The social structure, distribution and demographic status of the African elephant population in the Central Limpopo River Valley of Botswana, Zimbabwe and South Africa by Sarah-Anne Jeanetta Selier Submitted in partial fulfilment for the requirements for the degree Magister Scientiae in Wildlife Management Centre for Wildlife Management Faculty of Natural and Agricultural Sciences University of Pretoria Pretoria Supervisor: Prof. W. Van Hoven Co-Supervisor: Dr. M. GaraÏ April 2007 AKNOWLEDGEMENTS No project can be a success without the support of organizations and individuals. This is especially true for a cross border project involving three different countries. My thanks and gratitude goes out to everyone who assisted in this project over the past years. Without your assistance and support this project would not have been a success. The hardest part of a project is obtaining enough funding to see the project through. My sincere gratitude to all the sponsors in this project who all contributed generously and received little in return. NOTUGRE, Mashatu Game Reserve, The Peace Park Foundation, REWF, Lenova laptops, Massachusetts Audubon Society, Pittsburgh Zoo, Philadelphia Zoo and Wings4Wildlife. Several individuals have contributed financially to the project, Mr. Geoff Norris, Mr. Marcel Burgauer, Miss Marlu Sulzer, Miss Chris Burlock, and John Dewar. To NOTUGRE for allowing me the opportunity to conduct this study within the boundaries of the Northern Tuli Game Reserve, assistance during the total aerial counts and financial contribution to the project. A special word of thanks to Mashatu Game Reserve for their continuous support in the project allowing me access to their land, accommodation and financial and logistical support from day one. To all the landowners and managers within the Northern Tuli Game Reserve, the Tuli Block Farms west of the Motloutse River, Mr. Knott and the Ambler-Smith family of Nottingham Estate in Zimbabwe, The Bristow family of Sentinel Ranch in Zimbabwe, Mr. Bernard van Lente of SANParks, Mr. Wilbert van Foort and Stefan Cilliers of SANParks for all their assistance. Many thanks to Digby and Vanessa Bristow for hosting me, while surveying within the Zimbabwean section. Many thanks to CESVI and Mr. Alan Sparrow for sharing their data with me. SANParks, the Department of Wildlife and National Parks, Botswana and the Wildlife Department, Zimbabwe for assistance in the project and the aerial counts conducted within the three countries. To my supervisor, Prof Wouter van Hoven and my Co-supervisor, Dr. Marion Garaï, i for their guidance and endless patience. My endless appreciation to Bruce Page for his guidance, support and assistance in all aspects of the project over the past years. To Pete and Jane Le Roux for all the help and support. Your insight and guidance was immeasurable. To all my friends, the Mashatu staff and rangers my sincere gratitude. To my family who helped and supported me through the years. ii THE SOCIAL STRUCTURE, DISTRIBUTION AND DEMOGRAPHIC STATUS OF THE AFRICAN ELEPHANT POPULATION IN THE CENTRAL LIMPOPO RIVER VALLEY OF BOTSWANA, ZIMBABWE AND SOUTH AFRICA By Sarah-Anne Jeanetta Selier Supervisor: Prof. W. van Hoven Co-Supervisor: Dr. M. Garaï Centre for Wildlife Management Faculty of Natural and Agricultural Sciences University of Pretoria Magister Scientiae (Wildlife Management) ABSTRACT The Central Limpopo River Valley elephant population is a cross border population on which very little scientific data pertaining to numbers, distribution and demographic status is available. The total range was determined using published literature, reports, postal questionnaires and interviews. Numbers and dry season distribution were determined by means of three total aerial counts in 2000, 2001 and 2004 of the sections of the total range in which elephants were reported. Totals of 1388, 1424 and 1339 were recorded with the highest numbers in all counts in the Botswana section of the study area. Four sub groups within the population were identified. Human settlements and the distribution of rivers and fencing appeared to be the major factors influencing distribution and movement. The population is highly mobile within the total range, and numbers fluctuate markedly in any given section, but numbers in the total range appear to have been increasing slowly at below 2% per annum and the range expanding slightly over the last 30 years. Additional range is being provided by the creation of a Trans Frontier Conservation Area. Movements were determined through ground observations within the study area and seem to follow the major rivers namely the Shashe, Ramokgwabane, Simukwe, Shashani, Tuli, Umzingwane and Limpopo rivers. The social and demographic status of the population was determined through ground observations as well as total aerial counts conducted within the Northern Tuli Game Reserve from 1976 to 2004. The study has iii shown that group sizes increase with an increase in rainfall (average mean group size of 56.524, SDE 77.388) and decrease during low rainfall periods (mean group size of 24.157, SDE 22.223). The age structure was determined from aerial photographs during August 2000 and showed a high percentage of adults and sub adults, with infants estimated at 3%. The approximate birth rate (1.5%) calculated for 2000 is balanced by an average natural mortality determined between 1999 and 2004 of 1.8%. The inter calf interval determined from known herds observed in the Northern Tuli Game Reserve was estimated at 3.94% and suggests that the long- term birth rate for the population should be higher than that for the year 2000. The difference between the combined natural and human induced mortality rates (~4%) and the birth rate suggested by the age structure and the inter calf interval (~6%) gives the ~2% long-term increase observed in the numbers. Human elephant interactions within the study area were determined through published literature and interviews with local residents. Elephants and humans interact in both a positive and negative manor and interactions are related to human land use practices within the area. Elephants were indicated as the major problem animal in farming areas, but the major draw card within tourism operations. Additional keywords: distribution, numbers, group sizes, Northern Tuli Game Reserve, Trans Frontier Conservation Area, range, mortality rate, birth rate, inter calf interval, rate of increase, age structure, human elephant conflict iv TABLE OF CONTENTS AKNOWLEDGEMENTS ........................................................................................................... i ABSTRACT ............................................................................................................................ iii CONTENTS ............................................................................................................................. v LIST OF TABLES ................................................................................................................... ix LIST OF FIGURES .................................................................................................................xi LIST OF APPENDICES ........................................................................................................ xiii THE SOCIAL STRUCTURE, DISTRIBUTION AND DEMOGRAPHIC STATUS OF THE AFRICAN ELEPHANT POPULATION IN THE CENTRAL LIMPOPO RIVER VALLEY OF BOTSWANA, ZIMBABWE AND SOUTH AFRICA INTRODUCTION...................................................................................................................... 1 BACKGROUND TO THE STUDY ........................................................................................... 1 AIMS AND OBJECTIVES........................................................................................................ 5 Objective................................................................................................................................. 5 Specific aims .......................................................................................................................... 5 REFERENCES......................................................................................................................... 7 THE STUDY AREA LOCATION .............................................................................................................................. 8 CLIMATE ................................................................................................................................. 8 GEOLOGY AND SOILS ........................................................................................................ 11 TOPOGRAPHY AND DRAINAGE......................................................................................... 13 VEGETATION........................................................................................................................ 15 Floodplains on alluvium ...................................................................................................... 17 Colophospermum mopane/Termimalia pruniodes rugged veld on basalt ..................... 20 Karoo sandstone landscape ............................................................................................... 22 FAUNA................................................................................................................................... 24 HISTORY ............................................................................................................................... 26 LAND TENURE,