Predicting reptile species distributions and biogeographic patterns within Kruger National Park Jody Michael Barends University of the Western Cape, Department of Biodiversity and Conservation Biology, Private, bag X 17, Bellville, 7535, South Africa. A thesis submitted in fulfilment of the requirements for the degree of Magister Scientiae in the Department of Biodiversity and Conservation Biology, Faculty of Science, University of the Western Cape Supervisor: Dr. Bryan Maritz October 2018 i http://etd.uwc.ac.za/ Predicting reptile species distributions and biogeographic patterns within Kruger National Park Jody Michael Barends Keywords Biodiversity monitoring; Biogeography; Data bias; Geographic information systems (GIS); Kruger National Park; MaxEnt; Reptile fauna, SANParks; Species distribution modelling; Thresholds of potential concern. ii http://etd.uwc.ac.za/ Abstract Predicting reptile species distributions and biogeographic patterns within Kruger National Park J.M Barends MSc. Thesis, Department of Biodiversity and Conservation Biology, University of the Western Cape. Knowledge of global reptile ecology is limited and there remains much to understand in terms of detailed reptile species information, including that of their distributions. In South Africa, despite being one of SANParks best-studied reserves, surprisingly little is known about the distributions and spatial ecology of reptiles within Kruger National Park (KNP). Management within KNP follows a strategic adaptive management strategy which monitors the statuses of animals using species or group specific indicators. Indicators are given predetermined upper and lower ranges of acceptable fluctuation before actions are taken. These ranges are referred to as thresholds of potential concern (TPCs), and for reptiles these are based on changes to their distributions across the landscape of KNP. An apparent lack of high-quality reptile distribution data inhibits the effective monitoring of the statuses of these animals within KNP, which in turn limits management and conservation options. In this study, I use several methods to quantify available reptile occurrence data which formed the foundations for predicting the distributions of these species across KNP by means of species distribution modelling, with a view to gaining novel insight into reptile assemblage structure across the landscape of KNP. iii http://etd.uwc.ac.za/ I collated 7118 locality records representing 127 reptile species occurring within KNP. In quantifying these, I effectively performed a gap analysis of KNP and found that large areas of the park were poorly-sampled, with nearly 68 % of all records occurring within 2 km of infrastructure. Despite challenges relating to spatial scale and data bias, using an ecological niche modelling approach I predicted the geographical distributions of 119 reptile species across KNP at a resolution of 1 km x 1 km. I used these distributions to infer species’ presence or absence at any given 1 km x 1 km grid cell across KNP and to subsequently quantify assemblage membership via hierarchical cluster analyses. I predicted that at least nine taxonomically distinct, spatially-segregated reptile assemblages are present within KNP, with each appearing to be correlated with changes in landscape features across the park. My work has identified important gaps in our understanding of the distributions of reptiles in KNP that will drive future sampling efforts. Moreover, my modelled predictions offer multiple testable hypotheses in terms of species’ presences and absences that will direct future research efforts in KNP, and potentially aid in the monitoring of reptiles more generally across protected areas within South Africa. iv http://etd.uwc.ac.za/ Declaration I declare that “Predicting reptile species distributions and biogeographic patterns within Kruger National Park” is my own work, that it has not been submitted for any degree or examination at any university, and that all sources I have used or quoted have been indicated and acknowledged by complete references. Full name: Jody Michael Barends Date: October 2018 Signature: ………………………………………. v http://etd.uwc.ac.za/ Acknowledgments Special thanks go to Bryan Maritz, Robin Maritz, Donovan Tye, Graham Alexander, and all others involved in the Reptile Diversity in African Savannas (RDAS) field course. This includes UWC students Ielhaam Bassier, Riaaz Mohamed, and Silindokuhle Tokota, as well as several students from University of Mpumulanga and University of Venda who assisted me with field sampling. I would like to thank Herpetological Conservation International (HCI), Nsasani Trust, Organisation for Tropical Studies (OTS), African Snakebite Institute, and Comair Limited for their funding and donations. The efforts of all involved allowed me to complete a critical component of my project and this was greatly appreciated. I would like to thank my colleagues within the Maritz lab who assisted me throughout the duration of this project. Their support, discussions, and friendships have greatly aided in the completion of this thesis. To my family and friends, thank you for providing a constant stream of support and encouragement. A special thank you goes to Ielhaam Bassier for always being there for me, academically and otherwise, without whom the enjoyment of my time working on this project would have been significantly less. I would also like to acknowledge Darren Petersen, Guin Zambatis, the Ditsong Museum, OTS, and the Animal Demography Unit for providing me with reptile occurrence data. To Bryan Maritz, your guidance and supervision has been consistently provided to me at the highest degree possible. All of your efforts and contributions towards my academic career and experiences have been appreciated beyond measure. Lastly, thank you to those who provided funding towards the completion of this project. This includes the NRF, Ada and Bertie Levenstein foundation, and Merseta. Through the combined contributions of these organisations my financial expenses were covered which allowed me to focus all of my efforts on the successful completion of this thesis. vi http://etd.uwc.ac.za/ Contents Title page ................................................................................................................................................ i Keywords ............................................................................................................................................... ii Abstract ................................................................................................................................................. iii Declaration............................................................................................................................................. v Acknowledgments ................................................................................................................................ vi Contents ............................................................................................................................................... vii List of Tables ......................................................................................................................................... x List of Figures ....................................................................................................................................... xi List of Appendices .............................................................................................................................. xiii Preface ................................................................................................................................................. xiv Chapter 1: General introduction ......................................................................................................... 1 1.1 Biodiversity loss and its management in South Africa ................................................................. 1 1.2 Reptile monitoring and TPCs ........................................................................................................ 2 1.3 Problem statement ......................................................................................................................... 3 1.4 Study area...................................................................................................................................... 3 1.5 Approach ....................................................................................................................................... 5 1.5.1 Data: ....................................................................................................................................... 5 1.5.2 Spatial scale: .......................................................................................................................... 5 1.5.3 Chapter focus: ........................................................................................................................ 6 1.6 Major limitations ........................................................................................................................... 7 Chapter 2: A gap analysis of KNP reptile occurrence data .............................................................. 9 2.1 Introduction ................................................................................................................................... 9 2.2 Methods......................................................................................................................................
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