ANALYSING AND MODELLING THE ECOLOGICAL REQUIREMENTS OF REPTILES AND LARGE ARACHNIDS: A STUDY OF THE LEEUSPRUIT PRIVATE NATURE RESERVE. BY PAUL SEBASTIAN RABIEGA Minor-Dissertation submitted in partial fulfilment of the requirement for the degree MASTER OF HUMANITIES In ENVIRONMENTAL MANAGEMENT In the Faculty of Humanities at the UNIVERSITY OF JOHANNESBURG Supervisor: Dr. Isaac T. Rampedi Co-supervisor: Dr. Francois Durand October 2013 Dedication This study is dedicated to all the people that have a deeper and fulfilling fascination in our indigenous reptile and large arachnids i Acknowledgements The following persons I owe my gratitude and sincere appreciation for all they have done to facilitate the completion of this study. To my mother, Bozena and brother, Patrick for the never ending field trips, patience, understanding and support they have offered whilst conducting this research. This research could not have been completed without your motivation. To my grandparents, Siegmund and Helena for their allowing me to pursue my ambitions in life and further education. To my late father, Andzej may you rest assured that I have made a success of my life. To my supervisor, Dr. Isaac Rampedi (Department of Geography, Environmental Management and Energy Studies, University of Johannesburg) for providing me the opportunity to conduct research in my chosen field and monitoring my progress with exceptional input to grant this research a success. To my co-supervisor, Dr. Francois Durand (Department of Zoology, University of Johannesburg) for his expertise and knowledgeable input in guiding and facilitating this research to grant it a meaningful and fruitful output. To Johan van Wyk (Environmental Scientist, Sasol Ltd.) for his agreement in accepting and facilitating the advancement of this research in the study area. To Japie Strydom and Sampie van der Merwe (Game rangers, Sasol Ltd. Nature Reserves) for their time spent in accommodating me in the study area and providing useful discussions. To Mariana van Wyk (Botanist) for her enthusiasm and time spent in the identification and processing of numerous plant species present in the study area. To Johan Marais (Herpetologist: African Snake Bite Institute/Reptile Ventures) for his expert advice and help in answering a series of questions. ii To Ian Engelbrecht (PhD Candidate: Researcher at the University of Pretoria) for his insight and help in scorpion taxonomy. To the National Research Foundation (NRF) for their financial contribution. iii Abstract Reptiles are internationally one of the least studied taxa compared to all other vertebrates, and even less is known about the large arachnids. This proves problematic as the environmental management of reptile and large arachnid species is generally neglected or only partially considered in environmental impact studies and conservation. Consequently, there is a considerable lack of knowledge on the ecological requirements (dietary and habitat requirements) of reptiles and invertebrates. Furthermore, the environmental management of reptiles and large arachnids in the Leeuspruit Private Nature Reserve is restricted as no data exists on the assemblage of these taxa in the study area. A model based approach was used to examine the ecology of species of reptiles and large arachnids (scorpions and baboon spiders) that were found in the Leeuspruit Private Nature Reserve during this study. The study proposes a baseline analysis between the species found in the study area and the suitability and availability of the ecological requirements necessary to their survival. The ecological requirements of each species were noted and utilised as the variable input categories in a scoring model developed for this study. Each species identified in the study area was allocated points from the scoring model based on favourable ecological requirements for that particular species. Field work was conducted in the Leeuspruit Private Nature Reserve in the northern Free State Province (March 2012 – March 2013) to do a survey on reptile and large arachnid diversity and to record the habitats in which they occur. A list of the reptiles and large arachnids found in the Leeuspruit Private Nature Reserve was compiled. One of the significant results which came to light during this study is that the diversity and abundance of reptiles and large arachnids are dependent on the availability and diversity of habitats with the necessary ecological requirements for those species. For example, the distribution of snake species was largely dependent on the abundance of amphibians and birds for food which coincided with a seasonal wetland in the study area; while rocks and detritus proved imperative to the seasonal functionality of the reptiles. iv During this study it was determined that 23 reptiles, four scorpion species and a baboon spider species occur in the study area. Fourteen of the reptile species found were not previously recorded from the Sasolburg 2627DD quarter degree grid cell map area; which constitutes a 61% increase of known reptile diversity in this area. The four scorpion species and one baboon spider found in the study area are all new records and the unexpected extensions of the geographical distribution ranges of a species of burrowing scorpion (Opistophthalmus glabrifrons) and a species of bark scorpion (Uroplectes triangulifer marshali) in the Free State Province were a key finding. The findings of this study facilitated a discussion on recommendations proposed to Sasol Ltd. on how to facilitate the environmental management of the Leeuspruit Private Nature Reserve in order to preserve the biodiversity and abundance of indigenous reptile and large arachnids. The new species records have been submitted to ReptileMAP, ScorpionMAP and SpiderMAP which are projects of the Animal Demography Unit of the University of Cape Town to improve the national indigenous reptile database. v TABLE OF CONTENTS CHAPTER 1: INTRODUCTION AND RESEARCH BACKGROUND 1 1.1. INTRODUCTION 1 1.2. ORGANISATION OF THE DISSERTATION 2 CHAPTER 2: STATEMENT OF THE RESEARCH PROBLEM 5 2.1. INTRODUCTION 5 2.2. RESEARCH PROBLEM STATEMENT 5 2.3. AIM OF THE STUDY 6 2.4. OBJECTIVES OF THE STUDY 6 2.5. LIMITATIONS OF THE STUDY 7 2.6. SCOPE OF THE STUDY 8 CHAPTER 3: DESCRIPTION OF THE STUDY AREA 10 3.1. INTRODUCTION 10 3.2. HISTORY OF THE STUDY AREA 10 3.3. LOCATION OF THE STUDY AREA 11 3.4. CLIMATE 13 3.4.1. Rainfall 13 3.4.2. Temperature 14 3.5. GEOLOGY AND SOILS 16 vi 3.6. HYDROLOGY 17 3.7. TOPOGRAPHY 17 3.8. VEGETATION 18 CHAPTER 4: LITERATURE REVIEW 21 4.1. INTRODUCTION 21 4.2. REPTILES AND LARGE ARACHNIDS POTENTIALLY FOUND IN THE LEEUSPRUIT PRIVATE NATURE RESERVE 21 4.2.1. Reptiles 23 4.2.1.1. Tortoises and terrapins 26 4.2.1.2. Snakes 26 4.2.1.3. Lizards 30 4.2.2. Large Arachnids 32 4.2.2.1. Baboon Spiders 33 4.2.2.2. Scorpions 34 4.3. REPTILE AND LARGE ARACHNID BIOLOGY 35 4.4. ALIEN INVADER RISKS 37 CHAPTER 5: RESEARCH METHODOLOGY 39 5.1. INTRODUCTION 39 5.2. DEVELOPMENT OF SPECIES INVENTORIES 39 5.3. FIELD WORK AND DATA CAPTURE 45 5.3.1. Primary Method 46 vii 5.3.2. Pitfall trap and funnel trap arrays 48 5.4. ECOLOGICAL REQUIREMENTS 54 5.5. THE SCORING MODEL 61 CHAPTER 6: RESULTS 65 6.1. INTRODUCTION 65 6.2. METHODOLOGICAL APPROACHES 65 6.3. SPECIES CONFIRMED TO OCCUR IN THE LEEUSPRUIT PRIVATE NATURE RESERVE 66 6.4. COMPARISON OF SPECIES ECOLOGICAL REQUIREMENTS 72 6.4.1. Species dietary requirements comparison 72 6.4.2. Species habitat requirements comparison 76 CHAPTER 7: DISCUSSION OF RESULTS 82 7.1. INTRODUCTION 82 7.2. SPECIES ABSENCE AND UNCERTAINTY 82 7.3. EXTENSION OF SPECIES DISTRIBUTION RANGES 87 7.3.1. Tread snake (Leptotyphlops sp.) 87 7.3.2. Scorpions (Opistophthalmus sp. and Uroplectes sp.) 88 7.4. BEHAVIOUR, ECOLOGY AND FIELD OBSERVATIONS 89 7.5. RECOMMENDATIONS 94 7.5.1. Vegetation litter 94 7.5.2. Fires 94 viii 7.5.3. Moribund termitaria 95 7.5.4. Amphibians and water quality 96 7.5.5. Rocks, stones and building rubble 96 7.5.6. Manhole 96 7.5.7. Human impacts 97 7.5.8. Environmental legislation 97 7.5.9. Further research 97 7.5.10. Push factors 98 CHAPTER 8: CONCLUSION 99 CHAPTER 9: REFERENCES 101 ix LIST OF FIGURES Figure 3.1: A pan occurring in the Leeuspruit Private Nature Reserve. 11 Figure 3.2: The location and boundary of the Leeuspruit Private Nature Reserve. 12 Figure 3.3: Mean monthly rainfall (mm) for the Leeuspruit Private Nature Reserve (Sasolburg). 14 Figure 3.4: Mean monthly maximum temperatures for the Leeuspruit Private Nature Reserve (Sasolburg). 15 Figure 3.5: Mean monthly minimum temperatures for the Leeuspruit Private Nature Reserve (Sasolburg). 15 Figure 3.6: Plant samples that were taxonomically identified. 19 Figure 4.1: Predation chart of snakes and their eggs. 25 Figure 4.2: Trachemys scripta elegans (Red-eared slider) are known to be persistent alien invaders. 38 Figure 5.1: Protective gear and equipment utilised in the capture of reptiles and large arachnids. 47 Figure 5.2: Overview array of pitfall traps and funnel traps. 49 Figure 5.3: Cross-section view of pitfall trap and funnel trap array. 50 Figure 5.4: Basic design of a funnel trap. 50 Figure 5.5: Equipment needed to construct pitfall trap and funnel trap arrays. 52 Figure 5.6: The manhole that serves as a permanent ‘pitfall trap’. 53 Figure 5.7: The proposed model based on dietary and habitat requirements. 63 Figure 6.1: Dietary requirements of all potential species found in the Leeuspruit x Private Nature Reserve. 74 Figure 6.2: Dietary requirements of species found to occur in the Leeuspruit Private Nature Reserve. 75 Figure 6.3: Habitat requirements of all potential species found in the Leeuspruit Private Nature Reserve.