Advances in ECOLOGICAL RESEARCH VOLUME 19 This Page Intentionally Left Blank Advances in ECOLOGICAL RESEARCH Edited by M. BEGON Department of Zoology, University of Liverpool, Liverpool, L69 3BX, UK A. H. FITTER Depurtment of Biology, University of York. York, YOI SDD, UK E. D. FORD Center for Quantitative Science, University of Washington, 3737 15th Avenue, Seattle, W A 98195, USA A. MACFADYEN 23 Mountsandel Roud, Coleraine, Northern Ireland VOLUME 19 ACADEMIC PRESS Hurcourt Brace Jovunovich, Publishers London San Diego New York Berkeley Boston Sydney Tokyo Toronto This book IS printed on acid-free paper (m) ACADEMIC PRESS L T D 24/28 Oval Road London NWI United S ~ u t e sEdition published by ACADEMIC PRESS INC. San Diego, CA 92101 Copyright N ' J 1989 by ACADEMIC PRESS LIMITED AN Rights Reserved No part of this book may be reproduced in any form by photostat, microfilm, o r any other means, without written permission from the publishers British Library Cataloguing in Publication Data Advances in ecological research. Vol. 19 I . Ecology 1. Begon. Michael 574.5 ISBN G12413919-7 Typeset by Latimer Trend & Company Ltd, Plymouth Printed in Great h i t d i n by T. J . Press (Padstow) Ltd.. Padstow, Cornwall Contributors to Volume 19 F. ATHIAS-BINCHE, Laboratoire Arago, 66650 Banyuls-Sur-Mer, France. E. A. BERNAYS, Department of Entomology, University of Arizona, Tucson. Arizonu 85721, USA. M. BI LGENER, Biological Sciences Department, Boston University, Boston, Mass. 02215. USA. G . COOPER DRIVER, Biological Sciences Department, Boston University, Boston, Mass. 02215, USA. D. EAMUS, Institute of Terrestrial Ecology, NERC, Bush Estate. Penicuik, Midlothian, EH26 OQB. *T. M. FARRELL, Department of Zoology, Oregon State University, Corvallis, Oregon 97331, USA. H. C . FRITTS, Laboratory of Tree-Ring Research, University of Arizona, Tuscon. Arizona 85721, USA. P. G. JARVIS, Department of Forestry and Natural Resources, University of Edinburgh, The King’s Buildings, Mayjeld Road, Edinburgh EH9 3JU. B. A. MENGE, Department of Zoology, Oregon State University, Corvallis, Oregon 97331, USA. R. K . MONSON. Department of Environmental. Population and Organismic Biology, Campus Box 334, University of Colorado, Boulder, Colorado 80309, U S A . T. W . SWETNAM, Laboratory of Tree-Ring Research. University of Arizona, Tuscon, Arizona 85721, U S A . *Present address: Hopkins Marine Station, Stanford Universitj!, PacIfic Grove, California 93950, U S A This Page Intentionally Left Blank Preface The new team of editors are pleased to see the production of this, their second volume in the series Advances in Ecological Research. The six papers in this volume cover, in the tradition of the series, a wide variety of topics: population and community ecology, evolutionary and physiological ecology, animals, plants and plant-animal interactions, and marine and terrestrial habitats. We are certain that this breadth will be maintained in future volumes and would particularly like to encourage potential authors to review, in a readable but rigorous fashion, areas of ecology which they feel should be brought to the attention of a wider ecological audience. Ecology is a science which is forever in danger of falling apart into separate, virtually independent sub-disciplines. Advances in Ecological Research will be an important vehicle in maintaining the essential unity of the subject. The increase in global mean concentration of carbon dioxide, from the mid-eighteenth century to the present day is well established, and the concentration is still rising rapidly. Popular attention has focused recently on the global warming that has in the past and is likely in the future to result from this - the