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P R O B L E MS IN M A N A G E M E NT
OF L O C A L LY A B U N D A NT W I LD
M A M M A LS
Edited by
PETER A. J E W E LL
SIDNEY H O LT
St. Johns' College
Cambridge, United Kingdom
Associate Editor
D O N NA H A RT
International Fund for Animal Welfare
Yarmouth Port, Massachusetts
1981
ACADEMIC PRESS
A Subsidiary of Harcourt Brace Jovanovich, Publishers
New York London
Paris San Diego San Francisco Sao Paulo Sydney Tokyo Toronto
COPYRIGH T © 1981 B Y ACADEMI C PRESS , INC .
ALE RIGHTS RESERVED.
NO PART OF THIS PUBLICATION MAY BE REPRODUCED OR
TRANSMITTED IN ANY FOR M OR BY ANY MEANS, ELECTRONIC
OR MECHANICAL, INCLUDING PHOTOCOPY, RECORDING, OR ANY
INFORMATION STORAGE AND RETRIEVAL SYSTEM, WITHOUT
PERMISSION IN WRITING FRO M THE PUBLISHER.
ACADEMIC PRESS, INC.
Ill Fifth Avenue , New York, New York 1000 3
United Kingdom Edition published by
ACADEMIC PRESS, INC. (LONDON) LTD.
24/2 8 Oval Road, Londo n NW1 7DX
Library of Congress Cataloging in Publication Data
Management of Locally Abundant Wild Mammals: a Workshop
to Examine the Need for and Alternatives to the
Culling of Wild Animals (1980 : Yarmouth Port, Mass.)
Problems in management of locally abundant wild mammals.
"Proceedings of the Management of Locally Abundant
Wild Mammals: a Workshop to Examine the Need for and
Alternatives to the Culling of Wild Animals, sponsored by
the International Fund for Animal Welfare in Yarmouth Port,
Massachusetts, September 29-0ctober 3, 1980"—Verso t.p.
Includes index.
1. Wildlife management—Congresses. 2. Mammal populations
—Congresses. I. Jewell, Peter Arundel. II. Holt, Sidney
Joseph, Date. III. Hart, Donna. IV. International Fund for
Animal Welfare. V. Title. VI. Title: Culling of Wild Animals.
SK352.M36 1980 639.9'79 81-20529
ISBN 0-12-385280-3 AACR2
PRINTED IN THE UNITED STATES OF AMERICA
81 82 83 84 9 8 7 6 5 4 3 2 1
CONTRIBUTORS
Numbers in parentheses indicate the pages on which the authors' contributions begin.
John R. Beddington (205), International Institute for Environment and
Development, London Wl, England
R. Η. V. Bell (69), Department of National Parks and Wildlife, Kasungu
National Park, Kasungu, Malawi
Graeme Caughley (7), Division of Wildlife Research, CSIRO, Lyneham, Can
berra, A. C. T. 2602, Australia
Douglas G. Chapman (193), Center for Quantitative Science, University of
Washington, Seattle, Washington 98195
Stephen Cobb (181), Department of Zoology, University of Nairobi, Nairobi,
Kenya
David Η. M. Cumming (91), Department of National Parks and Wildlife
Management, Causeway, Salisbury, Zimbabwe
W. D. Densham (21), Natal Parks Board, Pietermaritzburg, South Africa
S. K. Eltringham (277), Department of Applied Biology, University of Cam
bridge, CB2 3DX, England
James A. Estes (167), National Fish and Wildlife Laboratory, Center for
Coastal Marine Studies, University of California, Santa Cruz, California
95064
John Hanks (21), Institute of Natural Resources, Pietermaritzburg, South
Africa
John Harwood (151), Natural Environment Research Council, Sea Mammal
Research Unit, Cambridge CB3 OET, England
R. K. Hofmann (259), Proyecto Vicuna, Nazca, Peru
J. F. Jooste (21), Cape Department of Nature and Environmental Conserva
tion, Stellenbosch, South Africa
ix
χ CONTRIBUTORS
W. J. Jordan (277), People's Trust for Endangered Species, Guildford, Surrey
GUI 3EH, England
S. C. J. Joubert (21), National Parks Board of Trustees, Skukuza, Kruger
National Park, South Africa
David R. Klein (119), Alaska Cooperative Wildlife Research Unit, University
of Alaska, Fairbanks, Alaska 99701
David M. Lavigne (151), Department of Zoology, University of Guelph,
Guelph, Ontario, NIG 2W1, Canada
Richard M. Laws (217), British Antarctic Survey, Natural Environment
Research Council, Cambridge CB3 IPX, England
Burney J. Le Boeuf (291), Crown College, University of California, Santa
Cruz, California 95064
P. le Roux (21), Orange Free State Division of Nature Conservation, Bloem-
fontein, South Africa
Robert M. May (205), Department of Biology, Princeton University, Prince
ton, New Jersey 08544
P. leS. Milstein (21), Transvaal Nature Conservation Division, Pretoria, South
Africa
Imanuel Noy-Meir (233), Botany Department, The Hebrew University,
Jerusalem, Israel
K. C. Otte (259), Proyecto Vicuna, Nazca, Peru
Norman Owen-Smith (129), Center for Resource Ecology, Department of
Botany, University of the Witwatersrand, Johannesburg 2001, South
Africa
G. Carleton Ray (303), Department of Environmental Sciences, University of
Virginia, Charlottesville, Virginia 22903
A. R. E. Sinclair (247), institute of Animal Resource Ecology, University of
British Columbia, Vancouver, British Columbia V6R 1W5, Canada
G. L. Smuts (21), Natal Parks Board, Pietermaritzburg, South Africa
Brian H. Walker (57), Center for Resource Ecology, Department of Botany,
University of the Witwatersrand, Johannesburg 2001, South Africa
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xxii
PREFACE
The question of the degree to which protected animals may be allowed to in
crease in number, with possible detriment to human interests and to their own
habitat, is one which is of increasing concern to many people. Farmers,
pastoralists, and fishermen may be worried about competition from such animal
populations for space and fodder; managers of reserves, parks, and industries
based on exploitation of wild living resources may wish to see any "surplus" put
to economic use; persons and groups concerned with conservation or animal
welfare may have strong views about so-called culling or other programs for en
vironmental management; and local and national authorities may have to make
decisions aiming to strike a balance between diverse interests. All look, to some
extent, to scientists to help them with their problems. But it has become evident
that such help is limited by both the bounds of present biological knowledge and
the fact that such knowledge is but one of many factors that determine manage
ment policies.
The workshop, the results of which are given in this book, was sponsored by
the International Fund for Animal Welfare with a view to reexamining the scien
tific basis for possible management aimed at restraining local increase in
numbers of protected species. This limited objective was set with the expectation
that subsequent meetings, with somewhat different participation, would look at
practical aspects of reducing numbers or restraining growth where, for whatever
reason, it had to be concluded that such action was desirable. It was expected
also that further meetings would take up the related but nevertheless distinct
problem of exploitation of animal populations which interact directly with other
resources, such as seals or dolphins and commercially useful fish.
This book contains all the material, including selected case studies, prepared
as background for the workshop and revised by the authors afterwards in the
light of the discussions there. It contains also a report of the workshop, prepared
by a steering committee, based on drafts written during the course of the
meeting by various groups of participants, all of whom were consulted subse-
xiii
xiv PREFACE
quently. This report thus represents a general consensus of the participants,
although many of them would perhaps have reservations about details and the
form of expressing certain generalizations. As far as we know, this subject has
not previously been addressed in a comprehensive way, so the book will, we
hope, be of wide interest to other scientists, to managers, to members of various
public interest groups, and to users of natural living resources. It is admittedly
highly technical, but an attempt has been made to produce a text which is com
prehensible to those who are not specialists. We believe that although many
scientific questions remain unanswered, and the workshop drew attention to
areas of considerable uncertainty, a degree of sifting and synthesis of ideas and
findings has been possible, which leads to practical implications for environmen
tal management. Not least of the results of this project is a better identification
of the types of information needed for the definition of both management policy
and its implementation.
Apart from acknowledging the farsightedness of the sponsoring organization
in recognizing the need for a scientific review of the problem of "local over
abundance" and their timely action to facilitate it, thanks are due to all those
scientists who contributed to the workshop, and hence to this publication, by
writing working documents or making case studies, by participating in the
workshop, and by assisting in various ways to convert its results into this book.
Included in this acknowledgment and thanks is recognition of the input of Dan
Botkin, who chaired the workshop session on diagnostic characteristics.
Our special thanks go to Dan Morast of the International Fund for Animal
Welfare for coordinating the workshop, to Ruth Walicki, also of IFAW, for act
ing as workshop secretary, and to Mary Ann Pitchford and Donna Perdun for
typing the manuscript.
Sidney Holt
On behalf of the editors and members
of the Steering Committee
INTRODUCTION
Is wildlife ever too abundant? A great many species of
animals, once widespread and numerous, have been so reduced
by man's activities in changing the face of the earth that
they now survive in only a few small populations. Among
these animals are many of the world's larger and most attrac
tive mammals. All too many of these species are threatened
with extinction.
While this is so, it is an irony that these small popu
lations may become, apparently, locally overabundant and
create intense problems. The "elephant problem" is one of
the best known examples. Conservationists are faced with the
dilemma of a species in urgent need of protection over most
of its range, which occurs in such abnormally large numbers
in certain limited areas that the need to cull, perhaps by
killing, must be considered.
Is there any way out of this dilemma? What advice can
scientists who work in this field, particularly ecologists,
offer?
I. BACKGROUND
The International Fund for Animal Welfare, which has en
gaged in several operations to translocate wild animals as an
alternative to killing them, organized and funded a workshop to
pool the appropriate experiences of ecologists. (The suggestion
for this workshop was made at a meeting of the Species Survival
Commission of the International Union for the Conservation of
Nature and Natural Resources held in Cambridge, England in mid-
1979.)
As first viewed, the central task of the workshop was to
consider the dilemma of local overabundance of threatened
mammals, but it was recognized that this concept could lead
to too narrow an approach. For one thing, to speak of "over"
abundance prejudges the issue. Furthermore, while threatened
species present the real worries, many species that are not
endangered do become excessively abundant locally and do provide
PROBLEMS IN MANAGEMENT OF LOCALLY Copyright © 1981 by Academic Press, Inc.
ABUNDANT WILD MAMMALS 1 All rights of reproduction in any form reserved.
ISBN 0-12-385280-3
2 INTRODUCTION
valuable case histories. Hence the broader title of the work
shop <— "The Management of Locally Abundant Wild Mammals: A
workshop on the need for and alternatives to the culling of wild
animals." The purpose of the workshop was defined as a forum
for the discussion of the problems which can arise when man-
made changes permit a species to become so numerous locally it
seems to have an adverse effect on its food supply, its compete
itors, or even the species composition of the ecosystem,. This
objective statement hides a host of problems that are of press
ing urgency for those concerned with the conservation of wild
animals and their welfare. In particular the question of cull
ing — in whatever form it might take was the central issue.
As used in this volume, culling is defined as the selective
removal of animals from a population. Removal may be by killing
or by live capture and subsequent transportation of animals
elsewhere (either translocation to other areas of natural habi^
tat or for confinement in zoos and parks).
There are now many examples of national parks or conserva
tion areas where the culling of wild mammals has been carried
out as part of a management policy. Large numbers of certain
species have been killed to reduce their population density and
their impact on some other facet of the environment. Such
action is an extremely onerous and unpalatable task for con
servationists. In some places even relatively rare or threat
ened mammals have been culled by killing in the very reserves
originally set aside for their protection. Examples are hippo
potamus in Uganda, nyala in South Africa, elephant in many
African countries, vicuna in Peru, and grey seals in Britain.
Even if they were not classified as rare, many other spectac
ular mammals have been involved. This drastic intervention, in
attempts to manage wildlife areas, presents those in charge
with an agonizing dilemma.
II. ABUNDANCE AND OVERABUNDANCE
Why should such a contrary situation arise? As a result of
conservation efforts in recent decades many species and popula
tions of animals, the survival of which had been threatened by
human activities, have increased in numbers. The activities
that originally created the threats to survival were high
levels of hunting and changing land use leading to reduction
in the area or quality of the animals' habitats. Either or
both of these factors were present in any particular case and
to save the animal populations from extinction, reduction or
cessation of hunting was imposed and protected areas were
created.
