Wytham Woods Oxford's Ecological Laboratory
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Wytham Woods This page intentionally left blank Wytham Woods Oxford’s Ecological Laboratory Editors P.S. Savill Oxford Forestry Institute Department of Plant Sciences University of Oxford C.M. Perrins Edward Grey Institute Department of Zoology University of Oxford K.J. Kirby Natural England Peterborough N. Fisher Conservator of Wytham Woods University of Oxford 1 1 Great Clarendon Street, Oxford ox2 6dp Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York Oxford University Press 2010 The moral rights of the authors have been asserted Database right Oxford University Press (maker) First published 2010 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose the same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging-in-Publication Data Savill, Peter S. Wytham Woods : Oxford’s Ecological Laboratory / Peter Savill, Christopher Perrins, Keith Kirby. p. cm. ISBN 978-0-19-954320-5 (hardback) 1. Forest ecology—Research—England—Wytham Wood. 2. Naturla history—England—Wytham Wood. 3. Wytham Woods (England) I. Perrins, Christopher M. II. Kirby, K. J. III. Title. QH138.W95S28 2010 577.309425’7—dc22 2010000246 Typeset by SPI Publisher Services, Pondicherry, India Printed in Great Britain by the MPG Books Group in the UK ISBN 978–0–19–954320–5 13579108642 Contents Preface ix Acknowledgements xi Contributors xii 1 Introduction 1 C. M. Perrins 1.1 History of British woodland 3 1.2 The forest returns 3 1.3 A green mantle 4 1.4 From forest to farmed landscape 5 1.5 Brief history of Wytham 7 1.6 The ffennels and Wytham 9 1.7 The Woods today 13 1.8 Conclusion 17 2 The Physical Environment 19 M. E. Taylor, M. D. Morecroft, and H.R. Oliver 2.1 Location 19 2.2 Topography 21 2.3 Climate 21 2.4 Geology and Soils 24 2.5 Hydrology 26 2.6 Pollution 27 3 Woods ancient and modern—land use history 29 C. W. D. Gibson and K. J. Kirby 3.1 Introduction 29 3.2 The early times 29 3.3 The landscape up to the late eighteenth century 32 3.4 Exploiting the Woods 35 3.5 The legacy of the fth Earl of Abingdon 36 3.6 Stasis and decline in the Woods 38 3.7 The development of a research estate 38 4 The Woods in the modern landscape 43 K. J. Kirby and C. W. D. Gibson 4.1 Introduction 43 4.2 Wytham in the context of Oxfordshire’s woods 43 vi Contents 4.3 Grassland 48 4.4 Fens and other wetland 50 4.5 Movement within the Woods and between the Woods and the surroundings 51 4.6 Changes in the relationship between the Woods and its surroundings 52 4.7 Conclusion 53 5 The Trees in the Woods 1945–2007 57 K. J. Kirby 5.1 Active forestry management 1945–1963 57 5.2 Minimum intervention and ‘near-natural’ stand development 60 5.3 Long-term studies of stand structure and composition 60 5.4 Tree physiology 69 5.5 Composition and structure of the shrub layer 70 5.6 The changes in woodland structure and its possible causes 70 5.7 Old growth and open space 72 5.8 Twenty- rst century changes 74 6 The fl owers of the forest 75 K. J. Kirby and M. D. Morecroft 6.1 Introduction 75 6.2 The Woods in a wider botanical context 75 6.3 Vegetation patterns—soil and woodland history 76 6.4 The woodland ora and stand dynamics 79 6.5 Other changes in the woodland ora 1974–1999 81 6.6 Changes in Wytham Woods compared to trends elsewhere in the country 83 6.7 Bramble as a key species 87 6.8 Conclusions 88 7 The ecology of Upper Seeds—an old- eld succession experiment 91 C. W. D. Gibson 7.1 Introduction: patterns in space and dynamics 91 7.2 Patterns in time: the nature of change 91 7.3 The experimental system 92 7.4 Colonization and species pools 95 7.5 Early and mid successional communities during an English old- eld succession 97 7.6 Invasion and decline of Arrhenatherum elatius (false oat-grass) 99 7.7 How does the grassland on Upper Seeds compare with other grassland? 102 Contents vii 7.8 Structure, plant taxonomy, and invertebrates 104 7.9 Invertebrate movement between patches 106 7.10 Conclusion 108 8 Invertebrates 109 C. Hambler, G. R. W. Wint, and D. J. Rogers 8.1 Introduction 109 8.2 Pioneers of ecology and ecological genetics 110 8.3 The Wytham Ecological Survey 113 8.4 Invertebrates, habitat specialisms, and landscape management 114 8.5 Studies of cover and succession 114 8.6 Understanding animal abundance and density 116 8.7 Stability of complex systems 120 8.8 Ecological Energetics 121 8.9 The origins of Behavioural Ecology 121 8.10 Farm wildlife 122 8.11 Wytham’s invertebrates and British conservation management 123 8.12 Invertebrate ecology in teaching 126 8.13 Improved sampling methodology and indicator groups 128 8.14 Present and future work 129 8.15 Notable invertebrates in Wytham and their requirements 132 8.16 The winter moth—an unlikely superstar 134 8.17 The ‘life table’ of a species 137 8.18 From moths to generalities 143 8.19 Acknowledgements 144 9 Birds 145 C. M. Perrins and A. G. Gosler 9.1 Introduction 145 9.2 Bird species in Wytham 145 9.3 Changes in species 146 9.4 The Wytham Tit Study 149 9.5 The future—where next? 163 9.6 Other Bird studies in Wytham 165 9.7 Conclusion 171 10 The Mammals of Wytham Woods 173 C. D. Buesching, J. R. Clarke, S. A. Ellwood, C. King, C. Newman, and D. W. Macdonald 10.1 Wytham’s small mammals 173 10.2 Deer 182 10.3 Weasels 184 viii Contents 10.4 Foxes 185 10.5 Wytham’s Badgers 187 10.6 Hedgehogs 194 10.7 Squirrels 195 10.8 Amateur Volunteers as Biodiversity Monitors 195 11 Conservation Management of Wytham Woods 197 N. Fisher, N. D. Brown, and P. S. Savill 11.1 Conservation management before 1900 197 11.2 Twentieth century conservation 198 11.3 Management by Oxford University 200 11.4 Wytham’s role in national conservation policy 201 11.5 Conservation management: the last 60 years 202 11.6 Woodland Management 203 11.7 Veteran trees 205 11.8 Deer 206 11.9 Grey squirrels 209 11.10 Grasslands 211 11.11 Management of rides and other woodland edges 212 11.12 Ponds and Fen 212 11.13 Con icts between Research and Conservation 213 11.14 Promoting Public Access 213 11.15 Monitoring the effectiveness of conservation management 213 11.16 Future Challenges 214 11.17 Climate change 215 11.18 Conclusion 215 12 Wytham in a changing world 217 M. D. Morecroft and M. E. Taylor 12.1 The Environmental Change Network 217 12.2 Upper Seeds climate change experiment 221 12.3 Tree growth and interactions with the atmosphere 223 12.4 Conclusions 228 References 231 Index 253 Preface John Krebs (Lord Krebs, of Wytham) If there were a Nobel Prize for Ecology, and if you could award it to a place rather than a person, Wytham Woods would surely be a prime candidate. It is almost certainly unmatched anywhere in the world as a place of sustained, intensive ecological research extending over nearly three quarters of a century. The ecological concepts and discoveries based on work carried out at Wytham over the past seven decades read like a text book of ecology. Here are just a few examples: density-dependence and population regulation, the evolution of reproductive rates, the heritability of ecologically important traits, the response of populations and communi- ties to climate change, natural selection in action, the relationship between stability and complexity in ecosystems, and the chemical defences of plants against insects. How did this come about? Not as a result of a long-term strategic plan, but rather as a result of a lucky concatenation of circumstances. These included the donation of the Woodlands to the University, giving long-term security, the vision of a small number of key individuals, including David Lack, Charles Elton and George Varley, who collectively and individually not only realised the opportunities and benefi ts of long-term ecologi- cal research, but also had the scientifi c vision to create, in large part, the new scientifi c discipline of ecology.