 14C years. The development of the vegetation in the Strandza Mountains is described on the basis of the characteristic features of the pollen zones distinguished. PAZ V-1 The base of the sequence could be assigned to Preboreal time confirmed by the radiocarbon date of 9945±160 BP. In this aspect, the new palaeoecological information is of great importance for the reconstruction of the vegetation cover in this area as data related to the onset of the Holocene are almost lacking in the marine sediments from the southern Bulgarian Black Sea shelf so far. The high values of AP testify that the improvement of the climate has favoured the establishment of an open forest cover. The presence of the pioneer species Betula in the area was the first sign of afforestation but this phase lasted only for several centuries. The subfossil evidence demonstrates that Betula was also more common in Northwestern Turkey during the Early Holocene than it is now (Bottema 1990). Soon after 9945±160 BP deciduous forests developed in the area with some birch probably growing in them. These forests were dominated by different Quercus species but other thermophilous trees such as Ulmus, Tilia, Corylus and Fraxinus excelsior were also present. According to Lang (1985) it is not sure if Quercus, Ulmus, Tilia, Fraxinus and Acer formed together real “mixed oak forests”. The distribution of these species depends on the edaphic conditions and topography. Most probably in the investigated area Quercus, Tilia, Ulmus and some Corylus had colonized the best soils on southern slopes, while Fagus and Carpinus betulus were distributed on northern slopes and in humid ravines. This first increase of deciduous tree pollen was dated also at

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9630±520 BP in core MC-544 from the deep part of the Western Black Sea (Filipova et al. 1989). In contrast to Central and Western Europe where Corylus was the first sciophilous species which migrated and dominated at the onset of the mesocratic phase, only to give way later to Quercus, Ulmus and Tilia (Birks 1986), in the Strandza Mountains as well as in other bulgarian mountains Corylus began to expand more or less simultaneously with Quercus, Ulmus and Tilia (Filipovitch 1981; Filipovitch et al. 1998; Bozilova 1995; Stefanova and Bozilova 1995; Stefanova 1998; Bozilova and Tonkov 2000; Filipovitch and Lazarova 2001; Tonkov et al. 2002). It is worth to mention the participation of Fagus in the pollen spectra since Preboreal time in contrast to pollen diagrams from other parts of the country. The debate is focused on Fagus orientalis, a species that was preserved during the last glaciation in some areas of Southeastern Bulgaria (Bozilova 1986; Filipova–Marinova 1995). A characteristic feature is the presence of single pollen grains of Rhododendron and Ericaceae. Therefore , we can conclude, that most probably these species were preserved in refugia in the Strandza Mountains during the Lateglacial. Salix is represented in the pollen spectra with low values but quite possible this tree had participated in the vegetation along the Veleka river and its estuary. It is well known from the literature that poor representation of Salix in the pollen spectra results from the low resistance of its exine after sedimentation (Bradshaw 1978). It remains unclear whether Pinus was growing in the Strandza Mountains during that time. Taking into consideration the over-representation of pine pollen in the pollen spectra, the presence of Pinus with nearly 20% testifies to a partial long distance transport. Analogous inference comes also from the investigations of surface moss pollen samples from the Balkan Range (Filipovitch and Lazarova 1997) but it is not impossible for Pinus to have formed small stands together with Betula at higher altitudes. Juniperus and Ephedra had also participated in the vegetation cover. The find of Juglans pollen since the beginning of the Preboreal presumes that walnut was preserved along the Bulgarian Black Sea coast during the Lateglacial as concluded by Bozilova (1986). The distribution of periodically flooded forests with Alnus and some Fraxinus on moist soils was still restricted. The pollen record suggests a reversion of the herb vegetation. Gradually, towards the end of the Preboreal, Artemisia and Chenopodiaceae were replaced by Poaceae and other herb species. PAZ V-2 According to the radiocarbon chronology the time span of this zone is between 9000 and 8355 BP and can be correlated with the Boreal period. The ratio AP/NAP indicates that the arboreal vegetation has become denser due to the continuation of the climate improvement (Bozilova 1986). Corylus continued to increase until the end of the period and was quite common in the undergrowth of the mixed oak forests. Probably, it formed also communities on open areas demonstrating a high pollen production and capability of long distance pollen dispersal (Andersen 1970). Comparably high values for Corylus were recorded in other pollen diagrams from the western part of the Black Sea (Filipova et al.

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1989; Atanassova 1995). According to Willis (1994) Corylus increased in the Balkans simultaneously with Ulmus, Tilia, Fraxinus excelsior around 8000 to 7000 years BP but in the Strandza Mountains the increase of this species has started earlier c. 9900 BP. Throughout this period a pronounced decrease in the presence of Pinus and Betula pollen accompanied by a rise of Quercus, Corylus, Ulmus, and to a certain extend of Tilia and Fagus, is also observed. The considerable presence of Ulmus corroborates the statement of Stojanov (1950) that in the past elm forests had played an important role in the composition of the vegetation in the Bulgarian lowlands. The presence of Carpinus betulus was still restricted but its increase as an admixture of the oak forests started from the beginning of the Boreal. The areas occupied by Fagus also enlarged. The find of pollen grains of Hedera, Vitis and Humulus/ Cannabis, considered as species sensitive to higher air humidity and temperature ( Iversen 1944), confirms that climate has improved. The presence of single pollen grains of Taxus suggests that this species was growing in close proximity to the area investigated during the last glaciation and appeared c. 8580±70 BP. At the same time Ephedra distachya, a shrub commonly associated with the Lateglacial in Europe (Iversen 1951), disappears in the pollen record but nowadays it can be found along the coast. PAZ V-3 The 14C date 8355±75 BP and the maximal values of tree pollen indicate a vast spread of the forest vegetation by the end of Boreal and during the Holocene climatic optimum, i.e. Atlantic period. The exceptionally high values of deciduous pollen suggest that the forests have become denser with a fairly closed canopy. Several oak species, mainly Quercus cerris, Quercus frainetto and Quercus polycarpa, were the dominant constituents of the balanced mixed oak communities in which also participated Corylus, Ulmus, Tilia, Fraxinus and Acer. The transition Boreal/Atlantic is defined as the level where Corylus started to decrease and Quercetum-mixtum became widespread. When the forest cover became denser, this probably caused a diminishing of Corylus blossoming with subsequent restriction in its distribution under the canopy. The beginning of Ulmus decline coincides with the appearance of pollen of anthropophytes such as Cerealia-type, Plantago lanceolata and Polygonum aviculare. However, this decline was not accompanied by a decrease in Tilia. This fact can be explained by a slight human interference in this unfavourable for agriculture region during the Eneolithic (6100–5850 BP). Traces of human activity in the pollen diagrams from Lake Arkutino and the Bay of Sozopol are more clearly expressed (Bozilova and Beug 1992; Filipova–Marinova and Bozilova 2002). Taking into account the limited possibilities of Tilia pollen for air dispersal, apparently this species was one of the main components of the mixed oak forests during that time. The presence of Fraxinus excelsior and Acer, though with single pollen grains, also suggests their participation in the forests. Carpinus betulus became more abundant within the mixed oak forests than before. The submediterranean elements such as Carpinus orientalis, Fraxinus ornus and Phillyrea grew most probably near to the coast. The increase of Carpinus

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orientalis can also be explained as a result of human impact. A comparison with the presentday situation along the coast shows that oriental hornbeam has enlarged on areas formerly occupied by oaks after their destruction by Man (Bondev 1991). A characteristic feature of the Holocene vegetation history was the early increase of Fagus in that area. In contrast to other parts of the coast, beech forests, most probably of Fagus orientalis, started to spread after 8355±75 BP. According to Bottema (1974) the increase of Fagus was mainly the result of higher precipitation. The distribution of Alnus comes simultaneously with the presence of pollen grains of Rhododendron and some lianas such as Hedera, Vitis and Humulus/Cannabis, thus testifying to an increase of humidity and temperature in the study area as well. The presence of Ericaceae pollen points to the spread of Vaccinium and Calluna. PAZ V-4 The upper boundary of this zone is dated at 3690±70 BP and can be correlated with Subboreal time. In general, during this period oak woodlands prevailed but a change in the composition of the vegetation was noticed. The pollen record reflects a trend towards an increase in the participation of Carpinus betulus in the mixed oak forests. The increase in the distribution of this tree was characteristic not only for the southern Bulgarian Black Sea coast but for the whole coastal area as well. Gradually, hornbeam expanded in northern direction. The maximum of Carpinus betulus was dated in the pollen diagrams from Lake Arkutino at 5680±65 BP(Bozilova and Beug 1992), from Lake Shabla-Ezeretz at 5650±100 BP (Filipova 1985), and from the deep-sea core MC-544 at 5280±190 BP (Filipova et al. 1989). A period of vast spread of hornbeam at that time was also established for the Balkan Range (Filipovitch et al. 1998). The beech forests, most probably Fagus orientalis, also enlarged their distribution along the humid ravines in the Strandza Mountains. A similar picture, dated at 5680±65 BP, was obtained from the pollen record of Lake Arkutino. Along the northern coast the spread of Fagus started later and its expansion maximum was reached at the beginning of the Subatlantic around 3070±100 BP in the area of Lake Shabla-Ezeretz (Filipova 1985), somewhat earlier at 4090±90 BP in the area of Lake Durankulak (Bozilova and Tonkov 1998), whereas in the area of the Danubian Lake Srebarna this event was dated at 2660±100 BP (Lazarova and Bozilova 2001). The diminishing of Ulmus and Tilia pollen coincides with a maximum in the spread of Carpinus orientalis and with an increase in the presence of the anthropogenic pollen indicators, Cerealia-type included, during the Bronze Age (5000–2800 BP) (Todorova 1981). PAZ V-5 This pollen zone reflects the vegetation history after 3690±70 BP. The main feature of the vegetation dynamics was the shaping of the present-day plant cover of the Strandza Mountains and along the Veleka river estuary. The mixed oak and hornbeam forests slightly decreased, most probably due to the human activity during the Iron Epoch, confirmed by

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the presence of pollen of Cerealia-type and anthropophytes as Plantago lanceolata, Polygonum aviculare, Carduus-type, Urtica and Filipendula. Probably, only small patches of land along the river and the coast were used for agriculture. The most characteristic event was the formation of the contemporary hydromesophytic over-flooded “longoz” forests along the river valley composed of Alnus, Ulmus, Fraxinus and Salix, with several lianas such as Hedera, Vitis, Humulus, Cannabis. In the area of Lake Arkutino, Ropotamo river, this forest type began to develop after 3255–3185 BP (Bozilova and Beug 1992). The history of the Veleka river firth The time span of the lower part of the sequence according to the radiocarbon chronology is between 9945±160 BP and 8355±75 BP (PAZs V-1 and V-2). The sediments are darkgrey to dark-brown sandy-aleuritic silts, and sandy-silty aleurit with a low organic content and sporadic occurrences of molluscan fauna and dinoflagellate cysts. In addition, the composition of the molluscan fauna with the predominance of the brackish-water species Dreissena polymorpha, the presence of the stenohalinous dinoflagellate species Spiniferites cruciformis, and the low MII (Fig. 4) suggest a comparatively low water salinity and confirm the Early Holocene age of the sediments. During that time an accidental ingress of the sea into the firth occurred, proved by the find of single specimens of the euryhalinous gastropod species Hydrobia ventrosa together with the molluscan species Cardium edule, and the euryhalinous dinoflagellate cysts Lingulodinium machaerophorum and acritarch Cymatiosphaera globulosa at some levels. The next molluscan-dinoflagellate unit comprises the interval 2380-1040 cm (PAZ V-3 and the beginning of PAZ V-4) where the dark-grey sandy-silty sediments appeared rich in organic material, and with a very high carbonate content. The latter originates from the high amount of molluscs. These sediments are characterized by the mixed euryhalinous mediterranean molluscan fauna (Hydrobia ventrosa) and the relict Caspian freshwater–brackish (Monodacna caspia caspia) (Fig. 5). On this background the fluctuations of freshwater with predominance of Dreissena polymorpha are explicable. The presence of the gastropod species Valvata sp. indet. emphasizes again the freshwater character of the sediment. In other layers of the sequence the euryhalinous Mediterranean species Abra ovata and Cardium edule predominate. The typical marine euryhalinous dinoflagellate cysts of Lingulodinium machaerophorum and acritarchs Cymatiosphaera globulosa are not identified in all studied layers and give ground to suggest an oscillatory connection of the firth with the sea (Fig. 4), confirmed also by the fluctuations of the MII for this unit. A steady mutual water-mass exchange between both basins was established during the third molluscan-dinoflagellate unit in the sediment interval 1040-350 cm. Sandy deposits with typical molluscan fauna of Mytilus galloprovincialis and Hydrobia ventrosa were found. In addition, Mytilaster lineatus, Corbula maeotica and Cerastoderma edule occurred. The proportion of haline faunal elements rises in the upper part of the sequence and suggests a Late Holocene age (the end of PAZ V-4 and PAZ V-5). The typical euryhalinous dinoflagellate

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Fig. 5. Distribution of the molluscan communities in core C-149 (analyzed by V. Shopov).

cysts Lingulodinium machaerophorum and acritarchs Cymatiosphaera globulosa are identified in all layers above 1040 cm. The MII sharply increases and testifies to the permanent connection of the firth with the sea. Most probably, this connection was established during the New Black Sea Transgression (5700–4000 BP) when the sea level rose with 3-4 m above the present-day situation (Chepalyga 1984). CONCLUSIONS 1. The investigated sediments from the flooded terrace of the firth estuary of the Veleka river were accumulated during the last c. 14C 10000 years. 2. The palaeoecological record reveals the Holocene environmental changes in the coastal part of the Strandza Mountains, Southeastern Bulgaria.

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3. The palynological evidence suggests that open deciduous forests were already established in the Strandza Mountains at the beginning of the Holocene. This gives ground to presume the existence of lateglacial refugia for some temperate tree taxa. 4. The human influence in the study area has been very weak. 5. The formation of the coastal firth of the Veleka river started at the beginning of the Holocene and was connected with the marine transgressions. ACKNOWLEDGEMENTS It is my pleasure to dedicate this paper on the occasion of Prof. Elissaveta Bozilova’s jubilee and to thank her for our fruitful cooperation for so many years. I am indebted to Prof. T. Krastev from the Institute of Oceanology, Varna, for the opportunity to investigate this material and for the description of the core lithology. Prof. M. Geyh from the Niedersäshsisches Landesamt für Bodenforschung, Hannover, Germany, kindly provided the radiocarbon dates. I am thankful to the late Prof. V. Shopov from the Institute of Geology, Bulgarian Academy of Sciences, Sofia, for the analysis of the molluscan fauna. REFERENCES Andersen STh (1970) The relative pollen productivity and pollen representation of North European trees and correction factors for tree pollen spectra. Danm Unders 2: 96-99. Atanassova J (1990) Late Quaternary vegetation development based on data from spore-pollen analysis of sediments from the western sector of the Black Sea. Ph. D. Thesis. Sofia University (in Bulgarian with English summary). Atanassova J (1995) Palynological data of three deep water cores from the western part of the Black Sea. In: Bozilova E, Tonkov S (eds) Advances in Holocene Palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 68-83. Atanassova J, Tonkov S, Bozilova E, Filipova M (2002) Palynological investigation of Holocene sediments from Lake Burgass. Ann Sofia Univ, Fac Biol 92, 2: 127-138. Bennett KD, Tzedakis PC, Willis KJ (1991) Quaternary refugia of north European trees. J Biogeogr 18: 103-115. Beug HJB (1982) Vegetation history and climatic changes in central and Southern Europe. In: Harding A (ed) Climatic changes in Later Prehistory. Edinburgh Univ Press, pp 85-102. Birks HJB (1986) Late-Quaternary biotic changes in terrestrial and lacustrine environments, with particular reference to Northwest Europe. In: Berglund BE et al. (eds) Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley & Sons, Chichester, pp 3-52. Birks HJB, Birks HH (1980) Quaternary palaeoecology. Edward Arnold Ltd, London. Bondev I (1991) The vegetation of Bulgaria. Map 1: 600 000 with explanatory text. Univ Press St. Kliment Ohridski, Sofia (in Bulgarian with English summary). Bottema S (1974) Late Quaternary vegetation history of Northwestern Greece. Thesis, Gröningen.

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Bottema S (1990) Notes on the history of the Genus Betula in Turkey during the Late Quaternary. Ecol Mediter 14: 145-150. Bozilova E (1982) Holocene chronostratigraphy in Bulgaria. Striae 16: 88-90. Bozilova E (1986) Palaeoecological Conditions and Vegetation Changes in Eastern and Southwestern Bulgaria During the Last 15 000 years. Dr. Sc. Thesis, Sofia University (in Bulgarian with English summary). Bozilova E (1995) The upper forest limit in the Rila Mountains in Postglacial time: Palaeoecological evidence from pollen analysis, macrofossil plant remains and 14C dating. In: Bozilova E, Tonkov S (eds) Advances in Holocene palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 1-8. Bozilova E, Beug H-J (1992) On the Holocene history of vegetation in SE Bulgaria (Lake Arkutino, Ropotamo region). Veget Hist Archaeobot 1: 19-32. Bozilova E, Smit A (1979) Palynology of Lake “Sucho Ezero” from South Rila Mountain (Bulgaria). Fitologija 11: 54-67. Bozilova E, Tonkov S (1998) Towards the vegetation and settlement history of the southern Dobrudza coastal region, north-eastern Bulgaria: a pollen diagram from Lake Durankulak. Veget Hist Archaeobot 7: 141-148. Bozilova E, Tonkov S (2000) Pollen from Lake Sedmo Rilsko reveals southeast European postglacial vegetation in the highest mountain area of the Balkans. New Phytol 148: 315-325. Bozilova E, Filipova–Marinova M (1994) Palaeoecological conditions in the area of the praehistorical settlement of Urdovitza near Kiten. Thracia Pontica V, Sozopol, 39-51. Bozilova E, Atanassova J, Filipova–Marinova M (1997) Marinopalynological and archaeological evidence for the Late Glacial and Holocene vegetation in Eastern Bulgaria. Ann Sofia Univ, Fac Biol 89, 2: 69 - 81. Bradshaw RH (1978) Modern pollen representation factors and recent woodland history in Southeastern England. Ph.D. Thesis, Cambridge University. Chepalyga A (1984) Inland sea basins. In: Velichko A (ed) Late Quaternary environments of the Soviet Union. Minnesota Univ Press, Minnesota, pp 229-247. Faegri K, Iversen I (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester. Filipova M (1985) Palaeoecological investigations of Lake Shabla – Ezeretz in North-Eastern Bulgaria. Ecol Mediter 11, 1: 148-158. Filipova–Marinova M (1995) The Late Quaternary history of the genus Fagus L. in Bulgaria. In: Bozilova E, Tonkov S (eds) Advances in Holocene Palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 84-95. Filipova–Marinova M, Bozilova E (2002) Palaeoecological conditions in the area of the praehistorical settlement in the Bay of Sozopol during the Eneolithic. Phytologia Balcanica 8 (2): 133-143. Filipova M, Bozilova E, Dimitrov P (1989) Palynological investigation of the Late Quaternary deepwater sediments from the Southwestern part of the Black Sea. Bulletin du Museé National de Varna 25 (40): 177-181. Filipova M, Bozilova E, Tonkov S (1993) Palynology of submerged archaeological sites along the Bulgarian Black Sea coast. PACT, Belgium, 47-II.1: 43-51.

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Filipovitch L (1981) Late Postglacial development of forest vegetation on the high slopes of the Stara Planina Mountain. Fitologija 33: 23-33. Filipovitch L, Lazarova M (1997) Surface pollen samples from the high altitude slopes of Stara Planina (The Balkan Range). Phytologia Balcanica 3/2-3: 41-52. Filipovitch L, Lazarova M (2001) Composition and trends in the development of vegetation in the Wetern Rhodopes (Southwestern Bulgaria) during the Late Glacial and Holocene. Phytologia Balcanica 7, 2: 167-180. Filipovitch L, Stefanova I, Lazarova M, Petrova M (1997) Holocene vegetation in Stara Planina (The Balkan Range). Phytologia Balcanica 4 (1-2): 13-25. Grimm E (1991) Tilia and Tilia-graph. Illinois State Museum, Springfield, USA. Huntley B, Birks HJB (1983) An atlas of past and present pollen maps of Europe 0-13 000 years ago. Cambridge Univ Press, Cambridge. Iversen J (1944) Viscum, Hedera and Ilex as climatic indicators. Geol Foren Forh 66: 463-483. Iversen J (1951) Steppeelementer I den senglaciale Flora og Fauna. Meddelelser fra Dansk. Geol Foren 12: 1-174. Jordanov D (1939) Plant relationships in the Bulgarian part of the Strandza Mountains. Ann Sofia Univ, Fac Phys-Math 3: 1-90 (in Bulgarian). Lang G (1970) Florengeschichte und mediterran-mitteleurepaische Florenbeziehungen. Fedd Repert 81: 315-335. Lang G (1985) Palynologic and stratigraphic investigations of Swiss lake and mire deposits. A general view over a research program. Diss Bot 87: 107-114. Lazarova M, Bozilova E (2001) Studies on the Holocene history of vegetation in the region of Lake Srebarna (North-East Bulgaria). Veget Hist Archaeobot 10: 87-95. Markova M, Ancev M, Peev D (1982) Status of the flora and tendencies of its development in the Silkosia Reserve in the Strandza Mountains. In: Proceedings of the National Theoretical Conference on Protection and Recreation of the Environment, Golden Sands, 1-5 November 1982, pp 98-103 (in Bulgarian with English summary). Mikhailov T (1989) Elevation groups and types of mountains. In: Mishev K (ed) Natural and economic potential of the mountains in Bulgaria. I. Nature and resources. Bulg Acad Sci, Sofia, pp 18-25 (in Bulgarian). Penev I (1984) Longoz forests along the Bulgarian Black Sea coast. Ann Sofia Univ, Fac Biol 74, 2: 113-120 (in Bulgarian). Popov V, Mishev K (1974) Geomorhology of the Bulgarian Black Sea coast and shelf. Bulg Acad Sci, Sofia (in Bulgarian). Sabev L, Stanev S (1963) Climatic zones in Bulgaria and its climate. Zemizdat, Sofia (in Bulgarian). Shopov V (1991) Young-Quaternary molluscs stratigraphy of the outer Black Sea shelf. Compt Rend Bulg Acad Sci 31, 7: 893-897. Shopov V (1992) Pattern of the Quaternary Development of the Bulgarian Black Sea shelf. Compt Rend Bulg Acad Sci 45, 2: 55-58. Stefanov B (1924) Forest formations in the Northern Strandza Mountains. Ann Sofia Univ, Fac Agron 5: 23-68 (in Bulgarian).

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Stefanova I, Bozilova E (1995) Studies on the Holocene history vegetation in the Northern Pirin Mountains (Southwestern Bulgaria). In: Bozilova E, Tonkov S (eds) Advances in Holocene palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 9-31. Stojanov N (1928) Longoz forest along the Kamchia river and the longoz forests as a plant formation. Forest Review 7-8: 1-26 (in Bulgarian with German summary). Stojanov N (1941) An attempt for characterization of the main phytocoenosis in Bulgaria. Ann Sofia Univ, Fac Phys-Math 3: 1-26 (in Bulgarian). Stojanov N (1950) Phytogeography. Nauka i Izkustvo, Sofia (in Bulgarian). Stuiver M, Reimer P (1993) Extended 14C data base and revised CALIB 3.0 14C age calibration program. Radiocarbon 35: 215-230. Tishkov H (1989) Bioclimatic potential of the mountains in Bulgaria. In: Mishev K (ed) Natural and economic potential of the mountains in Bulgaria. I. Nature and resources. Bulg Acad Sci, pp 117-129 (in Bulgarian). Todorova H (1981) Eneolithic in Bulgaria. Sofia Press, Sofia (in Russian). Tonkov S, Panovska H, Possnert G, Bozilova E (2002) The Holocene vegetation history of Northern Pirin Mountain, southwestern Bulgaria: pollen analysis and radiocarbon dating of a core from Lake Ribno Banderishko. Holocene 12, 2: 201-210. Traverse A (1978) Supplementary palynological information from site reports for DSDP LeG. 43 B. Initial Reports of Deep Sea Drilling Project XLII, 2: 29-305. Velchev V, Peev D, Vassilev P (1985) Status and problems of the protection of the endangered and rare plant communities in the Strandza-Sakar Region. Ecologia 17: 3-10 (in Bulgarian). Welten M (1992) Vegetationsgeschichtliche Untersuchungen in den westlichen Schweizer Alpen: Bern-Wallis. Denkschr Schweiz Natf Ges 95. Willis KJ (1994) Vegetation history of the Balkans. Quat Sci Rev 13: 769-788.

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© PENSOFT Publishers A 5000-year Sofia - Moscow

Spassimir Tonkov (ed.) 2003 pollen record from Osogovo Mountains, Southwestern Bulgaria 233 Aspects of Palynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 233-244

A 5000-year pollen record from Osogovo Mountains, Southwestern Bulgaria Spassimir Tonkov Laboratory of Palynology, Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria E-mail: [email protected]

ABSTRACT This palynological study aims to shed light on the vegetation history and human impact during the last c. 5000 years in the Osogovo Mountains, Southwestern Bulgaria, an area that has been insufficiently studied. The palaeovegetation reconstruction, supported by a reliable radiocarbon chronology, revealed the existence of a characteristic mid-Holocene vegetation pattern dominated by conifers (Pinus sylvestris, Pinus nigra and Abies alba) that covered the high mountain slopes between c. 5000 and 2200 cal. BP. The pollen assemblages for the time interval 2200–720 cal. BP recorded an important change in the forest composition that has led to the replacement of the conifers, mostly Abies alba, by invading communities of Fagus. Quite probably, the reasons for this replacement, that started at the transition Subboreal/ Subatlantic, were of a complex character and included factors relating to both climate change and anthropogenic disturbance. During the last centuries a widespread degradation of the natural woodlands has occurred and the present-day appearance of the vegetation cover of the Osogovo Mountains was shaped. The palynological evidence indicative of human impact in the study area is correlated with the available information from archaeological and historical sources since the Early Bronze Age. KEY WORDS: Pollen analysis – Vegetation history – Human impact – Osogovo Mountains – Southwestern Bulgaria

INTRODUCTION The montane part of Southwestern Bulgaria is traditionally known as one of the important and key areas for palynological and palaeoecological research on the postglacial flora and vegetation history of the Balkan peninsula. A great many of the recent investigations have been conducted on lateglacial and Holocene lake and peat bog sequencies

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from the high Rila Mountains (2925 m) and Pirin Mountains (2914 m) that were both glaciated at least twice during the Quaternary (Bozilova 1981, 1995; Bozilova et al. 1990; Stefanova and Bozilova 1995; Bozilova and Tonkov 2000; Tonkov et al. 2002; Tonkov 2003; Stefanova and Ammann 2003, etc.). The other main research trend in this montane area has been focused on the postglacial vegetation and environmental development in the non-glaciated western border OsogovoBelasitsa mountain range (Bozilova and Tonkov 1985; Panovska et al. 1990; Tonkov and Bozilova 1992; Tonkov 1992, 1994, 2001). This mountain range stretches longitudinally westwards from the Rila and Pirin Mountains along the course of the Struma river and was also one of the main routes for tree migrations in postglacial time from the mountains in Northwestern Greece to the central and northern parts of the Balkan peninsula (Bozilova and Tonkov 1985, 1994) (Fig. 1). The present paper expands on an earlier publication on the Holocene vegetation history of the Osogovo Mountains which was confined to the last 1500 years (Tonkov 1994). The

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Rousse

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Plovdiv

Black Sea

43

S

3 4

. Mts Pirin

F.Y.R.O.M.

42

Turkey

5 6

Greece

Fig. 1. Map of Bulgaria showing the location of sites in the Osogovo-Belasitsa mountain range mentioned in text: Osogovo Mts. - S the study site, 1 Osogovo-2 (Tonkov 1994); 2 Tschokljovo marsh, Konjavska Mts. (Tonkov and Bozilova 1992a); 3 Vlahina Mts. (Tonkov 1992); 4 Maleshevska Mts. (Tonkov and Bozilova 1992); 5 Belasitsa Mts. (Panovska et al. 1990); 6 Belasitsa (Beles) Mts. (Athanasiadis et al., this volume).

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new palynological information fills in a gap in our knowledge on the main trends in vegetation development and human impact during the last c. 5000 years. THE STUDY AREA Osogovo Mountains (2251 m) is the highest, northernmost border massif of the Osogovo-Belasitsa mountain range, situated in Southwestern Bulgaria and Northeastern F.Y.R. of Macedonia. On bulgarian territory the northern and northeastern slopes are steep and to the south the saddle of Red Rock is the linkage to the Vlahina Mountains (1924 m). Geologically, the massif is composed mainly of Palaeozoic metamorphic and intrusive rocks. The climate below an altitude of 1000 m is moderate continental. Above this altitude it is typically montane with mean annual precipitation of 700-900 mm. The average annual duration of the stable snow cover is 135 days. The basic soil types are cinnamomic-forest, brown-forest and mountainous dark-forest. The modern vegetation of the Osogovo Mountains is in several vegetation belts. The oak forest belt up to 1000 m on southeastern slopes is dominated by Quercus pubescens, Quercus cerris and Quercus dalechampii, with some Carpinus orientalis, Ostrya carpinifolia and Juniperus oxycedrus. The beech belt (1000-1900 m) is the most well-developed vegetation belt composed mainly of monodominant communities of Fagus sylvatica. In some areas between 1500 and 1900 m beech forms the upper tree-line, and at present a compact coniferous vegetation belt does not exist. The coniferous forest communities are fragmented, quite often patches of Pinus nigra and Abies alba are found between 900 and 1700 m within the beech forests. Stands or isolated trees of Pinus sylvestris grow close, or just above the treeline. Remnants of mixed coniferous communities composed of Picea abies and Abies alba, highly restricted in distribution, are preserved in the northern part of the mountain between 1100 and 1600 m. The treeless areas in the subalpine belt, above the beech forests, are occupied by plant communities of Juniperus sibirica, Chamaecytisus absinthioides, Vaccinium myrtillus, Nardus stricta, etc. In all vegetation belts the negative consequencies of long-lasting anthropogenic activities, including ore-mining industry and deforestation with subsequent erosion, are easily identified (Zahariev 1934; Velchev and Tonkov 1986). In the treeless central part of the mountain between 1600 and 1800 m, just above the tree-line, numerous peat bogs occur along streams and in depressions. In most of them the thickness of the sediments hardly reaches 80-100 cm. After careful selection a peat bog named Osogovo-1 (1720 m asl) was chosen for the present palynological study. The bog itself is situated in a depression and occupies an area of several hundred square meters on a northeastern-facing slope. Stands of Pinus sylvestris and Juniperus communis grow nearby and Picea abies was planted.

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MATERIAL AND METHODS Pollen analysis A core 170 cm deep was taken with a Dachnowsky hand-operated corer. The peat sediment samples for pollen analysis were taken at 10 cm intervals and were processed by standard methods including HCL, HF and acetolysis (Faegri and Iversen 1989). Almost all samples yielded well preserved pollen grains. The identification of the subfossil pollen types and spores was performed using the reference collection of the Laboratory of Palynology in Sofia, the keys in Beug (1961), Faegri and Iversen (1989) and Moore et al. (1991). The pollen sum (PS) used for percentage calculations was based on total terrestrial pollen (arboreal pollen (AP)+non-arboreal pollen (NAP)) excluding spores of mosses and pteridophytes and pollen of Cyperaceae. In most cases a PS of 550-650 was achieved. The percentage pollen diagram was constructed using the computer software Tilia and Tilia-graph (Grimm 1991) (Fig. 3). Taxa with low frequencies were not shown on the pollen diagram. The subdivision of the pollen diagram into three local pollen assemblage zones (LPAZ) was made by CONISS (Grimm 1987) and reflects successive stages in vegetation development. The zones are numbered from the base upwards and prefixed by the site designation OS. Radiocarbon dating Three 14C dates were performed on bulk peat samples in the Radiocarbon Dating Laboratory at the Deaprtment of Quaternary Geology, University of Lund, Sweden. The dates have been calibrated to calendar years with the computer program OxCal v3.5 Bronk Ramsey (2000). The corresponding calendar time intervals and associated probabilities are shown on Table 1. A depth-age curve reflecting the sedimentation pattern is constructed (Fig. 2). The estimates from the radiocarbon dating indicate a constant sediment accumulation rate of 38-39 yrs/cm for the interval 120-50 cm. A quicker rate of sedimentation (14 yrs/cm) is established for the last 700 years when 50 cm of peat was deposited. The age of the basal part of the sequence is estimated by linear interpolation at c. 5200–5000 BP. Table 1. Results of radiocarbon datings. Lab. No

Depth (cm)

Age (BP)

Calendar age (cal. BP)

Material dated

Lu-3420

45-55

790±60

peat

Lu-3421

82-98

2220±70

Lu-3422

120-130

3350±70

760 (0.68) 665 800 (0.95) 640 2330 (0.68) 2150 2350 (0.95) 2040 3640 (0.68) 3470 3730 (0.95) 3440

peat peat

A 5000-year pollen record from Osogovo Mountains, Southwestern Bulgaria

Depth (cm)

180

237

?

160 140 120 100 80 60 40 20 1

2

3

4

5

6

Millennia cal. BP Fig. 2. Age as a function of depth for core Osogovo-1.

RESULTS AND DISCUSSION Pollen stratigraphy The description of the pollen zones is briefly outlined: LPAZ OS-1 (170-95 cm, Pinus diploxylon - Abies) Pinus diploxylon-type dominates with 65-45% accompanied by Abies pollen with 8-10%. Juniperus, Alnus, Quercus, Tilia, Corylus and Carpinus pollen is represented at low values of 24% each. Pollen of Juglans is regularly found. The herb component is represented by Poaceae 5% and a number of taxa such as Cichoriaceae, Achillea-type, Cirsium-type, Dianthus-type, Lychnis-type, etc. A characteristic feature for the entire diagram are the high values of Scleranthus pollen reaching 15-20%. LPAZ OS-2 (95-55 cm, Pinus diploxylon - Fagus - Abies) In this zone pollen of Pinus diploxylon-type dominates at 45-50%. A local maximum of Abies pollen of 12% is followed by a decline to 3-4%. A peculiar feature of this zone is the quick rise of the Fagus pollen curve up to 30%. Pollen of Juniperus is also found with low frequencies. The pollen curves of Plantago lanceolata, Rumex and Chenopodiaceae are first established in this zone. LPAZ OS-3 (55-0 cm, Fagus - Pinus diploxylon - Poaceae) The pollen curve of Fagus attains a maximum of 50% (level 20 cm). The contribution of Pinus diploxylon-type quickly declines to 15% while pollen grains of Abies are scarcely found. Deciduous tree pollen increases mainly due to Quercus 6-8%, Carpinus orientalis/Ostrya 34%, Corylus and Betula.. Juniperus pollen shows higher frequencies in the uppermost samples. In this zone pollen of Poaceae reaches 15% (level 40 cm) accompanied by Artemisia, Brassicaceae, Apiaceae, Veratrum-type, etc. A continuous pollen curve is recorded for Secale.

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s nu Pi

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ox pl di

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Fig. 3. Percentage pollen diagram Osogovo-1.

3350 ± ¸ 70

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C 14

P .B rs

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Peat Bog OSOGOVO-1 /1720 m asl, Osogovo Mts./

Depth (cm)

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us rc a e u li Q Ti

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OS-3

ya pe str O -ty / a s i s i l b lat u s ta na e eo u l ien n c p t e or Ca lan hu s -ty sb s s/ m s s u m x ag o an t lu in iu eae n lu p in u p in u la s e e u l e t a r y d c r r r tu nu lix g l tis um cc a ca r m an le C o C a C a Be A l Sa Ju Vi H Va P o S e Ho Ru P l S c Zone

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238 Spassimir Tonkov

P s.B

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170

Fig. 3. Continued.

3350 ±¸ 70

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790 ±¸ 60

C 14

yr

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Analyst: Spassimir Tonkov

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OS-1

OS-2

OS-3

pe rta -ty ae pe a sto e ce i ty eae e e e c b pe pe e e p pe ea ia c e s p e p e ja d ia eae yp ea -ty ty y p eae m iac ium m lu -ty ty la -t p e lar la p ty y a um u d ir ac isia ea- m-t ure o p o icac tru ncu hus is- d u tilla -ty la ia o sa hu anu -ty eae o n ana rum lla- a-t r ac gn po ch e th e n en n m u ut i p p m c g ti t o m ill iu ta n s lic u t h a ly try ch te h rs n e as a n an ch lip te u im a ab ro m liu ia ly n r a un en p C i A r A c C i C e C h Br Th Ra Di Ly F i P o Ge P r Kn Sc Sc C a Ga A p P o Ge Ve P r M C y S p P o Bo Zone

40

Total sum o

20

CONI

A 5000-year pollen record from Osogovo Mountains, Southwestern Bulgaria

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Vegetation history The palynological results from the peat profile, in conjuction with the radiocarbon dates, provide a reliable basis for a palaeovegetation reconstruction of the central part of the Osogovo Mountains for the last c. 5000 years. The oldest pollen spectra (zone OS-1) reflect a characteristic mid-Holocene vegetation pattern that has existed from the end of the Atlantic throughout the entire Subboreal chronozone. In particular, the high mountain slopes and flat ridges were covered by coniferous vegetation dominated by pines (Pinus sylvestris, Pinus nigra) and silver fir (Abies alba). The share of each tree in this forest belt could be approximately evaluated from results of pollen analysis of surface moss samples collected from modern coniferous plant communities. For example, Pinus sylvestris and Pinus nigra demonstrate high pollen over-production and are capable of effective dispersal, while 1015% of Abies pollen (as in zone OS-1) indicates up to 30-40% of Abies in the composition of a mixed coniferous forest (Tonkov et al. 2000). It is well-known that the pollen grains produced by Pinus mugo (dwarf-pine) also belong to the group Pinus diploxylon-type and can not be distinguished by morphological features. Currently, the hypothesis for a probable past distribution of dwarf-pine in the highest parts of the Osogovo Mountains remains unconfirmed until reliable proof is obtained by finding plant macrofossils. Regarding the occasional finds of single pollen grains of Picea, these are more likely to be the result of long-distance transport, rather than a local restricted distribution. Obviously, the peat bog was included within the coniferous forest belt and the input of deciduous tree pollen was quite low. The broad-leaved vegetation was distributed at lower altitudes, composed of different Quercus species, Carpinus, Tilia and Corylus. In habitats with higher humidity grew groups of Fagus and Alnus and Salix were found along streams and brooks. According to the radiocarbon chronology, this vegetation pattern in the Osogovo Mountains has lasted for nearly 3000 years, i.e. until 2200 cal. BP. It is interesting to compare these results with previous investigations from other sites in the Osogovo-Belasitsa mountain range. The palynological record from the Maleshevska Mountains (Tonkov and Bozilova 1992) showed an expansion of Abies after 7300 cal. BP (>30% pollen) resulting in the formation of a coniferous Abies-Pinus belt above 1300 m dominated by fir. A second maximum (~20%) of Abies, which represents a readvance, occurred between 3400 and 2700 cal. BP just like the situation in the Osogovo Mountains. In the Konjavska Mountains (1487 m), located northeastwards of the Osogovo range, the stands of Abies gradually formed into an almost pure Abies belt, with some Pinus after 7200 cal. BP. The period of Abies stability lasted between 6800 and 3300 cal. BP (Tonkov and Bozilova 1992a; Bozilova and Tonkov 1994). The pollen record of the next stage in vegetation development (zone OS-2, 2200–720 cal. BP) revealed an important change in the forest composition. In the course of a thousand years Fagus has replaced the dominant conifers (Abies and Pinus) on many areas thus producing a vegetation belt where Fagus was either the single dominant or grew mixed with

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conifers. This replacement started at the transition Subboreal/Subatlantic when the climate became more humid and cooler, and average temperatures decreased. Quite probably, the reasons for this replacement were of a more complex character and anthropogenic impact should also be taken into consideration. It is thought that the clearings made by the local population have most strongly affected the communities of Abies alba. The expansion phase of Fagus in the central part of the Osogovo Mountains started shortly after 930 cal. BP (Tonkov 1994). Moving southwards along the Osogovo-Belasitsa mountain range, the pollen record from the Maleshevska Mountains shows that Fagus started to extend after 2760 cal. BP (Tonkov and Bozilova 1992). In the peat sequence from the Belasitsa Mountains high values (~25%) of Fagus pollen were present at 1780 cal. BP (Panovska et al. 1990). This review of the pollen evidence derived from all these regional sites undoubtfully confirms that the formation of the present-day Fagus vegetation belt in the western border mountains has started more or less synchronously around the beginning of the Subatlantic chronozone, implying also migration in northern direction. Parallel to the development of the beech forests in the Osogovo Mountains, signs of a partial restoration of Carpinus and Quercus communities at lower altitudes are observed in the pollen diagram. During the last 700 years there has been a general trend towards a progressive decline in the distribution of the conifers, namely Pinus, in the forest cover (zone OS-3) culminating in their present-day fragmentary state. This large-scale destruction of the coniferous vegetation was caused by increasing anthropogenic activities that led to deforestation and extension of the pasture land. The pollen record for this time interval contains high quantities of Poaceae and Juniperus pollen. Tree felling and fire clearances were practised to enlarge the areas used for seasonal cattle-breeding. Fragments of the coniferous forests were preserved within the expanding beech belt, above it, or alongside river valleys in isolated and inaccessible places. The expansion of Fagus in the Osogovo Mountains reached a maximum at c. 1600 cal. AD. A similar age for this final expansion (290±95 BP, 1660 cal. AD) was established from a peat profile on Greek territory in the Belasitsa (Beles) Mountains (Athanasiadis et al., this volume). Obviously, the maximal distribution of Fagus several centuries ago in all parts of the Osogovo-Belasitsa mountain range was synchronous, and primarily controlled by climatic reasons. It is therefore tempting to find temporal correspondence between the expansion of Fagus and the duration of the Little Ice Age c. 1500–1850 AD (Grove 1988) when average temperatures dropped and humidity increased. On the other hand, local disturbances caused by human interferences were also important for Fagus establishment. The last two centuries marked a total degradation of the woodlands in the Osogovo Mountains when the beech forests were also subjected to intensive exploitation and the tree-line was artificially lowered to its present-day level.

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Human impact From the archaeological and palaeoethnobotanical evidence, and partly from the pollen analyses, it has become evident that Southwestern Bulgaria was one of the first centers where Neolithic cultures had developed at the end of the seventh millenium BC. At that time settlements existed with developed stock-breeding and agriculture on both sides along the course of the Struma river in the mountainous zone below 800 m (Bozilova and Tonkov 1990). In the pollen diagrams from the Osogovo-Belasitsa mountain range the earliest traces of human influence were recorded c. 6800 cal. BP (Late Neolithic, Maleshevska Mountains) though with lower percentage values of Cerealia and the anthropogenic indicators. For this area the most characteristic pollen anthropogenic indicators recognized, alongside cereals, are Plantago lanceolata, Rumex, Scleranthus, Urtica and Juniperus. This group may also include part of the Poaceae, Artemisia and Chenopodiaceae pollen. Around 2700 cal. BP (Iron Age) a peak in the distribution of these indicators was registered. By that time the Thracian tribes along the Struma river had moved higher up into these mountains (Bozilova and Tonkov 1990; Tonkov and Bozilova 1992). In our palynological record from the Osogovo Mountains the pollen curve of Rumex appears first c. 3000 cal. BP (level 110 cm, Late Bronze Age) while the continuous participation of Secale, Plantago lanceolata and Juniperus starts much later c. 600–700 cal. AD. However, the high quantitities (10-20%) of Scleranthus pollen found particularly for the interval 170-50 cm merit attention. It is logical to suppose that these high values are of local/extralocal origin but on the other hand they are also indicative of stock-breeding practised by the local population. Abundant archaeozoological but little botanical evidence material was found in the cultural layers (Early Neolithic–Early Bronze Age) of the nearest prehistoric settlement Vaxevo located at 600 m asl in a southeastern direction from the study area. The bones from cattle, sheep, goats and pigs, and the absence of artefacts connected with cultivation (sickles, muttocks, etc.) prove that stock-breeding was more significant in the human economy rather than crop production (Chohadziev et al. 2001). According to the radiocarbon chronology, the lowermost part of the pollen diagram (170-120 cm) could be assigned to the Early and Middle Bronze Age, and thus correlates with the archaeological record. As already stated above, the continuous presence of the anthropogenic indicators in the pollen diagram is connected with the Thracian and Roman periods. At the end of the VIth century BC two Thracian tribes settled in the north-eastern foothills of the Osogovo Mountains and in the surrounding valleys. Agriculture, vine-growing, stock-breeding and ore-mining were developed. The mountain slopes served as an important source for wood used for construction purposes, heating and metallurgy. During the time of the Roman colonization the local economy flourished as the Romans introduced advanced methods for the cultivation of the fields (Bozilova et al. 1994). Since this period the cultivation of walnut (Juglans regia) in the area became widespread as established by the continuous pollen curve of Juglans. In medieval times, after 720 cal. BP, the impact of Man on the natural woodlands has drastically intensified as shown by the sharp decline of the pollen curve of

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Pinus diploxylon-type and the rise of Poaceae. The destruction of the coniferous forests also resulted in the enlargement of the treeless areas used for summer pasture land. The subsequent increase of Juniperus and the decline of Fagus during the last centuries confirm that the final stage in the destruction of the forest cover resulted in its present-day appearance. ACKNOWLEDGEMENTS I would like to dedicate this paper to Prof. Elissaveta Bozilova who introduced me to palynology and to thank her for the ideas and advice which encouraged me in the early 1980s to start investigations on the vegetation history of the western border of the Bulgarian mountains. The study area in the Osogovo Mountains was visited several times and I am indebted to Prof. E. Bozilova, Prof. M. Anchev, Dr. G. Angelov and Dr. S. Avramov for their help in the field work. Prof. B. E. Berglund and Dr. G. Skog from the Department of Quaternary Geology, University of Lund, Sweden, kindly provided the radiocarbon dates. Special thanks go to H. Tinsley, Bristol, UK, who was so kind as to check the English of the text. REFERENCES Beug H-J (1961) Leitfaden der pollenbestimmung fur mitteleuropa und angrenzende gebiete. Fischer, Suttgart. Bozilova E (1981) Vegetation changes in the Rila Mountains during the last 12000 years. Ann Sofia Univ, Fac Biol 71, 2: 37-44 (In Bulgarian with English summary). Bozilova E (1995) The upper forest limit in the Rila Mts. in postglacial time - palaeoecological evidence from pollen analysis, macrofossil plant remains and 14C dating. In: Bozilova E, Tonkov S (eds) Advances in Holocene Palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 1-8. Bozilova E, Tonkov S (1985) Vegetational development in the mountainous areas of Southwestern Bulgaria. I. Palynological investigations and reconstruction of past vegetation. Ecol Mediter 11 (1): 33-37. Bozilova E, Tonkov S (1990) The impact of Man on the natural vegetation in Bulgaria from the Neolithic to the Middle Ages. In: Bottema S, Entjes-Nieborg G, van Zeist W (eds) Man’s Role in the Shaping of the Eastern Mediterranean Landscape. Balkema, Rotterdam, pp 327-332. Bozilova E, Tonkov S (1994) The postglacial distribution patterns of Abies in Bulgaria. Diss Bot 234: 215-223. Bozilova E, Tonkov S (2000) Pollen from Lake Sedmo Rilsko reveals southeast European postglacial vegetation in the highest mountain area of the Balkans. New Phytol 148: 315-325. Bozilova E, Tonkov S, Pavlova D (1990) Pollen and plant macrofossil analyses of the Lake Sucho Ezero in the South Rila mountains. Ann Sofia Univ, Fac Biol 80, 2: 48-57. Bozilova E, Tonkov S, Popova Tz (1994) Forest clearance, land use and human occupation during the Roman colonization in Bulgaria. In: Frenzel B (ed) Palaeoclimate Research 10. Gustav Fischer Verlag, Stuttgart, pp 37-44.

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Bronk Ramsey C (2000) OxCal Program v3.5. University of Oxford, Radiocarbon Accelerator Unit. Chohadziev S, Genadieva V, Gjurova M, Popova Tz, Ninov L (2001) Vaxevo – Prehistorical Settlements. Faber, Veliko Turnovo (In Bulgarian with English summary). Faegri K, Iversen J (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester. Grimm E (1987) CONISS: A Fortran 77 Program for stratigraphically constraint cluster analysis by the method of incremental squares. Comput Geosci 13: 13-35. Grimm E (1991) Tilia and Tilia-graph. Illinois State Museum, Springfield, USA. Grove JM (1988) The Little Ice Age. Methuen, London. Moore P, Webb J, Collinson M (1991) Pollen analysis. Blackwell Science, Oxford. Panovska H, Bozilova E, Tonkov S (1990) Late Holocene vegetation history in the western part of Belasitza mountain. In: Geographica Rhodopica 2. Aristotle Univ Press, Thessaloniki, pp 1-7. Stefanova I, Bozilova E (1995) Studies on the Holocene history of vegetation in the Northern Pirin Mts. (Southwestern Bulgaria). In: Bozilova E, Tonkov S (eds) Advances in Holocene Palaeoecology in Bulgaria. Pensoft Publ, Sofia-Moscow, pp 9-31. Stefanova I, Ammann B (2003) Lateglacial and Holocene vegetation belts in the Pirin Mountains (southwestern Bulgaria). Holocene 13, 1: 97-107. Tonkov S (1992) Pollen-analytical investigation on the vegetation history in Vlahina mountain. Ann Sofia Univ, Fac Biol 81, 2: 22-30 (In Bulgarian with English summary). Tonkov S (1994) Pollen analysis of peat-bog in Osogovo mountain (Southwestern Bulgaria). Ann Sofia Univ, Fac Biol 85, 2: 63-68. Tonkov S (2001) On the history of the coniferous forests in Osogovo mountain (Southwestern Bulgaria). In: Naydenova Ts (ed) Proceedings Third Balkan Scientific Conference “Study, Conservation and Utilisation of Forest Resources”. Acad Publ “M. Drinov”, Sofia, pp 160-164. Tonkov S (2003) Holocene palaeovegetation of the Northwestern Pirin Mountains (Bulgaria) as reconstructed from pollen analysis. Rev Palaeobot Palynol 124/1-2: 51-61. Tonkov S, Bozilova E (1992) Pollen analysis of peat-bog in Maleshevska mountain (Southwestern Bulgaria). Ann Sofia Univ, Fac Biol 81, 2: 11-22 (In Bulgarian with English summary). Tonkov S, Bozilova E (1992a) Paleoecological investigation of Tschokljovo marsh (Konjavska mountain). Ann Sofia Univ, Fac Biol 83, 2: 5-16. Tonkov S, Bozilova E, Pavlova D, Kozuharova E (2000) Surface pollen samples from the valley of the Rilska Reka river, Central Rila Mountains (Southwestern Bulgaria). Ann Sofia Univ, Fac Biol 91, 2: 63-73. Tonkov S, Panovska H, Possnert G, Bozilova E (2002) The Holocene vegetation history of Northern Pirin Mountain, southwestern Bulgaria: pollen analysis and radiocarbon dating of a core from Lake Ribno Banderishko. Holocene 12, 2: 201-210. Velchev V, Tonkov S (1986) Vegetation and flora of Southwestern Bulgaria. In: Botev B (ed) Fauna of Southwestern Bulgaria. Part I. Bulg Acad Sci, Sofia, pp 20-43 (In Bulgarian with English summary). Zahariev B (1934) On the natural localities of the conifers in Osogovo mountain. Proceed Bulg Botan Soc VI: 10-35 (In Bulgarian with English summary).

© PENSOFT Publishers Late Sofia - Moscow

Spassimir Tonkov (ed.) 2003 Holocene vegetation history of the Central Rhodopes Mountains ... Palaeoecology 245 Aspects of Palynology and Festschrift in honour of Elissaveta Bozilova, pp. 245-255

Late Holocene vegetation history of the Central Rhodopes Mountains, Southern Bulgaria Maria Lazarova Institute of Botany, Bulgarian Academy of Sciences, Acad G. Bonchev str., blok 23, 1113 Sofia, Bulgaria. E-mail: [email protected]

ABSTRACT A reconstruction of the vegetation history and forest dynamics during the Late Holocene is discussed on the basis of palynological data obtained from a peat bog in the Central Rhodopes Mountains (Mugla). The pollen diagram covers a period of well-developed coniferous forests dominated by Pinus and Picea. Clear traces of anthropogenic impact are also recorded. KEY WORDS: Late Holocene – Pollen analysis – Vegetation history – Human impact – Central Rhodopes Mountains – Bulgaria

INTRODUCTION The recent distribution of the vast coniferous belt in the Central Rhodopes Mountains is a result of long-lasting dynamic changes caused by the complex interaction of ecological factors, migration processes, competitive interrelations between different tree species and by the active anthropogenic pressure during the last millennia as well. Possibilities for tracing of these changes in a retrospective plan are offered by the palynological investigations. During the last decade the stuides on the vegetation development in the Rhodopes Mountains were enriched by new data derived from the analyses of lateglacial and Holocene sequencies. These investigations were concentrated mainly in the region of Dospat, Western Rhodopes Mountains (Bozilova et al. 1989; Panovska et al. 1990; Huttunen et al. 1992; Panovska and Bozilova 1994; Filipovitch 1995; Bozilova et al. 2000; Filipovitch and Lazarova 2001, 2002). Until recently, information on the Holocene vegetation history in the Central Rhodopes Mountains was lacking. This article presents the first palynological data from the investigation of a peat bog in the region of Mugla. The pollen profile analyzed spans the last c. 2500 years of vegetation history and human impact.

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THE STUDY AREA Geomorphology and climate The relief of the Rhodopes Mountains with its characteristic morphostructure was shaped at the beginning of the Quaternary. The Central Rhodopes Mountains, especially the part between the rivers Vucha and Chepelarska, has an independent geomorphological pattern, distinguished by the clearly expressed uneven relief, higher displacements and typical valleys, allowing the penetration of the mediterranean climatic influence (Velkov et al. 1998). The climate of the investigated region could be defined as a montane version of the transitionalcontinental climatic area (Tishkov 1982). Above 1000 m the average January temperature is between -2ºC and -3ºC. The average July temperature is between 14.5ºC and 16.5ºC and slightly decreases above 1500 m. The greatest share of the precipitaion in winter time is snow. Recent vegetation This part of the Rhodopes Mountains falls within the Chernatish geobotanical region that is located between the Vucha river on one side and Arda river and Zalti Dyal on the other. The spruce forests are prevaling and they form the largest monodominant communities in Bulgaria. At some places are found associations dominated by Picea abies and Pinus sylvestris as a subdominant. The pine forests are also quite common but mostly fragmentally dispersed. On basic rock in xerophilous habitats are growing communities of Pinus nigra. Forests of Abies alba are more rarely found at some places mixed with Abies alba ssp. borisii-regis. In the eastern and partly in the northern areas of the region are found large massives of Fagus sylvatica. Vast areas in the northwestern part are occupied by Quercus dalechampii. Deciduous mixed forests composed of Fagus sylvatica, Carpinus betulus, Quercus daleschampii, with admixture of Ostrya carpinifolia, Fraxinus excelsior and Fraxinus ornus are quite common in the deep ravines (Bondev 1997). The study site A Sphagnum peat bog located within a spruce forest in the vicinity of the village Mugla (41º41' N, 24º 30' E, 1350 m a.s.l.) was selected for investigation (Fig. 1). The core for pollen analysis Mugla-2 (235 cm deep) was taken from the peripheral part of the peat bog. The bog vegetation itself and around the coring place is composed of different species of Sphagnum, Carex, Juncus, Eriophorum, Trifolium, Rumex, Geranium, Rhinanthus, Valeriana, Carduus, Orchis, Galium, Potentilla, Geum, Poaceae, Apiaceae, Ranunculaceae, etc.

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Fig. 1. Map of the study area and the location of sites mentioned in text: S Core Mugla-2; Sluncheva Polyana (Filipovitch 1995); Kupena (Bozilova et al. 1989; Huttunen et al. 1992); U Rhodopi (Athanasiadis et al. 1993; Gerasimidis and Athanasiadis 1995).

MATERIALS AND METHODS Pollen analysis The samples for pollen analysis were taken at every 10 cm and prepared according to the standard procedure (Faegri and Iversen 1989). The results of the analysis are presented on a percentage pollen diagram (Fig. 2). Pollen taxa with low values are not shown. The basic pollen sum is AP+NAP=100%, excluding pollen of Cyperaceae and spores of local origin. The percentage calculations and plotting of the diagram were done with the computer programs Tilia and Tilia-graph (Grimm 1991). Radiocarbon dating One sample collected at depth 170-175 cm was submitted for radiocarbon measurement at the Leibniz Laboratory for Radiometric Dating and Stable Isotope Research, Kiel, Germany. The result is 1670±60 BP (cal. 245–535 AD) (Lab. No KI-4843).

Fig. 2. Percentage pollen diagram Mugla-2.

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Fig. 2. Continued.

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RESULTS Pollen diagram A total of 116 pollen taxa were determined - 29 from the group of AP (arboreal pollen), 74 from the group of NAP (non-arboreal pollen), and 13 taxa of local origin (L) including pollen of Cyperaceae, hydrophytes and spores of mosses and pteridophytes. Four pollen assemblages zones (Mu-1…Mu-4) were distinguished reflecting successsive stages in vegetation development: PAZ Mu-1 (235-170 cm). AP is present with 40-54%. The dominant pollen types are Pinus diploxylon-type 5.3-15.2% (max. 24.8%) and Picea 5.1-15.3%. Pollen of Abies 1-2.7%, Betula 1.5% and Fagus up to 9.2% is registered in all samples. The presence of Pinus peuce is sporadic. The participation of Quercus, Carpinus betulus, Corylus and Tilia pollen is 3.2%, 5.5%, 6.6% and 2.4%, respectively. The rest of arboreal taxa (Ulmus, Acer, Fraxinus, Carpinus orientalis/Ostrya-type) are found with minimal values. The presence of Poaceae pollen is considerably high with 13-24.3%. Numerous herb pollen types are also determined: Achillea/ Aster-type 5.8%, Taraxacum-type 7.1%, Cirsium/Carduus-type 2.2%, Rumex 1.9%, Artemisia 1.7%, Brassicaceae 2.3%, Apiaceae 1.4%, etc. Spores from Polypodiaceae up to 36% and pollen from Cyperaceae with 4.8% are also recorded. PAZ Mu-2 (170-115 cm). AP curve attains maximal values of 54-79%. Pollen of Picea reaches 17.4% while Pinus diploxylon-type fluctuates between 19% and 32%. The pollen frequencies of Abies, Betula, Quercus and Carpinus betulus remain without significant changes. At the transition to the next zone Fagus rises to 17.7%. A slight decrease to 3.7% is observed for Corylus pollen. The pollen curve of Poaceae decreases from 18.7% to 4.3%. The diversity and the quantitative participation of the herb taxa are similar as in the preceding zone. Spores from Polypodiaceae up to 11.4% and a peak for the pollen curve of Cyperaceae up to 30% are registered. PAZ Mu-3 (115-60 cm). AP curve decreases from 73% to 30% mainly on the account of Pinus diploxylon-type 9.8% and Picea 3.3%. On the other hand, maximal values are registered for Pinus peuce 6%, Abies 3.4%, and Fagus 27.3%. A sharp decrease in the participation of all coniferous taxa at level 70 cm is observed. Minor changes are recorded for the participation of pollen from Quercus, Carpinus betulus, Tilia and Corylus. Pollen from Juglans with 1.6% is also found. The pollen curve of Poaceae reaches an absolute maximum of 61%. Pollen from Triticum/Avena-type and Secale is also determined. Other herb pollen types as Achillea/ Aster-type 5%, Taraxacum-type 3.4%, Rumex, Plantago lanceolata, Artemisia, Brassicaceae etc., are present in this zone. PAZ Mu-4 (60-0 cm). AP curve reaches again high values of 54-70%. An increase in the participation of Pinus diploxylon-type and Picea with 36% and 16% respectively, is recorded. Pollen from Abies is present with low frequencies. The pollen curve of Fagus decreases to 2-7% in comparison to the preceding zone. A slight rise for the pollen curves of Quercus up to 6.6% and of Carpinus betulus up to 3% is established. The participation of other arboreal taxa such as Tilia, Ulmus, Acer, Carpinus orientalis/Ostrya, Corylus, Alnus, Salix and Juglans

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decreases in this zone. The pollen curve of Poaceae rises from 8.5% to 13% (max. 28%). A higher number of herb pollen taxa with values above 1% is also established. DISCUSSION Vegetation history The results of the palynological investigation in the region of Mugla (Central Rhodopes Mountains) provide information on the characteristics of the vegetation dynamics during the Subatlantic chronozone. The pollen diagram reflects a period of well-developed coniferous forests and provides reliable evidence on the anthropogenic impact. On the basis of the pollen record and the radiocarbon dating, it is suggested, that the Sphagnum peat bogs in this region are relatively young in origin, formed during the Subatlantic. The reconstruction of the past vegetation reveals a vast distribution of coniferous forests dominated by Pinus and Picea, and corresponds to the last phase of the vegetation palaeosuccession in the Western Rhodopes Mountains (Bozilova et al. 1989, 2000; Huttunen et al. 1992; Panovska and Bozilova 1994; Filipovitch 1995; Filipovitch and Lazarova 2001, 2002), and in the montane area of Northern Greece (Athanasiadis et al. 1993; Gerasimidis and Athanasiadis 1995). The lowermost part of the diagram (PAZ Mu-1) indicates that the coniferous forests in the study have already shaped the upper timber line. The percentage values for both Pinus diploxylon-type and Picea are quite similar. The over-production and more effective dispersal of Pinus pollen, compared to the lower production of Picea, are well-known from the literature (Andersen 1970, 1974; Faegri and Iversen 1989) and should be taken into account when discussing the composition of the mixed coniferous forests. Our results confirm previous data from analysis of surface moss samples reported from the Stara Planina Mountains (Balkan Range) (Filipovitch and Lazarova 1997) and from the Rhodopes Mountains (Filipovitch and Lazarova 1999). The percentage participation of Picea in the pollen spectra is higher, compared to the rest of the tree constituents, if taken separately. In this case only Pinus diploxylon-type manifests higher values but below 25%. In our situation the ratio between Pinus and Picea pollen reveals the distribution of spruce forests with participation of Pinus. As admixture in these forests were also found Abies and single trees of Pinus peuce. Below the coniferous forests were distributed communities of Fagus, Carpinus betulus and Abies, while at lower altitudes the mountain slopes were covered by mixed oak forests dominated by different Quercus species with some Tilia and Ulmus. In these forests were also growing Acer, Fraxinus excelsior and shrubs as Corylus, Cornus, Viburnum and Euonymus. In the river valleys and in moister habitats were found stands of Alnus and Salix. The identification of pollen from Carpinus orientalis/Ostrya-type is assigned to the presence of both Carpinus orientalis and Ostrya carpinifolia, tree species that nowadays are distributed in this region.

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The vegetation of the Sphagnum peat bogs and around them was composed of various Poaceae, Cyperaceae, Ranunculaceae, Apiaceae, Brassicaceae species. The find of pollen from Plantago lanceolata, Artemisia, Rumex, Achillea/Aster-type, Cirsium/Carduus-type, Taraxacum, Urtica testifies to the human presence in the mountain. These pollen types are regarded as anthropogenic indicators for ruderal herb communities (Behre 1981). Cereal pollen of Triticum/Avena, Secale and Hordeum was also found in the lowermost samples. For Bulgaria it should be taken into consideration the presence of wild-growing grass species as Triticum beoticum, Secale montanum ssp. rhodopaeum, species from Agropyrum and Hordeum. However, this does not exclude the possibility for agricultural activities in the past on suitable areas in the higher parts of the mountain. The end of PAZ Mu-1 (170-175 cm) is dated at 1670±60 BP (cal. 245–535 AD) and marks the beginning of important changes in the vegetation cover. In the next phase of vegetation development (PAZ Mu-2) a quick enlargement of the forests is observed primarily caused by Pinus sylvestris and to less extent by Pinus nigra. Parallel to that, the areas occupied by Picea also reached their maximal distribution. The present day coniferous belt in the Central Rhodopes Mountains was shaped c. 2000 BP, outlining the upper tree limit composed of pine, spruce and mixed pine-spruce forests In this belt Abies and Pinus peuce were seldomly present as admixture. In the nearest palynological sites studied from the Western Rhodopes Mountains the quick expansion of Pinus was dated at 1850±100 BP (Sluncheva Polyana, Filipovitch 1995) and at 2070±100 BP (KupenaII, Hutunen et al. 1992). Since the beginning of the Subatlantic optimal conditions have already existed for the expansion of Fagus. Gradually, this tree gained a dominant position in the Abies-Carpinus communities, replacing them at many areas and forming a beech belt (Filipovitch and Lazarova 2001). In the Kupena area the increase of Fagus was also dated at 2070±100 BP (Hutunen et al. 1992). The expansion of Fagus in Subatlantic was documented in the pollen diagrams from the montane part of Northern Greece, the Rhodopes Mountains included (Athanasiadis et al. 1993; Gerasimidis and Athanasiadis 1995). The reasons for this increase of Fagus were most probably rather complex, including climate change and human interference as well. For the lower parts of the mountain no essential changes in the composition of the mixed deciduous forests were determined. The participation of Quercus, Ulmus and Tilia in these forests remained almost the same. The sharp decrease in the participation of the tree species (PAZ Mu-3) was a result of the high reduction of the communities of Pinus and Picea. At the beginning of the zone the beech forests reached their maximal development. It is quite possible that the increase in the percentage values of Fagus was partially caused by the lack of a dense forest filter. Similar conclusions are probably valid also for the increase of Corylus in comparison to the preceding zone, or hazel has invaded areas previuosly occupied by conifers. The regular presence of Juglans pollen in this zone suggests that this tree was cultivated widely by Man since the Iron Age and Roman time. The sharp decline of all tree species up to 30% (depth 70 cm) and the synchronous increase of Poaceae (up to 61%) were probably

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caused by a vast-scale deforestation, resulting in the enlargement of new areas suitable for pastures and agriculture. The final stage of the vegetation development (PAZ Mu-4) is related to the formation of recent plant communities in the Central Rhodopes Mountains. The coniferous PinusPicea forests, dominated by spruce, regained their wider distribution. The participation of Pinus peuce in these forests was restricted again but the same tendency was also observed for Fagus, most probably explained by an increase in human interference or the presence of a denser coniferous filter. Human impact The present investigation provides a possibility to trace the human impact on the vegetation in the study area since the beginning of the Subatlantic. The economic activities of the local population, inhabiting the Central Rhodopes Mountains, were rather diverse. The forests have been subjected to an intensive exploitation, cattle-breeding has been quite common, and even agriculture was practised on suitable areas. Timber was also used for the development of metallurgy as copper mining has played an essential role in the life of the local people (Velkov 1979). The increase in area of high mountain-pasture land was also achieved by burning the forests as proved by the find of different in size charcoal particles and low arboreal pollen values at depth of 70 cm. The long-lasting exploitation of the forests has led to significant changes in the natural vegetation and hence in the composition of the pollen spectra. The human induced changes in the forest vegetation have affected mainly the higher parts of the mountain occupied by the coniferous and beech vegetation belts. These changes at lower altitudes, where mixed oak forests were distributed, were of less importance. The general trend towards a decrease of arboreal pollen and the rise of herb pollen in the upper levels of the diagram, including the anthropogenic pollen indicators as Plantago lanceolata, Plantago media/major, Artemisia, Chenopodiaceae, Rumex, Achillea/Aster-type, Cirsium/Carduustype, Taraxacum, Urtica etc., could be commented as a result of the increasing human activity. This activity during the Iron Age and Roman time has contributed to significant changes in the forest composition thus rising the role of the anthropogenic factor in the formation of the recent plant communities. The frequent fluctuations of the total AP curve are accompanied by the presence of cereal pollen from Triticum/Avena-type and Secale. The find of pollen from Secale gives ground to suppose that agriculture was already developed in the region and the cultivation of cereals has been significantly facilitated by the introduction of iron tools. In conclusion, this first palynological investigation on the vegetation history in the Central Rhodopes Mountains dating back to the beginning of Subatlantic time, outlines the future trends in palaeoecological research in this interesting montane region, aiming at extending our knowledge on the complex character of the postglacial vegetation succession.

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ACKNOWLEDGEMENTS I am thankful to Prof. Elissaveta Bozilova, my teacher in palynology, for our fruitful joint work for many years. Thanks are due to Assoc. Prof. L. Filipovitch for the possibility to investigate this material and for her comments on the results. I am indebted to Dr. G. von Bülow and Dr. S. Conrad, Frankfurt, Germany, for the assistance to obtain the radiocarbon date. This paper is a contribution to Project B-701 supported by the National Science Fund, Ministry of Education and Science, Sofia. REFERENCES Andersen STh (1970) The relative pollen productivity and representation of North Europaean trees and correction of tree pollen spectra. Danm Geol Unders, Ser II: 96-99. Andersen STh (1974) Wind conditions and pollen deposition in a mixed deciduous forest.-II. Seasonal and annual pollen deposition. 1967-1972. Grana 14: 64-77. Athanasiadis N, Gerasimidis A, Eleftheriadou E, Theodoropoulos K (1993) Zur postglazialen Vegetationsentwicklung des Rhodopi-Gebirges (Elatia Dramas-Grichenland). Diss Bot 196: 427-437. Berhe K-E (1981) The interpretation of anthropogenic indicators in pollen diagrams. Pollen et Spores 23: 225-255. Bondev I (1997) Geobotanical regionalization. In: Yordanova M, Donchev D (eds) Geography of Bulgaria. Physical Geography: Vegetation, Academic Press, Sofia, pp 283-305 (In Bulgarian). Bozilova E, Panovska H, Tonkov S (1989) Pollenanalytical investigation in the Kupena National Reserve, West Rhodopes. Geographica Rhodopica 1: 186-190. Bozilova E, Atanassova J, Tonkov S, Panovska H (2000) Palynological investigation of peat bogs in the Western Rhodopes mountains (Southern Bulgaria). Geotechnical Scientific Issues, Thessaloniki 11, 3: 233-247. Faegri K, Iversen J (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester. Filipovitch L (1995) Palynological data on the formation of recent vegetation in Dospat Mountain in the Western Rhodopes. Phytologia Balcanica 1: 5-11. Filipovitch L, Lazarova M (1997) Surface pollen samples from the high-altitude slopes of Stara Planina (The Balkan Range). Phytologia Balcanica 3 (2-3): 41-52. Filipovitch L, Lazarova M (1999) Surface pollen samples from the coniferous belt of the Rhodopes Mountains. Phytologia Balcanica 5 (1): 15-27. Filipovitch L, Lazarova M (2001) Composition and trends in the development of vegetation in the Western Rhodopes (Southwest Bulgaria) during the Late Glacial and Holocene. Phytologia Balcanica 7 (2): 167-180. Filipovitch L, Lazarova M (2002) Late- and Post-Glacial vegetation dynamics in Western Rhodopes (Bulgaria) based on pollen analysis and radiocarbon dating. Compt rend Acad bulg Sci 55, 7: 55-60. Gerasimidis A, Athanasiadis N (1995) Woodland history of northern Greece from the mid Holocene to recent time based on evidence from peat pollen profiles. Veget Hist Archaeobot 4: 109-116. Grimm E (1991) Tilia and Tilia-graph. Illinois State Museum, Springfield, USA.

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Huttunen A, Huttunen R-L, Vasari Y, Panovska H, Bozilova E (1992) Late-Glacial and Holocene history of flora and vegetation in the Western Rhodopes Mountains, Bulgaria. Acta Bot Fenn 144: 63-80. Panovska H, Bozilova E (1994) Pollenanalytical investigation of three peat bogs in Western Rhodopes Mountains (Southern Bulgaria). Ann Sofia Univ, Fac Biol 85, 2: 69-85. Tishkov H (1982) Climatic division of Bulgaria. In: Galabov Z (ed) Geography of Bulgaria. Physical Geography 1. Bulg Acad Sci, Sofia, pp 240-247 (In Bulgarian). Velkov D, Vaptsarov I, Alexandrov A (1998) Relief as a factor of formation of the coniferous vegetation in the Rhodopes. In: Proceed Scient Papers Jubilee Sci Conf, Sofia I: 36-41 (In Bulgarian). Velkov V (1979) History of Bulgaria. Vol 1. Bulg Acad Sci, Sofia (In Bulgarian).

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© PENSOFT Publishers The new pollen Sofia - Moscow

Spassimir Tonkov (ed.) 2003 core Lake Durankulak-3: a contribution to the vegetation history ... Palaeoecology 257 Aspects of Palynology and Festschrift in honour of Elissaveta Bozilova, pp. 257-268

The new pollen core Lake Durankulak-3: a contribution to the vegetation history and human impact in Northeastern Bulgaria Elena Marinova Laboratory of Palynology, Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria E-mail: [email protected]

ABSTRACT Pollen analysis was conducted on a 340 cm core from Lake Durankulak, NE Bulgaria, supported with 5 AMS dates. The sediments were retrieved from the area between the western lake shore and the Large island – both places of human occupation since the Late Neolithic (5400–5300 cal. BC). According to the AMS dates the accumulation of sediments rich in pollen started at the transitional period between the Eneolithic and the Early Bronze Age (3800–3350 cal. BC). By that time open xerothermic vegetation with patches of steppe elements had dominated the landscape around the lake. The subsequent increase in arboreal pollen corresponds to the Early Bronze Age (2919–2392 cal. BC) together with the first maximum of the anthropogenic pollen indicators. The next period of pronounced human influence documented in the pollen record is related to the Late Bronze Age and the Antiquity (2000–600 cal. BC). The modern period is indicated by the appearance of Zea mays pollen in the uppermost samples. The new palynological information is compared with previous studies from this area. KEY WORDS: Pollen analysis – Human impact – Bronze Age/Iron Age – Lake Durankulak – NE Bulgaria

INTRODUCTION The vegetation history of the Black Sea coastal area in Northeastern Bulgaria has been intensively studied during the last two decades. Pollen diagrams covering the last 8000 years were published from the following freshwater basins: Lake Durankulak (Bozilova and Tonkov 1985, 1998), Lake Shabla-Ezeretz (Filipova 1985) and Lake Varna (Bozilova and Beug 1994). These diagrams generally demonstrated a long period of uniformity in forest composition for the greater part of the Holocene interrupted by distinct phases of

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human activity (Bozilova and Beug 1994). In addition, the palynological studies on marine sediments off the coast revealed that the main stages in forest development that followed the lateglacial steppe period were completed in the Early Holocene (Shopov et al. 1992; Atanassova 1995; Bozilova et al. 1997, etc.). In the inland of Northeastern Bulgaria, Lake Srebarna area, xerothermic oak forests were developed ca. 6000 BP and their degradation started with the Bronze Age human occupation (Lazarova and Bozilova 2001). Previous to the present, two pollen cores were already analysed from Lake Durankulak (Bozilova and Tonkov 1985, 1998). There are many reasons which make this lake an interesting site for palynological research. Its location allows to trace in detail the environmental changes in a sensitive area that has archived the characteristics of the transformation steppe/forest. The archaeological evidence of human occupation near the lake dates back to the Neolithic (Todorova 1985; Todorova and Vaisov 1989; Dimov 1990). Valuable palynological information related to the millennial anthropogenic impact on the surrounding environment is also available (Bozilova and Tonkov 1990, 2002). The new pollen core Durankulak-3 was analyzed for plant macrofossil and pollen content. The sediments studied were retrieved close to the prehistoric site. In the present paper the main results of pollen analysis are discussed in attempt to throw additional light on the vegetation history and the human impact particularly during the Bronze and Iron Ages. This new palynological information is compared with the previous studies and the available archaeological data as well. THE STUDY AREA Lake Durankulak is situated at the Black Sea coast in Northeastern Bulgaria (Fig.1). It is separated from the sea with a 200-300 m wide sand dune. The lake is about 3 km long, the deepest areas are about 3.8 m. The water is slightly brackish with a salinity of 2‰-4‰ and meso- to eutrophic. There are two islands. The lake lies in two Miocene limestone depressions of Sarmatian age. The lake originates from an estuary that was closed in the Late Pleistocene – Early Holocene (Popov and Mishev 1974). The climate of the area is determined by the strong continental influence and the nearness of the sea. The prevailing winds are north-eastern and the annual precipitation is 450-500 mm with a maximum in June and a minimum in February. The mean January temperature is around 0°C while inland dropping to -2°C. The most widespread soils are the chernozems. Several vegetation types are found in the surroundings of the lake: xerothermic foreststeppe and steppe, psammophyte and halophyte vegetation on the sand dunes and the shore, fragments of flooded forests along the rivers, hygrophilous and water vegetation. A profound description of the main plant communities was given in an earlier publication (Bozilova and Tonkov 1998). The reed formation in the peripheral parts of the lake is dominated by Phragmites australis, Typha latifolia, T. angustifolia and Schoenoplectus lacustris. The hygrophilous vegetation is represented by Alisma plantago-aquatica, Glyceria maxima, G. fluitans, Butomus umbellatus, Lythrum salicaria, Calystegia sepium (Kotchev et al. 1983).

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Fig. 1. Maps showing - A: The wider geographical context of the study are; B: Lake Durankulak and the coring site (marked with arrow) located between the western shore and the Large island.

MATERIAL AND METHODS Core and lithology The sediment core Durankulak-3, 340 cm long, was taken in September 1999 from the narrowest place between the western shore and the Large island with a square-rod piston sampler (Whrigt 1991) (Fig. 1). Advantageously, such coring device allows to retrieve coring segments 1 m in length thus to prevent the compression of the sediments, and to establish a continuous control over the coring process (Berglund 1986). The lithology of the core is shown on Table 1. In the interval 280-340 cm the core reached the loess underground. The transition from clay to clay-mud is recorded at level 250-240 cm and above it the pollen grains are well preserved. At depths 149 cm and 221 cm two shell layers are visible. The first layer is distinct, 2 cm thick, while the second one is seen as a shell enrichment. These two layers promote the comparison with the previous studies of Bozilova and Tonkov (1985, 1998) where such layers were also documented. Pollen analysis The samples for pollen analysis were taken at 5 cm intervals, and processed according to the standard method of Faegri and Iversen (1975). The clay admixture was removed with

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Table 1. Lithology of core Durankulak-3. Depth (cm)

Type

0 - 17 17 - 80 80 - 137 137 - 146 146 - 150 150 - 203 203 - 220 220 - 222 222 - 272 272 - 288 288 - 340

Grey-brown mud Black-brown Phragmites peat Dark brown mud with thin sand layers Calcareous mud Shell layer Dark grey-brown mud Black-grey clay mud Shell enrichment Black-grey clay mud Loess rich in organic matter Loess

an ultrasonic sieve (10 µm). The pollen types were determined using the reference collections of the University of Bonn and Sofia University, Laboratory of Palynology, and the keys in Beug (1961), Faegri (1993), Moore et al. (1991). Up to 1000 pollen grains of terrestrial pollen were counted per sample. In the interval 215-240 cm about 700 pollen grains of terrestrial plants were counted. The pollen concentration below 240 cm was low and the majority of pollen grains were corroded. The pollen sum (PS) for percentage calculations was based on AP (arboreal pollen) + NAP (non-arboreal pollen). The results of pollen analysis were plotted with the help of Tilia and Tilia-graph 1.2 program (Grimm 1991) as a simplified percentage pollen diagram with selected taxa (Fig. 2). Three local pollen assemblage zones (LPAZ) were established by means of stratigraphical constrained cluster analysis. Radiocarbon dating Five samples from the lower part of the core were submitted for AMS dating. The radiocarbon dates were obtained in the Leibnitz Labor für Altersbestimmung und Isotopenforschung, University of Kiel, Germany (KIA 12339 to KIA 12343). The dates Table. 2. Results of radiocarbon measurements of core Durankulak-3. Lab. No

Depth (cm) Age BP

KIA 12339 KIA 12340 KIA 12341 KIA 12342 KIA 12343

170 172,5 180 182,5 187,5

σ range) Age cal. BC (±2σ

3904±29 2469-2292 3908±31 2471-2292 4198±30 2885-2843; 2815-2672; 2645-2644 4153±35 2880-2618; 2611-2596; 2593-2582 4191±33 2885-2835; 2819-2649; 2649-2630

Material dated partly charred wood charred wood partly charred wood wood, Gallium fruits partly charred wood, Medicago fruit

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261

have been calibrated using the program CALIB rev4.3 (Stuiver et al. 1998) (Table 2). The dating of terrestrial plant material with the accelerator method is more precise compared to the dating of bulk sediment or shells. This method was chosen to date this part of the diagram where the first anthropogenic indicators start to increase. RESULTS Three local pollen assemblage zones (LPAZ) were established in the pollen diagram (Fig. 2). Their pollen stratigraphy is briefly presented: LPAZ Dur 1 (240-183 cm; Asteraceae-Poaceae-Chenopodiaceae) In this zone NAP is prevailing with ca. 85%. The dominant group is Asteraceae with 35% (Cichorioideae, Asteroideae, Artemisia, Centaurea jacea–type, Anthemis/Achilea–type), followed by Chenopodiaceae (30 %) and Poaceae (25 %). Other pollen types of importance are Ephedra, Adonis, Linum, Stachys-type, Apiaceae, Fabaceae, etc. AP is present with low values (20 %). Pollen of Quercus (mostly Q. robur-type) reaches 5%. Pollen of Fraxinus excelsior-type, Alnus, Ulmus, Hedera, Humulus, Lonicera is well represented. The first anthropogenic indicators appear at the transition to the next zone. Two subzones Dur 1a and Dur 1b are recognized. In the first one the pollen grains are slightly corroded. Selective pollen preservation and low pollen concentration are observed. The participation of Chenopodiaceae pollen is almost equal to that of Asteraceae (ca. 35%). In the second subzone the following anthropogenic indicators are present: Cerealiatype, Triticum-type, Polygonum aviculare, Plantago lanceolata-type, Rumex. LPAZ Dur 2 (183 - 96,5 cm; Poaceae-Chenopodiaceae-Artemisia) In this zone AP reaches 40%. The presence of the anthropogenic indicators is noticeable. This zone is also divided into two subzones. The first subzone Dur 2a is dominated by Poaceae with up to 60 %. The following anthropogenic pollen indicators deserve attention: Plantago lanceolata, Plantago major/media, Rumex, Polygonum. In the second subzone Dur 2a the pollen frequencies of almost all arboreal taxa rise: Quercus (20 %), Carpinus betulus (up to 12 %), C. orientalis-type (7 %), Fagus (5 %), Ulmus (4 %), Corylus (3 %). At level 120-125 cm the first pollen grains of Juglans appear. LPAZ Dur 3 (96,5-10 cm; Poaceae-Quercus) In this zone pollen of Quercus (particularly Q. cerris-type) attains a maximum of 28 %. At level 50 cm the total AP pollen curve declines to 15% at the expense of Poaceae 50%, partly Chenopodiaceae (20 %), and Artemisia (15 %). Pollen of Centaurea cyanus appears at levels 75, 70 and 50 cm. In the uppermost two samples pollen of Zea mays is determined. Two subzones Dur 3a and Dur 3b are recognized. In the first subzone maximal values are recorded for the lianas Vitis, Humulus and Hedera. The curve of Cerealia-type reaches 0,8 %. In the second subzone the pollen curves of Asteroideae and Chenopodiaceae rise to 30% and 40 %, respectively. Pollen of Rhamnus/Paliurus-type is also found. An increase in the participation of several hygrophytes and hydrophytes (Cyperaceae, Typha, Potamogeton) is also observed.

e

± 3904+-40 ± 3908+-31 ± 4189+-30 ± 4153+-35 ± 4191+-35

Ag

250

225

200

175

150

125

100

75

Mud

20

10

10

10

Phragmites peat

20

10 10

10

10

10

Mud+sand

10 10

10 10

40

20

40

60

Calcareous mud

20

Fig. 2. Simplified diagram of the pollen core Durankulak-3.

1

4C

BP

50

25

) cm

e p yp is e pe ty -t s p i l ab y ar s a t- y -ty n o u t h n si s ul n ( ur ris el nu Ca ista y rob cer bet orie th ex or us/ d g p s s s s lo cus cus nu nu s ul ra dra ae AP us nu nu De ho uer uer arpiarpiaguilia lmusoryrl axiraxiitis ummedephe P/N oace t i A 0 L Q Q C C F T U C F F V H H E P

Simplified diagram

Core Durankulak-3

10 10

10

Shells

10

20

20

20

Clay mud

20

40

10 10

10

10

2

Total su

Analysis: E. Marino

E xaggeration: 20x

Dur 1a

Dur 1b

Dur 2a

Dur 2b

Dur 3a

Dur 3b

ia re t a e d la a /m l u o ic e r e e e av nc ajo pe y p pe ac ea ae la m m di ty -t -ty s ia e d u i o i s n id ia m go go io op al eu um ma mi ro or go ex ta ta en re ord ritic ea rte ste ly um lan lanZones ch e i h o C H T Z A A C C P R P P CO ae

262 Elena Marinova

BP

) m (c

250

200

150

100

50

10

Clay

Detritus

20

Shells

20 10 10 10 10 10 10 10 10 10 10

40

60

Gyttia

20

40

20

20

Calc. mud+sand

10 10 10

e

80

20

40 10 10 10 10 10

Exaggeration: 10x

Analysis: Bozilova and To

20

o nv a e co an li le ea h id um kia o l u Ac io on rdy tag gon r/ o r g e e ly ld an ly m t ch As Ci Po Bi Pl Po Ru

Clay+sand

60

ea ac di

40

-t m sia po ia al icumdeu mi no e e e r r t t i Ce Tr Ho Ar Ch

e yp

Fig. 3. Simplified diagram of the pollen core Durankulak-2 (Bozilova and Tonkov 1998).

Phragmites peat

600

550

± 5300+-60 500

450

400

20

pe pe is is or al ty ty s ab lsi us rn is- tulu ient e u r n c n r P h e x or y rob s ce s be s or Ca pt s us s NA s/ a u u u og cus u ae u / l l De n n u r c i i s s in in l o er ce P er arp arp gu lia lmu ax ax ory tis umuede h a t A u u 0 Li Q Q C C Fa Ti U Fr Fr C Vi H H Po

300 ± 4020+-60 350 ± 4090+-60

± 2290+-50

C 14

e Ag

Simplified diagram

Core Durankulak-2 The new pollen core Lake Durankulak-3: a contribution to the vegetation history ...

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Elena Marinova

DISCUSSION Vegetation development and anthropogenic influence The human occupation in the area of Lake Durankulak had started during the Late Neolithic (5400–5300 cal. BC). A Late Neolithic settlement and an Eneolithic and Bronze Age necropolis were discovered on the western shore of the lake. On the Large island a complex archaeological site dating back to the Early Eneolithic was also excavated. It comprises cultural layers from the Eneolithic, Late Bronze Age and Medieval (Protobulgarian) settlements, and a Thracian sanctuary (Dimov 1990; Bojadziev 1992). The location of the new core Durankulak-3 close to both archaeological sites provides excellent possibilities for correlation of the palynological and archaeological data. An important prerequisite for such comparison is the series of radiocarbon dates that falls within the time interval 4191–3904 BP (2885–2292 cal. BC), and is related to the Bronze Age in conformity with the radiocarbon chronology for the bulgarian prehistory (Görsdorf and Bojadziev 1997). The dates indicate that an enlargement of the lake has probably taken place after the Eneolithic period. Another hint for this suggestion is the Eneolithic burial place where some of the graves today are under the water surface. According to the AMS dates the transitional period between the Eneolithic and the Bronze Age corresponds to LPAZ Dur 1. In this part of the diagram all tree taxa are present with low frequences (AP~20%). Most likely, the source area for arboreal pollen has been the stands of trees distributed along the rivers running into the lake. These patches of woody vegetation were composed of oaks (Quercus) with some Ulmus, Tilia, Fraxinus, Alnus, and lianas such as Humulus and Hedera. The presence of Pinus, Picea and Abies pollen in the fossil record originates from long distant transport. The xerothermic herbaceous vegetation with some steppe elements from Poaceae, Artemisia, Asteraceae, Chenopodiaceae, Adonis and Apiaceae, with groups of Ephedra among them, has dominated the landscape around the lake. At the beginning of this zone, which corresponds to the transition between the Eneolithic and Bronze Age, there are almost no anthropogenic indicators, apart from a weak signal of Cerealia-type, Hordeum-type, Plantago lanceolata und Rumex pollen. According to the archaeological evidence this transitional period was connected with a decline of the human occupation and invasions of steppe nomads (Todorova 1989). Considering the previous intensive human occupation of the Hamangia und Varna culture during the Eneolithic and its duration for more than 700 years (Bojadziev 1992), it seems that the expansion of the steppe elements was favoured by the increasing drought in the period 4000–3500 BP (Bozilova and Filipova 1986) after the abandonment of the arable land by the local population. Similar situation with drier conditions was also established for the period 4200–3700 BP in the Northern Black Sea area, in the south of Ukraine and Russia, along the Dniepr and Don rivers (Kremenetzki et al. 1999). In subzone Dur 1b the curves of the anthropogenic indicators start to rise, with an increase of the secondary anthropogenic indicators, particularly of Plantago lanceolata up to 4%. This curve shows that some pasture activities took place in the area. At the transition

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to the next zone an increase of the primary anthropogenic indicators (Cerealia-type, Triticumtype, Hordeum-type) is noticeable. In this subzone, parallel to the intensification of the anthropogenic impact, almost all tree pollen curves decrease, pointing to a decline in the distribution of the local forests. For this subzone two 14C dates were obtained (2885–2582 cal. BC) and they correspond to the Early Bronze Age (Table 2.). Charred plant macrofossils from the Bronze Age cultural layers of the Durankulak settlement were also studied (Popova 1995; Popova and Bozilova 1998). A wide spectrum of cultivated plants, especially cereals, was found: Triticum dicoccum, T. monococcum, T. spelta, T. aestivum, Panicum milliaceum, Hordeum vulgare, Vicia ervilia. Several charred stones of Prunus cf. avium, Sambucus nigra and Cornus mas were also recovered in the studied material. The next zone Dur 2 is characterised by an increase in arboreal pollen, mainly due to the rise of Quercus robur-type, Q. cerris-type, Carpinus betulus and C. orientalis-type. The forests in the surrounding area started to enlarge compared to the previous period. The anthropogenic indicators are well represented in the entire zone. The first subzone Dur 2a is dominated by Poaceae and Chenopodiaceae pollen. At level 170 cm a peak in the curve of the secondary anthropogenic indicators is registrated. It is formed predominantly on the increase of Plantago lanceolata. The available three 14C dates (2885–2292 cal. BC) correspond to the second part of the Early Bronze Age (Görsdorf and Bojadziev 1997) (Table 2.). Subzone Dur 2b is characterised by the highest AP values (up to 60%) for the entire profile. Most probably, the tree vegetation occupied larger areas around the rivers and the lake, represented by Carpinus betulus, C. orientalis and Fagus, together with Quercus robur and Q. cerris. In the middle of the zone (level 120 cm) a clear maximum of the anthropogenic indicators is registered. For the first time, pollen of Juglans is recorded in the diagram. The increase of the secondary anthropogenic indicators such as Plantago lanceolata, Polygonum aviculare, Rumex and Chelidonium could be connected with the Thracian settlement and sanctuary that were found on the Large island. According to the archaeological data, this period is related to 1200–1050 BC (Todorova 1985). The third zone Dur 3 is characterised by a slight decrease of arboreal pollen. Most of the tree pollen curves decline and only Quercus cerris- and partly Q. robur-type keep higher values reaching up 20%. It could be suggested that this situation represented “islands” of xerothermic oak woods, being regularly reduced by the local people, and replaced by xerothermic herb vegetation with steppe elements. A high proportion of AP is still recorded in subzone Dur 3a and at the transition to subzone Dur 3b it starts to decrease. Among the NAP taxa the highest values are established for Chenopodiaceae, Poaceae and partly to Artemisia and Asteroideae. The find of Zea mays pollen is a result of the cultivation of maize as a crop plant from the beginning of the 17th century onwards (Kitanov 1986) so that the uppermost part of the diagram could be assigned to the last 200-250 years.

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Comparison with previous studies As mentioned above, two pollen cores of Lake Durankulak were already studied. They originate from the same area between the western lake shore and the Large island. The core Durankulak-1 was taken 10-15 m in northeastern direction from the present core (Bozilova and Tonkov 1985) while the core Durankulak-2 was recovered 30 m in south-western direction (Bozilova and Tonkov 1998). The results from the first study were revised and improved by the authors. It is tempting and logical to compare the new results with the previous ones published in 1998. For this purpose, the pollen diagram Durankulak-3 is compared to the pollen diagram Durankulak-2 (Fig. 3). Comparing both diagrams, it should be born in mind that in the study of Bozilova and Tonkov (1998) the pollen sum was based on 250-270 terrestrial pollen grains. The lithology of both profiles shows the presence of calcareous mud with two shell layers. These layers can be used to some extent as a reference point to correlate both diagrams. The first zone D-1 of core Durankulak-2 is not present in core Durankulak-3. Certain similarities in the course of the pollen curves are observed between zone D-2, and zones Dur 1b and Dur 2a. In both diagrams maximal values of Cichorioideae and Asteroideae pollen are recorded. Above these maxima, peaks of Plantago lanceolata and P. coronopus appear and subsequently an increase of arboreal pollen is observed. The AMS dates of Durankulak-3 indicate that this part of the diagram could be related to the Early Bronze Age. In the publication of Bozilova and Tonkov (1998), the corresponding part of the diagram was assigned to the Eneolithic period. The shell layer was dated ca. 4090–4020 BP (2600–2500 cal. BC). In core Durankulak-3 radiocarbon dates of similar age were obtained for the sediments 40 cm below the shell layer. Probably, the differencies are connected with the dating methods applied. Above the shell layer in both cores an increase of AP is recorded, i.e. in zones Dur 2b and Dur 3a (core Durankulak-3) and in zones D-3 and D-4 (core Durankulak-2). Subzone Dur 3b has no analogue in the pollen diagram Durankulak-2. CONCLUSIONS 1. The new pollen record provides additional information on the vegetation changes and human impact in the area of the praehistoric site Durankulak. 2. The AMS dates reveal that the sediments started to accumulate during the transitional period between the Eneolithic and the Bronze Age. 3. The first maximum of the pollen anthropogenic indicators refers to the Early Bronze Age, while subsequent peaks are registered during the Late Bronze Age, Iron Age and Antiquity. The last maximum is probably connected with the Proto-bulgarian settlement that had existed during 9th-10th centuries.

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ACKNOWLEDGEMENTS I dedicate this paper to Prof. Elissaveta Bozilova who inspired me to start research in the field of Quaternary palaeoecology and had a great positive influence on my scientific career. I would like to thank Prof. Th. Litt who provided financial support to obtain the AMS dates. I am grateful to Prof. E. Bozilova, Prof. Th. Litt, Assoc. Prof. S. Tonkov and Prof. D. Peev for their invaluable help in the coring expedition to Lake Durankulak. This study was undertaken during my stay in the University of Bonn through a Ph. D. grant kindly provided by the Friedrich Naumann Fund, Germany. The comments and suggestions on an earlier version of the manuscript by Assoc. Prof. S. Tonkov are kindly acknowledged. The English of the text was checked by Dr. N. Kühl. REFERENCES Atanassova J (1995) Palynological data of three deep water cores from the western part of the Blak Sea. In: Bozilova E, Tonkov S (eds) Advances in Holocene Palaeoecology in Bulgaria. Pensoft Publ. Sofia-Moscow, pp 68-83. Berglund BE (ed.) 1986 Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley & Sons, Chichester. Beug HJ (1961) Leitfaden der Pollenbestimmung 1. Gustav Fischer Verlag, Stuttgart. Bojadziev J (1992) Chronology of the praehistoric cultures on the territory of Dobrudza. Dobrudza 9: 10-19 (in Bulgarian). Bozilova E, Beug HJ (1994) Studies on the vegetation history of Lake Varna region, northern Black Sea coastal area of Bulgaria. Veget Hist Archaeobot 3: 143-154. Bozilova E, Filipova M (1986) Palaeoecological Environment in Northeastern Black Sea Area during Neolithic, Eneolithic and Bronze Periods. Studia Praehistorica 8: 160-165. Bozilova E, Tonkov S (1985) Palaeoecological studies in Lake Durankulak. Ann Sofia Univ, Fac Biol 76, 2: 25-30. Bozilova E, Tonkov S (1990) The impact of main on the natural vegetation in Bulgaria from the Neolitic to the Middle Ages. In: Bottema S et al. (eds) Man’s Role in the Shaping of the Eastern Mediterranean Landscape. Balkema, Rotterdam, pp 327-332. Bozilova E, Tonkov S (1998) Towards the vegetation and settlement history of the southern Dobrudza coastal region, north-eastern Bulgaria: a pollen diagram from Lake Durankulak. Veget Hist Archeobot 7: 141-148. Bozilova E, Tonkov S (2002) Paleoecological evidence on the vegetation history and human occupation in the coastal area of Lake Durankulak, Northeastern Bulgaria. In: Todorova H (ed) Durankulak, Band II. Deutsches Archäologisches Institut-Berlin, Publ House Anubis. Sofia, pp 309-312. Bozilova E, Atanassova J, Filipova-Marinova (1997) Marinopalynological and archaeological evidence for the Lateglacial and Holocene vegetation in Eastern Bulgaria. Ann Sofia Univ, Fac Biol 89, 2: 69-81. Dimov T (1992) The Culture Hamangia in Dobrudza. Dobrudza 9: 20-35 (in Bulgarian).

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Faegri K (1993) Bestimmungsschlüssel für die nordwesteuropäische Pollenflora. Gustav Fischer Verlag, Jena. Faegri K, Iversen J (1989) Textbook of Pollen analysis. 4th ed. John Wiley and Sons, Chichester. Filipova M (1985) Palaeoecological investigation of lake Shabla-Ezeretz in North-eastern Bulgaria. Ecol Mediter 11 (1): 147-158. Görsdorf J, Bojadziev J (1997) Zur absoluten Chronologie der bulgarischen Urgeschichte. Berliner C14 Datierungen von bulgarischen archäologischen Fundplätzen. Eurasia Antiqua 2: 105-173. Kitanov B (1986) The cultivated plants in Bulgaria. Nauka i Izkustvo, Sofia (in Bulgarian). Kotchev H, Kovatchev S, Uzunov J (1983) The biological characteristics of Lake Durankulak and some problems of its protection. Proceed Third Nation Bot Conf Sofia, pp 925-934 (in Bulgarian). Kremenetzki K, Chichagova O, Shishlina N (1999) Paleoecological evidence for Holocene vegetation, climate and land use change in the low Don basin and Kalmuk area, Southern Russia. Veget Hist Archaeobot 8: 233-246. Lazarova M, Bozilova E (2001) Studies on the Holocene history of vegetation in the region of lake Srebarna (Northeast Bulgaria).Veget Hist Archaeobot 10: 87-95. Moore PD, Webb JA, Collinson ME (1991) Pollen Analysis. Blackwell Science Publications, Oxford. Popov V, Mishev K (1974) The geomorphology of the Bulgarian Black Sea coast and shelf. Sofia (in Bulgarian). Popova Tz (1995) Plant remains from Bulgarian Prehistory (7000-2000 BC). In: Bailey D, Panajotov I (eds) Prehistory of Bulgaria. Monographs in World Archaeology 22 I: 193-207. Popova Tz, Bozilova E (1998) Palaeoecological and Palaeoethnobotanical Data for the Bronze Age in Bulgaria. In: Stefanovich M, Todorova H, Hauptman H (eds) In The Steps of James Harvey Gaul. Volume 1. The James Harvey Gaul Foundation, Sofia, pp 391-398. Shopov V, Bozilova E, Atanassova J (1992) Biostratigraphy and radiocarbon data of Upper Quaternary sediments from western part of Black Sea. Geologica Balcanica 22: 59-69 (in Bulgarian with English summary). Stuiver M, Reimer P, Bard E, Beck WJ, Burr GS, Hughen K, Kromer B, McCormac G, van der Plicht J, Spurk M (1998) INTCAL98 Radiocarbon Age Calibration, 24,000-0 cal BP. Radiocarbon 40, 3: 1041-1083. Todorova H (1985) Dobrudza during the praehistoric period. In: Fol A, Dimitrov S (eds) History of Dobrudza. Sofia, pp 23-61 (in Bulgarian). Todorova H (1989) Durankulak I. Bulg Akad Sci, Sofia (in Bulgarian). Todorova H, Vaisov I (1989) The Neolithic Epoch in Bulgaria. Nauka i Izkustvo, Sofia (in Bulgarian). Wright HE Jr (1991) Coring tips. J Paleolimn 6: 7-49.

© PENSOFT Publishers Sofia - Moscow

Spassimir Tonkov (ed.) 2003 Pollen morphology of the genus Ononis L. (Fabaceae) Bulgaria 269 Aspects ofinPalynology and Palaeoecology Festschrift in honour of Elissaveta Bozilova, pp. 269-282

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria Dolja Pavlova*, Siwert Nilsson† and Spassimir Tonkov Laboratory of Palynology, Department of Botany, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 15 Tsar Osvoboditel bd., 1000 Sofia, Bulgaria * E-mail: [email protected]

ABSTRACT The pollen morphology of the species Ononis adenotricha Boiss., O. pusilla L., O. arvensis L., O. spinosa L. ssp. antiquorum, O. repens L., O. reclinata L., distributed in Bulgaria was investigated with SEM and LO microscopy. The results show that the pollen grains are 3-zonocolporate of prolate and subprolate type. Differences are observed in the dimensions, the aperture shape and the outline of the pollen grains. The endopori and ectocolpi vary in shape and dimensions. The ectocolpi are straight and the endopori are large in size, circular or elliptical. The ornamentation is reticulate with differences in the size and shape of the lumina. Two pollen types could be distinguished: I type - polar diameter less than 25 µm, elliptic in equatorial view and triangular-obtuse in polar view, P/E 1.15 -1.33 (subprolate) (O. adenotricha, O. reclinata, O. pusilla); II type - polar diameter above 25 µm; elongated, rectangular-obtuse in equatorial view and circular in polar view, P/E 1.38-1.6 (prolate) (O. repens, O. arvensis, O. spinosa ssp. antiquorum). KEY WORDS: Pollen morphology – Fabaceae – Ononis – Bulgaria.

INTRODUCTION The genus Ononis L. is a part of the tribe Trifolieae in the sense adopted by Polhill and Raven (1981). The tribe Trifolieae includes the genera which have the closest relationship to Ononis in various morphological characters. The evolutionary relationships are better expressed, therefore, by uniting Ononis with the Trifolieae than by retaining the genus in a monogeneric tribe (Polhill and Raven 1981). The geographic distribution of the genera of Trifolieae greatly varies (Meusel et al. 1965). In general, the Mediterranean region may be considered as the main center of diversity of the tribe whereas the species with the most primitive characters in Trigonella and Medicago occur mainly in Central Asia. Genus Ononis includes about 75 species with a center of diversity in the West Mediterranean (Polhill and Raven 1981).

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Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

In the Bulgarian flora there are six species - Ononis adenotricha Boiss., O. pusilla L., O. arvensis L., O. spinosa L. ssp. antiquorum, O. repens L., O. reclinata L. (Kuzmanov 1976; Kozuharov 1992). The pollen morphology of Ononis is still incompletely investigated. Information is available in some regional pollen morphological studies and in several general surveys of the family Fabaceae (Planchais 1964; Erdtman 1966; Kupriyanova and Aleshina 1972; Tarnavschi et al. 1990). Pollen of both genera Ononis and Melilotus is ascribed to one pollen type (Ononis-type) by Faegri and Iversen (1989), and Moore et al. (1991). The main reason for this statement are the 3-colporate pollen grains and the reticulate ornamentation of the exine. This description of the pollen morphology is supported by Guinet (1981), Ferguson (1984), Ferguson and Skvarla (1981), Polhill and Raven (1981), Guinet and Ferguson (1989), Moore et al. (1991), Reille (1992), Chester and Raine (2001). The aim of the present paper was to study the pollen morphology of Ononis species distributed in Bulgaria and, by comparing the results with data previously published, to provide new information on the taxonomy and evolutionary relationships within this group. MATERIAL AND METHODS The pollen material was collected from natural populations of the taxa concerned in Bulgaria. Voucher specimens are deposited in the Herbaria of Sofia University (SO) and Institute of Botany (SOM) (Table 1). Pollen grains for LO examination were acetolysed by the standard procedure (Erdtman 1960). The slides were prepared by mounting the pollen in glycerol jelly. Seven characters were measured at a magnification of × 1280 - P (polar diameter), E (equatorial diameter), Lc (colpus length), M (mesocolpium), A (apocolpium), Sp (porus width), Lp (porus length), and the P/E ratio. Fifty measurements of each character were made and the mean value and ranges are shown on Table 1. For scanning electron microscopy (SEM) pollen grains were coated as dry specimens. The microphotographs were obtained with SEM of the Electron Microscopy Laboratory, Swedish Museum of Natural History, Stockholm (Figs. 1-5). The percentage ratio for pollen fertility/sterility was reported on 5 different colours as all pollen grains (sometimes over 5000) on the microscope slide were counted for the populations of O. arvensis. The staining of the material was done after the method of Alexander (1969). The morphometrical measurements and the ratios P/E, Lc/Lp, P/Lc and E/M were used for the cluster analysis. The morphometrical data were clustered by the program Statistica 4.3 for Windows following the method of Chemeris and Androschuk (1982). The euclidean distances were used to graft the dendrograme and to show the relationships between the species on the basis of pollen morphological data (Fig. 6). The plant nomenclature follows Kozuharov (1992). The pollen terminology in general follows Faegri and Iversen (1975) and Punt et al. (1994).

16.8(18.56)20.8

20.0(22.0)23.2

5.6(7.2)8.0

24.0(27.4)28.0

Ononis arvensis L. Rila Mts., Eleshnitsa SO 99 785

6.4(7.1)8.8

25.28(27.9)30.02 14.22(17.39)18.96 20.54(23.16)26.86 3.95(6.47)7.9

17.6(19.4)21.6

Ononis repens L. Znepole region, Lobosh village SO 100 385

Type II

22.12(23.8)23.79 15.8(20.12)22.12 17.38(19.49)22.12 4.74(6.74)9.48

Ononis pusilla L. Struma valley SO 100 600

18.4(19.4)21.6

6.4(8.32)8.32

22.4(23.7)24.8

19.2(20.48)22.4

Ononis pusilla L. Thracian plain, Ognjanovo village SO 97 805

19.2(20.56)22.4

22.4(23.8)24.8

3.2(4.4)5.6

Lp

15.8(16.56)18.96 3.95(4.18)6.32

10.4(12.9)14.4

Lc

Ononis pusilla L. Strandza Mts. SO 96 846

12.8(13.2)14.4

E

18.96(19.9)22.12 12.64(15.32)15.8

14.4(16.3)19.2

P

Ononis reclinata L. Struma valley, Kulata village SOM 103 572

Type I Ononis adenotricha Boiss.Thracian plain, Ognjanovo village SO 97 804

Types and taxa

5.6(7.2)8.0

3.95(5.68)7.9

4.74(6.04)7.9

5.6(6.98)8.0

6.4(7.78)10.4

3.95(5.53)7.9

3.2(4.1)5.6

Sp

9.6(12.9)14.4

5.68(10.9)12.64

9.48(13.17)15.8

11.2(13.4)16.0

12.8(14.24)16.8

7.9(11.06)9.63

7.2(9.36)11.2

M

1.22

1.15

1.3

1.23

P/E

4.8(6.1)8.0

4.74(5.37)7.11

1.47

1.6

6.32(8.69)9.48 1.23

4,8(5.97)7.2

4.0(5.54)6.4

3.16(4.52)4.74

3.2(4.3)4.8

A

Table 1. Taxa examined for pollen types, with measurements (µm) of the mean and ranges for the polar (P) and equatorial (E) axes, colpus length (Lc), porus length (Lp) and width (Sp), mesocolpium (M) and apocolpium (A) and the shape index (P/E).

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria

271

A

P/E

20.8(23.1)25.5

18.96(21.42)23.7

16.0(17.4)19.2

Ononis spinosa L. ssp. 23.7(26.07)28.88 15.8(18.06)22.12 antiquorum (L.) Arcang. Black Sea coast, Baltchik village SO 100 567

Ononis spinosa L. ssp. 25.6(27.36)28.8 antiquorum (L.) Arcang. Black Sea coast, Tzarevo village SO 40 530

18.96(21.44)23.7

4.74(6.41)7.9

5.6(6.2)6.0

4.74(6.74)7.9

3.32(6.36)7.9

4.8(6.0)6.4

4.74(6.37)7.9

7.9(11.37)14.22

9.6(11.1)12.0

9.48(12.37)14.22

7.9(10.9)12.64

1.57

1.42

4.74(5.78)6.32 1.49

3.2(4.56)5.6

4.74(6.68)7.9

4.74(5.32)6.32 1.38

23.7(25.33)26.86 15.8(18.91)20.54 18.96(21.49)25.28 4.74(6.37)7.9

M

Ononis arvensis L. Black Sea coast, Kranevo village SO 101 418

Sp

4.74(6.74)7.9

Lp

23.7(25.38)26.86 15.8(18.33)18.96

Lc

Ononis arvensis L. Lozenska Mts. SO 101 419

E 4.77(6.39)7.94 9.74(11.82)13.51 3.97(5.16)6.35 1.42

P

Ononis arvensis L. 23.84(26.12)28.6 16.69(18.37)19.87 19.87(22.52)24.24 4.77(5.84)7.15 Rila Mts., Gjolechitsa SO 99 782

Types and taxa

Table 1. Continued.

272 Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria

273

RESULTS AND DISCUSSION The pollen grains of Ononis are 3-zonocolporate, prolate and subprolate. In the investigated populations of O. arvensis and O. spinosa ssp. antiquorum 5-colporate sterile pollen grains with short colpi, large elliptic pores and a reticulate ornamentation were also found. The ectocolpi are straight, shallow, narrowing at the poles. The colpus margin is uneven and the colpus membrane is covered by large granules. The endopori are large, circular or elliptical. The exine is of the same thickness throughout the pollen surface. The ornamentation is reticulate, the lumina different in shape and size. In equatorial view the pollen grains are elongated, elliptic to rectangular-obtuse, and in polar view they are circular or triangular-obtuse. Two pollen types can be distinguished on the base of pollen size, shape in polar and equatorial view, and P/E ratio. Type I (Figs. 1 and 2) Polar diameter less than 25 µm, outlines elliptic in equatorial view and triangular-obtuse in polar view, P/E 1.15-1.33 (subprolate). The pollen grains are small in size (O. adenotricha, O. reclinata), dimensions P × E = 14.424.8 × 12.64-22.12 µm. Ectocolpi straight, shallow, approximately 1.6 µm wide in the equatorial area, colpus membrane covered by sculptural elements of different sizes. Lc = 10.4-22.4 µm. Endopori circular Lp × Sp = 3.2-9.48 × 3.2-10.4 µm. Exine 0.8-1.2 µm thick in the mesocolpium. Ornamentation reticulate, except in the colpus area. Lumina isodiametric variable in size, some of the largest lumina are in the mesocolpium reaching 1.6 µm in size. The ornamentation is the same in the apocolpium and mesocolpium. The pollen grains of O. adenotricha, O. reclinata and O. pusilla belong to this type. The pollen grains of O. adenotricha and O. reclinata are quite similar, while those of O. pusilla show some differences in shape, size, aperture, length of equatorial and polar diameters. The pollen grains of O. pusilla (population from Strandza Mts.) are the largest measured for this pollen type. They show the maximal values for porus length and width within all taxa investigated. Type II (Figs. 3, 4 and 5) Polar diameter above 25 µm, outlines in equatorial view rectangular-obtuse and circular in polar view, P/E 1.38-1.6 (prolate). The pollen grains are elongated, of medium size, P × E = 23.7-30.02 × 14.22-20.8 µm. Ectocolpi long, shallow, colpus membrane covered by sculptural elements of varying size, colpus margin uneven. Lc = 18.96-26.86 µm. Endopori circular or elongated, Lp × Sp = 3.95-8.0 × 3.32-7.9 µm. Exine about 1.6 µm, with equal thickness. Ornamentation reticulate, except in the colpus area. The largest lumina are observed in the intercolpium. The ornamentation in the apocolpium and mesocolpium is of the same type. The pollen grains of O. repens, O. arvensis, O. spinosa ssp. antiquorum belong to this type. The taxa differ in their shape in equatorial view and the ratio P/E which is lower in O.

274

Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

A

D

B

E

C

F

Fig. 1. Pollen grains of Ononis adenotricha. A (LM) equatorial view and colpi. Scale bar = 4 µm; B (LM) polar view. Scale bar = 4 µm; C (LM) ornamentation in mesocolpium. Scale bar = 4 µm; D F (SEM) colpus, polar view and ornamentation. Scale bar = 1 µm.

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria

A

C

E

275

B

D

F

Fig. 2. Pollen grains of Ononis reclinata (A - D) and O. pusilla (E - F). A and B (LM) equatorial view, colpus and porus 1600. Scale bar = 4 µm; C (LM) equatorial view, 1280. Scale bar = 4 µm; D (SEM) ormanentation in apocolpium and mesocolpium. Scale bar = 10 µm; O. pusilla E - F (LM) equatorial view and porus 1600. Scale bar = 4 µm.

276

A

B

Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

D

E

F C

Fig. 3. Pollen grains of Ononis repens. A - C (LM) equatorial view, colpus and porus, ornamentation 1600 and 1280. Scale bar = 4 µm; D - E (SEM) equatorial view and outline, colpus and porus. Scale bar = 10 µm, F (SEM) ornamentation. Scale bar = 1 µm.

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria

A

277

C

D

B

E

Fig. 4. Pollen grains of Ononis arvensis. A - B (LM) porus and colpus, ornamentation in mesocolpium 1600. Scale bar = 4 µm; C - D (SEM) equatorial view, mesocolpium and apocolpium. Scale bars = 10 µm; E (SEM) ornamentation and porus area. Scale bar = 1 µm.

278

Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

A

D

B

E

C

F

Fig. 5. Pollen grains of Ononis spinosa ssp. antiquorum. A - C (LM) ornamentation, equatorial view, colpus and porus 1600. Scale bar = 4 µm; D - E (SEM) mesocolpium, colpus and porus. Scale bars = 10 µm; F (SEM) colpus membrane and ornamentation. Scale bar = 1 µm.

Pollen morphology of the genus Ononis L. (Fabaceae) in Bulgaria

279

Fig. 6. Cluster analysis.

arvensis. The lumina in O. spinosa ssp. antiquorum are the largest compared to all the taxa investigated. The check for pollen fertility/sterility in O. arvensis (two populations) shows that 73.6% of all pollen grains (population Eleshnitsa) and 94.4% (population Gjolechitsa) are sterile. The high incidence of pollen sterility suggests that vegetative reproduction is the dominant type, leading to the appearance of a great variety of forms. The pollen morphological data allow the following groups to be distinguished: 1. The pollen grains of O. adenotricha and O. reclinata are quite similar taking into consideration the values of P, E, Lc, Lp and the corresponding ratios. 2. The species O. arvensis, O. spinosa and O. repens are placed in a separate group with close values of the euclidian distances. This group demonstrates clear differences in respect of pollen morphology compared to the previous group, and this is also confirmed by the cluster analysis. 3. The species O. pusilla occupies an intermediate position between both groups. In fact, the pollen grains of this species possess a combination of characters, found in the two main groups. The analysis of the pollen morphology of the species investigated confirms the taxonomical scheme for the genus Ononis proposed by Sirjaev (1932). CONCLUSIONS The results from the present study show that the morphology of the pollen grains of the Bulgarian representatives of the genus Ononis is comparatively homogenous and confirms in broad lines the descriptions presented by Faegri and Iversen (1975) and Moore et al.

280

Dolja Pavlova, Siwert Nilsson† and Spassimir Tonkov

(1991). The pollen grains of the species from the group O. spinosa (Kuzmanov 1976; Kozuharov 1992) do not demonstrate clear features which could be used for taxonomic differentiation. The pollen-morphological measurements indicate that there is not always a correlation between pollen size and ploidy level, if we rely on the karyological data available (Bolkhovskikh et al. 1969; Morisset 1978; Goldblatt 1981; Goldblatt and Johnson 1991, 1994, 1996; Kuzmanov 1993; Pavlova and Tosheva, 2000). For example, the diploid species O. adenotricha, has the smallest size pollen grains of all species studied. In the same group are included the pollen grains of O. reclinata despite its higher ploidy (2n=60, 64) (Bolkhovskikh et al. 1969). On the other hand, the species O. pusilla (2n=30, 34) is in the same group. Tracing the pollen morphology of the genus Ononis, we could conclude that a clear difference exists between the annual and perennial species, which fully coincides with the results from the cluster analysis and the generic taxonomical scheme (Sirjaev 1932; Ball 1968). ACKNOWLEDGEMENTS It is our pleasure to dedicate this paper on the occasion of the jubilee anniversary of Prof. Elissaveta Bozilova in recognition of her substantial contribution to the development of the modern pollen-morphological studies in Bulgaria. We are indebted to H. Tinsley, Bristol, UK, who was so kind as to check the English of the text. This paper is a contribution to project №356/2001 supported by the Research Fund at Sofia University “St. Kl. Ohridski”. REFERENCES Alexander MP (1969) Differential staining of aborted and nonaborted pollen. Stain Techn 44 (3): 117-122. Ball PW (1968) Ononis L. In: Tutin TG et al. (eds) Flora Europaea 2, pp 148-150. Bolkhovskikh Z, Grif V, Matvejeva T, Zakharyeva O (1969) Chromosome numbers of flowering plants. Nauka, Leningrad. Chemeris ES, Androschuk AF (1982) The use of euclidean distances in karyotaxonomical analysis. Dokl AN Ukraina, Ser B 4: 73-74 (In Russian). Chester P, Raine J (2001) Pollen and spore keys for Quaternary deposits in the northern Pindos Mountains, Greece. Grana 4: 299-387. Erdtman G (1960) The acetolysis method. A revised description. Svensk Bot Tidskr 54: 561-564. Erdtman G (1966) Pollen Morphology and Plant Taxonomy. Angiosperms. Hafner Publishing Company, New York and London. Faegri K (1956) Palynological studies in NW European Papilionaceae. Botanical Museum, Bergen. Faegri K, Iversen J (1989) Textbook of pollen analysis. 4th ed. John Wiley & Sons, Chichester.

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Ferguson K (1984) Pollen morphology and biosystematics of the subfamily Papilionoideae (Leguminosae). In: Grant W (ed) Plant Biosystematics. Academic Press, Canada, pp 377-394. Ferguson K, Skvarla J (1981) The pollen morphology of the subfamily Papilionoideae (Leguminosae). In: Polhill R, Raven P (eds) Advances in Legume Systematics. Part 2, Royal Bot Gard Kew, pp 859-896. Goldblatt P (1981) Index to plant chromosome numbers for 1975-1978. Monogr Syst Bot, Missouri Bot Gard, 5. Goldblatt P, Johnson DE (1991) Index to plant chromosome numbers for 1988-1989. Monogr Syst Bot, Missouri Bot Gard, 40. Goldblatt P, Johnson, DE (1994) Index to plant chromosome numbers for 1990-1991. Monogr Syst Bot, Missouri Bot Gard, 51. Goldblatt P, Johnson DE (1996) Index to plant chromosome numbers for 1992-1993. Monogr Syst Bot, Missouri Bot Gard, 52. Guinet Ph (1981) Comparative account of pollen characters in the Leguminosae. In: Polhill R, Raven P (eds) Advances in Legume Systematics. Part 2, Royal Bot Gard Kew, pp 789-799. Guinet Ph, Ferguson K (1989) Structure, evolution, and biology of pollen in Leguminosae. In: Stirton C, Zarucchi J (eds) Advances in Legume Biology. Monogr Syst Bot, Missouri Bot Gard 29: 77-103. Kozuharov S (1992) Fabaceae. In: Kozuharov S (ed) A guide to higher plants in Bulgaria. Nauka i Izkustvo, Sofia, pp 382-441 (In Bulgarian). Kupriyanova L, Aleshina L (1972) Pollen and spores from the European part of USSR 1. Nauka, Moskva (In Russian). Kuzmanov B (1976) Ononis L. In: Jordanov D (ed) Flora NR Bulgaria. Bulg Acad Sci, Sofia, pp 259269 (In Bulgarian). Kuzmanov B (1993) Chromosome numbers of bulgarian angiosperms: An introduction to a chromosome atlas of the Bulgarian flora. Flora Mediter 3: 19-163. Meusel H, Jager E, Weinert E (1965) Vergleichende Chorologie der Zentraleuropaischen Flora. I Text, II Karten, Jena. Moore P, Webb J, Collinson M (1991) Pollen analysis. 2nd ed. Blackwell Scientific Publications, Oxford. Moriset P (1978) Chromosome numbers in Ononis L. series Vulgares Sirj. Watsonia 12: 145-153. Pavlova D, Tosheva A (2000) Reports 1208-1212. In: Kamari G et al. (ed) Mediterranean chromosome number reports-10. Flora Mediter 10: 419-423. Planchais N (1964) Le pollen de quelques papilionacees mediterraneennes et submediterraneennes. Pollen et Spores 6 (2): 515-526. Polhill R, Raven P (1981) Advances in Legume Systematics. Part 1, Royal Bot Gard Kew. Punt W, Blackmore S, Nilsson S, Le Thomas A (1994) Glossary of pollen and spore terminology. Lab Palaeobot Palynol, Utrecht. Reille M (1992) Pollen et spores d’Afrique du nord. Lab Bot Hist Palynol, Marseille. Sirjaev G (1932) Generis Ononis L. revisio critica. Beih Bot Centr 49 (2): 381-665. Tarnavschi I, Serbanescu-Jitariu G, Mitroiu-Radulescu N, Radulescu D (1990) Monografia polenului florei din Romania. Bucharest, 3: 14-44.

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