Mapping the Spatial Configuration and Severity of Giraffe Skin Disease in Ruaha National Park, Tanzania
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MAPPING THE SPATIAL CONFIGURATION AND SEVERITY OF GIRAFFE SKIN DISEASE IN RUAHA NATIONAL PARK, TANZANIA By Arthur Bienvenu Muneza A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Fisheries and Wildlife – Master of Science 2016 ABSTRACT MAPPING THE SPATIAL CONFIGURATION AND SEVERITY OF GIRAFFE SKIN DISEASE IN RUAHA NATIONAL PARK, TANZANIA By Arthur Bienvenu Muneza Giraffe numbers, have dropped by about 40% in the last 20 years, making giraffes a species of conservation concern. In the same period of time, a skin disease has been observed in numerous giraffe populations across Africa. The disease, commonly referred to as giraffe skin disease (GSD), manifests as lesions, wrinkled skin, and encrustations that can affect the limbs, shoulder or neck of giraffes. Giraffe skin disease may hinder movement causing increased susceptibility to predation. In chapter 1, I reviewed GSD cases from literature reports and surveying efforts of individuals working with giraffes in the wild and in captivity in order to compile a database of known GSD cases. I detected variation in the manifestation, prevalence and severity of GSD in sub-Saharan Africa and giraffe populations in captivity. In chapter 2, I used photographic capture-recapture surveys via road-based transects in Tanzania’s Ruaha National Park to develop a database of spatially-explicit giraffe images. I used WildID to process these photos for individual identification and fitted spatial capture-recapture models to predict the spatial configuration of giraffe abundance and GSD prevalence within the study area. My results indicated that >86% of the giraffe population showed signs of GSD, which is the highest prevalence of the disease in Africa. With vast areas of Sub-Saharan Africa still without information on GSD, researching the prevalence and conservation impacts of this disease should be a priority. I also discuss the implications of this research for conservation of threatened species with an emphasis on disease ecology and vulnerability to predations, and more broadly, for wildlife conservation. ACKNOWLEDGEMENTS I am very grateful to the people who contributed to this research, whose support and input made this work possible and as unproblematic as possible. I would like to thank my academic supervisor Robert Montgomery for his mentorship, patience, and guidance to achieve my academic goals and embrace every challenge. I am very thankful to my graduate committee members Gary Roloff and Jerry Urquhart for their valuable input and feedback. I am also thankful to Amy Dickman, Julian Fennessy, Daniel Linden, and David Macdonald for lending their expertise in this study. Many thanks my colleagues in the RECaP laboratory who provided useful feedback to make this work easier and were a source of motivation. Generous financial support for this research was provided by the MasterCard Foundation Scholars Program at Michigan State University (MSU), RECaP Laboratory at MSU, the Giraffe Conservation Foundation, the Leiden Conservation Foundation, the American Society of Mammologists, and Roger Williams Zoo. I thank R. Glew, I. Kalumbu, and P. Croom among others for administration of the MCF Graduate Scholars Fellowship. I would like to thank S. Lipenga, M. Kimaro, N. Zuberi, A. Msago, J. Chambulila, U. Mgogo, G. Kimathi, R. Lipenga, S. Enock, G. Sedoyeka, B. Lawa, D. Bora, P. Rogers, and all the staff at Ruaha Carnivore Project and Ruaha Lion Guardians for their incredible support and participation in data collection, and making my time in Ruaha extremely enjoyable. I extend my gratitude to M. Brown, M. Castles, P. Clark, C. Pacho, P. Coppolillo, Chester Zoo, C. van Wessem (Paignton Zoo), P. Seeber, A. Ganswindt, C. Riehm, R. Van Beek (Oregon Zoo), and K. McQualter for contributing photos to this thesis. I also recognize the assistance provided by COSTECH, TANAPA and TAWIRI officials in making this research possible. iii Thank you Georgina Montgomery and Olivia Montgomery for being a permanent source of joy and encouragement during my time in East Lansing. I would like to thank my friends in the MasterCard Foundation Scholars Programme, in particular J. Vareta, A. Kakpo, C. Latona, E. Ansah, F. Uwimbabazi, J. Awadu, R. Kaihula, C. Gapare, among others, who offered different perspectives and for their motivation. I am grateful to the Applied Forest and Wildlife Ecology Lab at MSU for their company and advice. I would like thank Tom and Kathy Leiden, and the Adams Family for their support and encouragement. Lastly, I would like to thank my father Félicien Murego and two brothers, Felix Kwizera and Pierre Muhoza for bringing out the best in me with their guidance and motivation. iv TABLE OF CONTENTS LIST OF TABLES ......................................................................................................................... vi LIST OF FIGURES ...................................................................................................................... vii INTRODUCTION .......................................................................................................................... 1 REFERENCES ............................................................................................................................ 3 CHAPTER 1 ................................................................................................................................... 5 REGIONAL VARIATION OF THE MANIFESTATION, PREVALENCE, AND SEVERITY OF GIRAFFE SKIN DISEASE: A REVIEW OF AN EMERGING DISEASE IN WILD AND CAPTIVE GIRAFFE POPULATIONS .......................................................................................... 5 Abstract ....................................................................................................................................... 5 1.1. Introduction ...................................................................................................................... 6 1.2. Methods ............................................................................................................................ 9 1.3. Results ............................................................................................................................ 10 1.3.1. Review of skin diseases in giraffe populations ....................................................... 10 1.3.2. Variation in the anatomical location of GSD lesions.............................................. 11 1.3.3. Spatial variation in prevalence of GSD .................................................................. 12 1.3.4. Spatial variation in severity of GSD ....................................................................... 14 1.4. Discussion ...................................................................................................................... 15 Acknowledgements ................................................................................................................... 23 APPENDIX ............................................................................................................................... 24 REFERENCES .......................................................................................................................... 39 CHAPTER 2 ................................................................................................................................. 45 EXAMINING DISEASE PREVALENCE FOR SPECIES OF CONSERVATION CONCERN USING NON-INVASIVE SPATIAL CAPTURE-RECAPTURE TECHNIQUES ..................... 45 Abstract ..................................................................................................................................... 45 2.1. Introduction .................................................................................................................... 46 2.2. Methods .......................................................................................................................... 49 2.2.1. Study area .................................................................................................................... 49 2.2.2. Vehicle-based photographic surveys ........................................................................... 50 2.2.3. Spatial Capture Recapture ........................................................................................... 51 2.3. Results ............................................................................................................................ 54 2.4. Discussion ...................................................................................................................... 56 Acknowledgements ................................................................................................................... 60 APPENDIX ............................................................................................................................... 61 REFERENCES .......................................................................................................................... 67 CONCLUSION ............................................................................................................................. 73 REFERENCES .......................................................................................................................... 75 v LIST OF TABLES Table 1.1. List of sources that reference descriptions of skin diseases in populations of wild giraffe…………………………………………………………………………………25 Table 1.2. Areas where skin disorders have been observed in giraffe subspecies.