Effects of Elephants on Ecosystems and Biodiversity

Abstract

ISBN 978 1 86814 479 2All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the express permission, in writing, of both the author and the publisher.Cover photograph by Donald Cook at stock.xchng Cover design, layout and design by Acumen Publishing Solutions, JohannesburgPrinted and bound by Creda Communications, Cape Town Foreword SOUTH AFRICA and its people are blessed with diverse and thriving wildlife. We are also a developing economy with a growing population. From these facts emerges the particular situation of having most of our protected areas surrounded by land that has been transformed, to a greater or lesser extent, by human development. Large mammals, such as elephants, no longer roam the entire landscape, and their populations are no longer completely governed by the laws of nature. Protecting elephants and the ecological systems in which they exist in a practical and sustainable way that balances the needs of humans, elephants and the environment is a challenge to which I am committed.This Assessment was undertaken to reduce the degree of scientific uncertainty associated with decisions that must be made very soon and in the medium-to-long term. It helps to evaluate the costs and benefits associated with each choice, both in economic and ecological terms, and clarifies the legal framework within which they must be made. Collectively the chapters in this report reveal the many successes our country's experts, in collaboration with their peers in neighbouring countries and abroad, have achieved in understanding elephants and their needs, in fields as diverse as veterinary science, ecology, animal behaviour, population and resource modelling.Importantly, the Assessment exposes important gaps in our understanding and thus outlines necessary future avenues of research. This Assessment represents a key milestone in an ongoing Elephant Research Programme.Science does not provide all the information required to resolve the difficult issues raised by the management of elephant in a changing and humandominated world. Many of the required decisions have a strong element of human values implicit in them. How do South Africans wish to treat the other species with which they share our land? Extensive consultation and careful consideration of the values expressed by a wide range of stakeholders is also an essential part of the process of managing elephant in a democratic country.I am grateful to the many experts and interested persons who invested their time, experience and intellect to deliver this Assessment. I look forward to their continued engagement on the issue of elephant management, which is of great interest to many. Marthinus van Schalkwyk Minister of Environmental Affairs and Tourism, 2008 ContentS LiSt oF FigureS LiSt oF boxeS About the AuthorS And ContributorS Brandon Anthony is an assistant professor at the Department of EnvironmentalScienc...

Tree–grass co-existence in savanna: Interactions of rain and fire

“…The near-universal finding that tree cover increased when fires are excluded from savannas (Trapnell, 1959, Shackleton andScholes, 2000) and that elephants (see the several studies reviewed in Kerley et al, 2008), giraffe (Pellew, 1983) and other herbivores can substantially modify savanna structure, lend evidence to this school of thought.…”

Elevated elephant density does not improve ecotourism opportunities: convergence in social and ecological objectives

“…These charismatic species have positive consequences for the social-ecological system in terms of both the ecological processes that they provide (Kerley et al 1995, Rouget et al 2006) and the income and support that they generate through ecotourism (Geach 1997). However, there are also negative aspects associated with the stocking of elephants in protected areas, especially at high densities, where they have been implicated in declines in biodiversity (Cumming et al 1997, Kerley et al 2008, particularly in the subtropical thicket characteristic of the AENP (Kerley and Landman 2006). Elephants are very large, social, and equipped with specialized feeding adaptations (the trunk and tusks) that allow them to forage differently than other, smaller herbivores (Kerley et al 2008).…”

“…However, there are also negative aspects associated with the stocking of elephants in protected areas, especially at high densities, where they have been implicated in declines in biodiversity (Cumming et al 1997, Kerley et al 2008, particularly in the subtropical thicket characteristic of the AENP (Kerley and Landman 2006). Elephants are very large, social, and equipped with specialized feeding adaptations (the trunk and tusks) that allow them to forage differently than other, smaller herbivores (Kerley et al 2008). Studies have documented how this megaherbivore influences the fate of more plant species than any other large herbivore (Barnes 2001, Kerley andLandman 2006).…”

“…Studies have documented how this megaherbivore influences the fate of more plant species than any other large herbivore (Barnes 2001, Kerley andLandman 2006). Elephants exhibit a destructive feeding action that may lead directly to the death of trees through felling or uprooting, or indirectly through bark removal (Kerley et al 2008). In Botswana, elephants have played a significant role in the disappearance of the riverine acacia woodlands along the Chobe River (Barnes 2001, Skarpe et al 2004).…”

“…In the subtropical thicket of South Africa, high elephant densities cause a reduction in plant biomass (Pentzhorn et al 1974, Barrett andHall-Martin 1991) and the loss of a range of plant species, including a number of endemic or near-endemic succulents and geophytes (Moolman and Cowling 1994, Lombard et al 2001, Kerley and Landman 2006. It has also been postulated that changes in habitat structure brought about by high elephant numbers in the AENP and elsewhere have reduced the richness and abundance of a variety of animal species (Novellie et al 1996, Fenton et al 1998, Kerley and Landman 2006, Kerley et al 2008. Maintaining species diversity is not only the core objective of protected areas but also this diversity plays an important role in attracting tourists to protected areas (Okello and Yerian 2009).…”