The Biology of African Savannahs

341 Pages·2015·7.87 MB·English

by  Bryan Shorrocks

The Biology of African Savannahs
THE BIOLOGY OF HABITATS SERIES
This attractive series of concise, affordable texts provides an integrated overview of the design,
physiology, and ecology of the biota in a given habitat, set in the context of the physical environ-
ment. Each book describes practical aspects of working within the habitat, detailing the sorts of
studies which are possible. Management and conservation issues are also included. The series
is intended for naturalists, students studying biological or environmental science, those begin-
ning independent research, and professional biologists embarking on research in a new habitat.
The Biology of Streams and Rivers
Paul S. Giller and Björn Malmqvist
The Biology of Soft Shores and Estuaries
Colin Little
The Biology of the Deep Ocean
Peter Herring
The Biology of Lakes and Ponds, 2nd Edition
Christer Brönmark and Lars-Anders Hansson
The Biology of Soil
Richard D. Bardgett
The Biology of Mangroves and Seagrasses, 2nd Edition
Peter J. Hogarth
The Biology of Polar Regions, 2nd Edition
David N. Thomas et al.
The Biology of Deserts
David Ward
The Biology of Caves and Other Subterranean Habitats
David C. Culver and Tanja Pipan
The Biology of Alpine Habitats
Laszlo Nagy and Georg Grabherr
The Biology of Rocky Shores, 2nd Edition
Colin Little, Gray A. Williams and Cynthia D. Trowbridge
The Biology of Coral Reefs
Charles R.C. Sheppard, Simon K. Davy, and Graham M. Pilling
The Biology of Disturbed Habitats
Lawrence R. Walker
The Biology of Freshwater Wetlands, 2nd Edition
Arnold G. van der Valk
The Biology of Peatlands, 2nd Edition
Håkan Rydin and John K. Jeglum
The Biology of African Savannahs, 2nd Edition
Bryan Shorrocks and William Bates
The Biology
of African
Savannahs
SECOND EDITION
Bryan Shorrocks Ph.D.
Emeritus Professor University of Leeds
and Honorary Professor University of York
Environment Department
University of York
Heslington, York
United Kingdom
and William (Bill) Bates, Ph.D.
Wildlife Bioacoustics Research
Professor Emeritus of Zoology
University of British Columbia
Kelowna, British Columbia
Canada
1
The Biology of African Savannahs. Second Edition. Bryan Shorrocks & William Bates.
© Bryan Shorrocks & William Bates 2015. Published 2015 by Oxford University Press.
1
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© Bryan Shorrocks & William Bates 2015
The moral rights of the authors have been asserted
First Edition published in 2007
Impression: 1
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British Library Cataloguing in Publication Data
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Library of Congress Control Number: 2014946890
ISBN 978–0–19–870270–2 (hbk.)
ISBN 978–0–19–870271–9 (pbk.)
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Links to third party websites are provided by Oxford in good faith and
for information only. Oxford disclaims any responsibility for the materials
contained in any third party website referenced in this work.
Bryan and William would like to dedicate this book to Jo and Jeannie who
also love Africa and have supported them in all their adventures.
Preface to the First Edition
This book is an introduction to African savannahs and their biology, concen-
trating on large mammal ecology, behaviour, and conservation. Although it
is a book on savannahs I hope that it sets out its ideas within a general frame-
work of ecological and behavioural ideas.
In my 40 years as an ecologist I have worked on both temperate and tropic-
al terrestrial ecosystems. I have carried out field surveys, field experiments
and built mathematical and computer models. I believe all these elements
are essential for understanding Nature, and they all appear in this book.
You cannot simply watch wildlife populations and communities in order
to understand how they function. You have to employ field manipulations,
either natural or artificial, to tease out the possibilities. You have to describe
what you see not just in words but in mathematical models, to allow your
less precise verbal suspicions to be tested. And savannah ecology must fit
comfortably within the framework of general ecological ideas. There can be
no special pleading or special mechanisms that other ecologists just don’t
understand. I have tried to present such an encompassing view of savannah
ecology and behaviour.
African savannahs are magical places. The brightness of the light, the inten-
sity of the colours, and the beauty and excitement of the wildlife, and of
course the people. These savannahs are worth preserving for future gener-
ations and I hope, in a small way, this book will generate an interest that helps
them survive.
I would like to thank all the people that have helped in my savannah work in
East Africa, in particular the people at the Mpala Research Centre, in Laiki-
pia, Kenya. Their help and insights have been invaluable during my frequent
stays there. Finally my thanks to Paul Ward who, over several beers, over
several nights, while running an undergraduate field course in Derbyshire
reawakened my latent interest in Africa and its wildlife.
Bryan Shorrocks
June 2007
Preface to the Second Edition
Once again this book is an introduction to African savannahs and their biol-
ogy, concentrating on large mammal ecology, behaviour, and conservation.
However, this second edition contains new material and many updates. These
include hundreds of new references, new technique boxes, updated distribu-
tion maps for the mammals and some birds, and an expanded focus on the
conservation of African savannahs. Also new to the second edition is a com-
panion website, <http://africansavannahs. shawwebspace.ca/>. This website
contains additional information pertaining to African savannahs, including
Soundscape ecology audio files and analysis, videos, the latest news on con-
servation efforts, new journal article citations, and an interactive blog. As BS
said in the preface to the first edition, these savannahs are worth preserving
for future generations and we hope, in a small way, this book will again gen-
erate an interest that helps them survive. Hopefully many of our readers will
be young Africans, as the survival of African national parks and reserves will
ultimately be determined by future generations of Africans.
We would like to thank all the people that have helped us in our savannah
work in southern Africa and East Africa. BS is grateful to the people at the
Mpala Research Centre, in Laikipia, Kenya, and the staff at Etosha National
Park, Namibia. Their help and insights have been invaluable during frequent
stays there. WB is especially grateful to Chris McBride, who runs a camp in
Zambia, for transmitting insights related to lion behaviour. The authors also
want to thank the staff at OUP, especially Lucy Nash and Ian Sherman, for
their continual encouragement and help.
Bryan Shorrocks and William Bates
November 2014

Contents
1 Savannahs 1
Distribution world-wide 2
African savannahs 9
2 The Vegetation 27
Rainfall, plant biomass and grass–tree mixture 27
Morphology and life history 30
Grasses 38
Trees 41
Local vegetation patterns: the Serengeti–Mara ecosystem 57
3 The Animals 65
The insects 65
The birds 69
The mammals 74
4 Single-species Populations 137
Estimating numbers 138
What changes numbers? 153
Population models 163
Other species in other areas 168
5 Species Interactions 182
Predator–prey type interactions (+ −) 183
Competitive interactions (− −) 210
Mutualistic interactions (+ +) 227
6 The Savannah Community and Its Conservation 237
Energy flow and food webs 238
Assembly rules 252