The Ecology of Seeds
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- Bu səhifədəki naviqasiya:
- 1 Life histories, reproductive strategies and allocation 1
- 2 Pre-dispersal hazards 32
- 3 Seed dispersal 47
- 4 Soil seed banks 76
- 5 Seed dormancy 97
- 6 Germination 110
- 7 Post-dispersal hazards 136
- 9 Gaps, regeneration and diversity 163
| The Ecology of Seeds How many seeds should a plant produce, and how big should they be? How often should a plant produce them? Why and how are seeds dispersed, and what are the implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function. M i c h a e l F e n n e r is a senior lecturer in ecology in the School of Biological Sciences at the University of Southampton, UK. He is author of Seed Ecology (1985) and editor of Seeds: The Ecology of Regeneration in Plant Communities, 2nd edition (2000). K e n T h o m p s o n is a research fellow and honorary senior lecturer in the Department of Animal and Plant Sciences at the University of Sheffield, UK. He is author of The Soil Seed Banks of North West Europe (1997) and An Ear to the Ground: Garden Science for Ordinary Mortals (2003). www.cambridge.org 0521653681 Michael Fenner and Ken Thompson Frontmatter More information
The Ecology of Seeds
Michael Fenner University of Southampton, Southampton, UK Ken Thompson University of Sheffield, Sheffield, UK www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information p u b l i s h e d b y t h e p r e s s s y n d i c a t e o f t h e u n i v e r s i t y o f c a m b r i d g e The Pitt Building, Trumpington Street, Cambridge, United Kingdom c a m b r i d g e u n i v e r s i t y p r e s s The Edinburgh Building, Cambridge, CB2 2RU, UK 40 West 20th Street, New York, NY 10011--4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia Ruiz de Alarc´ on 13, 28014 Madrid, Spain Dock House, The Waterfront, Cape Town 8001, South Africa http://www.cambridge.org C M. Fenner and K. Thompson 2004 This book is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2004 Printed in the United Kingdom at the University Press, Cambridge Typeface Swift 9.5/14 pt. System L A TEX 2 ε [tb] A catalogue record for this book is available from the British Library Library of Congress Cataloguing in Publication data Fenner, Michael, 1949-- The ecology of seeds/by Michael Fenner & Ken Thompson. p. cm. Includes bibliographical references and index. ISBN 0 521 65311 8 (hardback) -- ISBN 0 521 65368 1 (paperback) 1. Seeds -- Ecology. 2. Plants -- Reproduction. I. Thompson, Ken, 1954-- II. Title. QK661.F45 2004
581.4 67 -- dc22 2004045661 ISBN 0 521 65311 8 hardback ISBN 0 521 65368 1 paperback The publisher has used its best endeavours to ensure that URLs for external websites referred to in this book are correct and active at the time of going to press. However, the publisher has no responsibility for the websites and can make no guarantee that a site will remain live or that the content is or will remain appropriate. www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information
Contents List of boxes page viii
Preface ix
1 1.1 Sexual vs. asexual reproduction in plants 1 1.2 Life histories and survival schedules 3 1.3 Variability of seed crops 12 1.4 The cost of reproduction 16 1.5 Reproductive allocation and effort 20 1.6 Seed size and number 23 1.7 Phenotypic variation in seed size 29
2.1 Fruit and seed set 32 2.2 Incomplete pollination 33 2.3 Ovule abortion 34 2.4 Resource limitation 39 2.5 Pre-dispersal seed predation 40
3.1 Wind dispersal 47 3.2 Dispersal by birds and mammals 51 3.3 Myrmecochory 60 3.4 Water and ballistic dispersal 62 3.5 Man, his livestock and machinery 63 3.6 Evolution of dispersal 67 3.7 Some final questions 72 v
© Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information
vi Contents
4 Soil seed banks 76 4.1 Seed banks in practice 78 4.2 Dormancy and seed size 80 4.3 Predicting seed persistence; hard seeds 82 4.4 Seed-bank dynamics 86 4.5 Serotiny 89 4.6 Ecological significance of seed banks 89 5 Seed dormancy 97 5.1 Types of seed dormancy 97 5.2 The function of seed dormancy 98 5.3 Defining dormancy 99 5.4 Microbes and seed dormancy 103 5.5 Effects of parental environment on dormancy 104
6.1 Temperature and germination 110 6.2 Responses of seeds to light 116 6.3 Water availability during germination 121 6.4 The soil chemical environment 123 6.5 Effects of climate change 131
7.1 Post-dispersal predation 136 7.2 Loss to pathogens 140 7.3 Fatal germination at depth 141 7.4 Loss of viability with age 143 8 Seedling establishment 145 8.1 Early growth of seedlings 145 8.2 Seedling morphology 146 8.3 Relative growth rate 148 8.4 Seedling mineral requirements 152 8.5 Factors limiting establishment 155 8.6 Mycorrhizal inoculation of seedlings 159 8.7 Facilitation 160 8.8 Plasticity 161 9 Gaps, regeneration and diversity 163 9.1 Gaps, patches and safe sites 163 9.2 ‘Gaps’ difficult to define and detect 164 www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information
Contents vii
9.3 Limitations to recruitment in gaps 167
9.4 Microtopography of soil surface 172
9.5 Gaps and species diversity 176
References 179
Index 241
www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information Boxes 1.1 Trade-offs page 4 2.1 Low seed set in sparse populations: the Allee effect 36 3.1 Why do plants have poisonous fruits? 58 3.2 Parent-offspring conflicts in germination and dispersal 74 4.1 Is seed persistence in soil a plant trait? 85 6.1 Response to smoke 129 9.1 Seed traits and plant abundance 169 9.2 Role of leaf litter in regeneration 175 viii
www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information Preface In 1985 one of us published a small book called Seed Ecology. It contained 42 000 words and cited 334 references. It was successful in introducing a genera- tion of ecologists to our subject, but it is now seriously out of date and has been out of print for some time. The book you are now holding contains 94 000 words and cites 1117 references. Only a small part of this expansion can be attributed to covering any part of the subject in more detail; nearly all of it reflects simply the massive increase in interest in seed ecology in the past 20 years. One sign of this expansion was the launch in 1991 of the journal Seed Science Research, provid- ing a major platform for fundamental work in seed biology, including ecology; 37 of our cited references are from that journal. More recently, the International Society for Seed Science was founded in 2000. This society sponsors meetings on all aspects of seed science, including, for the first time in 2004, a major inter- national meeting on seed ecology. Our cited references also reflect this recent growth: 82% are from the past two decades, while 15% are post-1999. Recent work in this field has transformed our understanding of many aspects of seed ecology, especially dispersal, storage in the soil and the ecological role of seed dormancy. There has also been increasing recognition that regeneration from seed has fundamental impacts on the diversity and composition of plant communities; seed ecology has never seemed more relevant to ‘mainstream’ plant ecology. Nevertheless, we have not lost sight of our debt to the pioneers who laid the foundations for later work. Many of the most important figures in the history of ecology, including Darwin, Harper and Salisbury, made significant contributions to seed ecology. In this book, we attempt to synthesize the current information available on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and the costs and compromises involved. Special attention here is given to the interesting topic of seed size. The text then follows the progress of seeds through the stages of their life cycle in a ix www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information
x Preface
roughly chronological sequence: seed maturation, dispersal, storage in the soil, dormancy, germination and seedling establishment. The final chapter gives an account of the role that canopy gaps play in the regeneration of plants in the field. Throughout the book, various specialized topics (which might otherwise have interrupted the flow of the text) are presented in self-contained boxes. We aimed to present a broadly representative overview of the current lit- erature rather than a comprehensive review of it. We have tried to present a reasonably balanced account of the field in a way that reflects current thinking. Nevertheless, where we have strong feelings on particular topics, we have not refrained from nailing our colours to the mast. When this happens, for exam- ple concerning the definition of dormancy, we hope you find our arguments convincing. We hope that this text will be useful to students of plant ecology at all levels. The regeneration of plants from seed involves a very wide range of ecological concepts of current interest, from reproductive strategies to the maintenance of species diversity. Pollination, seed dispersal and seed predation all offer inter- esting insights into the evolution of plant--animal interactions. The numerous trade-offs encountered (e.g. between seed size and number, early reduced repro- duction vs. delayed increased fecundity, early high-risk germination vs. delayed safer germination, etc.) offer scope for theoretical investigations and modelling. We hope that the work reported here from the literature will stimulate students into devising their own experimental investigations. Excellent undergraduate projects on seed ecology can often be carried out in the field with a minimum of technical resources. Several colleagues provided substantially new figures or new versions of pub- lished figures. We would particularly like to thank Costas Thanos, Mary Leck and Bego˜ na Peco. Otherwise, the text is entirely our own work. We can there- fore assert cheerfully that any errors and omissions are ours alone. www.cambridge.org © Cambridge University Press Cambridge University Press 0521653681 - The Ecology of Seeds Michael Fenner and Ken Thompson Frontmatter More information Yüklə 129,48 Kb. Dostları ilə paylaş:
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