Mapping and Modelling the Population and Habitat of the Roan Antelope (Hippotragus equinus langheldi) in Ruma National Park, Kenya Johnstone Kithiki Kimanzi A Thesis Submitted for the Degree of Doctor of Philosophy at Newcastle University School of Biology Newcastle University Newcastle upon Tyne NE1 7RU January 2011 i Declaration No portion of the work presented in this thesis has been submitted in support of an application for another degree or qualification of this or any other university or other institute of learning i Acknowledgements This thesis could not have been completed without the help and support of many People and institutions. First of all, I would like to thank my supervisors, Roy Sanderson and Stephen Rushton, for their invaluable advice, guidance, and statistical and computer support throughout the research period. Without your precise supervision and prompt feedback, completion of this thesis would have taken longer than three years. I am grateful to Peter Lurz for introducing me to RANGES package and Mark Shirley for induction in applying R package. I thank Louis Goffe for support in GIS techniques. I thank my colleague, Andrew Close, for being an older brother to show me the way when I got stuck. I acknowledge the Commonwealth Scholarship Commission for funding this research fully. I thank my employer, Moi University, for granting me adequate study leave. Kenya Wildlife Service (KWS) granted permission for carrying out this research in Ruma National Park. The Regional Centre for Mapping of Resources for Development (RCMRD) and Kenya Soil Survey provided data for this study. Fieldwork was made possible by the cooperation and hosting of the Ruma National Park management. Special thanks go to the Acting Park Warden, David Kones, for providing secure accommodation within the park and ensuring comfortable settling down. Thanks also go to park research assistant, George Ouma, for induction in the park and its environs. Special thanks go to my research assistant, Alex Kyalo, who worked tirelessly during data collection. I thank the team of park rangers who provided adequate security during data collection. I express my heartfelt thanks to my wife, Jennifer, my son, Gabriel, and my daughter, Favour for your tremendous love, patience and encouragement. Jennifer, I sincerely thank you for being a true helper, your competence in taking charge of the family during my long periods of absence and for working tirelessly to supplement the ii family finances. Gabriel, your superb progress in your studies without my adequate attention kept me going. Favour, your gorgeous smile gave me inner strength especially when things were tough. My profound thanks goes to my mum, Emmah, for her unfathomable quest for knowledge and strict upbringing, that has brought me this far. Thanks to members of the Newcastle Apostolic Church for your encouragement, love and prayers. I thank Pastor John for the inspiring biblical teachings. Your teaching on discerning divine helpers greatly boosted my success. Above all, I thank the Lord God Almighty who is my source of strength and for providing everything. iii Abstract Wildlife-based tourism, which is Kenya’s second largest economic sector, is threatened by the risk of extinction of many wildlife species in the country. The endemic roan antelope (Hippotragus equinus langheldi) now only survives in Ruma National Park (RNP) where its population has been declining continuously since 1976. This thesis investigates the roan’s habitat use and selection, causes of population decline and population viability in RNP with the aim of recommending scientifically-based management interventions for population recovery and sustainable conservation. Roan movement patterns and habitat use were investigated using 4 home range estimation techniques. Habitat selection was studied at multi-spatial scales using compositional analysis, logistic regression, and information-theoretic (IT) and multi-model inference (MMI) techniques. Data for this study consisted of population estimates for roans and other grazers, Landsat images, soil maps, digital terrain data, rainfall records, snare distribution records, and roan ground tracking data. Identification of causes of population decline was carried out using both multivariate and univariate techniques. A generic population viability analysis (PVA) package was used to (i) estimate the likelihood of roan extinction under various management options; and (2) rank the management alternatives for roan population recovery. All 4 home range estimators are useful in characterizing different aspects of the roan home range, but overall the local convex hull method produced the most realistic home ranges. The three habitat selection methods yielded similar results but the IT techniques demonstrated superior qualities as they identified important habitat variables and produced the most accurate model predictions. MMI averaged models coupled with GIS data developed very informative habitat suitability and poaching risk maps. Analysis of habitat selection indicated different usage in iv seasons and spatial scales depending on water availability, habitat composition and burned status, and distribution of eco-geographical features. High adult mortality due to poaching with snares was identified as the main cause of roan population decline. Other important factors included habitat change and rainfall variability with its associated droughts and floods. PVA showed that under the current conditions, the roan population cannot persist more than 3 decades. Several anti-poaching and prioritized management interventions to curb poaching and promote population recovery are described. v Table of Contents Declaration ........................................................................................................................... i Acknowledgements ............................................................................................................. ii Abstract .............................................................................................................................. iv Table of Contents ............................................................................................................... vi CHAPTER 1: General Introduction .................................................................................... 2 1.1 The roan antelope: Description, biology, population status and distribution .......... 2 1.1.1 Physical description.............................................................................................. 2 1.1.2 The roan biology .................................................................................................. 2 1.1.3 Population status and distribution in Africa ......................................................... 4 1.2 The rationale of the research .................................................................................... 7 1.3 Research objectives ................................................................................................ 12 1.4 Outline of thesis ..................................................................................................... 13 1.5 Description of the study area ................................................................................. 16 CHAPTER 2: Vegetation mapping and herbivore population dynamics in Ruma National park (RNP) ........................................................................................................................ 21 2.1 Introduction ............................................................................................................ 21 2.1.1 Research objectives ............................................................................................ 27 2.1.2 Hypotheses and predictions ............................................................................... 27 2.2 Methods.................................................................................................................. 28 2.2.1 Data collection.................................................................................................... 28 2.2.1.1 Herbivore population census .......................................................................... 28 2.2.1.2 Vegetation mapping ........................................................................................ 30 2.2.1.2.1 Image pre-processing ...................................................................................... 31 2.2.1.2.2 Vegetation ground truthing ............................................................................. 34 2.2.1.2.3 Vegetation changes ............................................................................................ 38 2.2.1.3 Rainfall measurements ................................................................................... 38 vi 2.2.2 Statistical data analysis and modelling .............................................................. 39 2.2.2.1 Vegetation map accuracy assessment ............................................................. 40 2.2.2.2 Multivariate techniques .................................................................................. 41 2.2.2.3 Generalized linear models (GLM) .................................................................. 42 2.2.2.4 Model assessment ........................................................................................... 43 2.3 Results .................................................................................................................... 44 2.3.1