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A STANDARDISED PROTOCOL FOR ROADKILL DETECTION AND THE DETERMINANTS OF ROADKILL IN THE GREATER MAPUNGUBWE TRANSFRONTEIR CONSERVATION AREA, LIMPOPO PROVINCE, SOUTH AFRICA A thesis submitted in fulfillment of the requirements for the degree of MASTER OF SCIENCE of RHODES UNIVERSITY by WENDY JANE COLLINSON January 2013 DEDICATION This thesis is dedicated to Nairobi, Kenya, 21.08.2004, a day that gave me courage, And Nelson. ABSTRACT Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 h ours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h-1) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. i Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity. ii TABLE OF CONTENTS i ABSTRACT TABLE OF CONTENTS iii ACKNOWLEDGEMENTS vii CHAPTER 1 1 INTRODUCTION 1. The history and development of roads 2 2. The status of roads in South Africa 3 3. The impact of roads on wildlife 4 4. Aims 8 CHAPTER 2 9 DESCRIPTION OF THE STUDY SITE 1. Description and history of the study site 10 2. Topography and geology 14 3. Climate 17 4. Flora 20 5. Fauna 21 6. Site description 23 iii CHAPTER 3 DETECTING FLATTENED FAUNA: designing a standardised protocol for 26 the detection of roadkill 1. Introduction 27 2. Materials and methods 30 3. Results 41 4. Discussion 50 5. Conclusion 60 CHAPTER 4 HIT AND RUN: the determinants of roadkill in the Greater Mapungubwe 61 Transfrontier Conservation Area (GMTFCA), Limpopo Province, South Africa. 1. Introduction 62 2. Materials and methods 72 3. Results 96 4. Discussion 122 5. Conclusion 139 CHAPTER 5 141 THE ROAD AHEAD: strategies for the roadkill mitigation in South Africa 1. The road ahead 142 2. Factors affecting roadkill rates in the GMTFCA and strategies for South Africa 143 3. Concluding remarks 157 iv REFERENCES 160 APPENDIX 193 APPENDIX A A summary of previous roadkill studies (from peer-reviewed published journals) 194 comparing sample methods used to detect roadkill. APPENDIX B The vertebrate roadkill species detected over three ecological seasons on the 100 km section of paved road and the 20 km section of unpaved road in the 200 GMTFCA, South Africa APPENDIX C Caprimulgidae roadkill detected over three ecological seasons on the 100 km section of paved road and the 20 km section of unpaved road in the GMTFCA, 208 South Africa. APPENDIX D The live vertebrate species observed during the roadkill transects either on the road verge or crossing the road over three ecological seasons on the 100 km 211 section of paved road in the GMTFCA, South Africa. APPENDIX E The live vertebrate species observed during the roadkill transects either on the road verge or crossing the road over three ecological seasons on the 100 km 214 section of paved road in the GMTFCA, South Africa. APPENDIX F A series of vegetation maps illustrating the location of roadkill detected for 216 each vertebrate group in each of the three ecological seasons on the 100 km paved road and 20 km unpaved road in the GMTCA, South Africa. v APPENDIX G A series of vegetation maps illustrating the location of the top roadkill species detected for each vertebrate group across the three ecological seasons on the 221 100 km paved road and 20 km unpaved road in the GMTCA, South Africa. APPENDIX H Roadkill data collection sheet 229 vi ACKNOWLEDGMENTS The contributions of the following individuals and organisations during the period of my study are gratefully acknowledged: My employers, the Endangered Wildlife Trust (EWT), and their unwavering support in championing such a stimulating and exciting project that has grown into something that will ‘make a difference’. My supervisors, Dr Daniel Parker, Prof. Ric Bernard, Dr Harriet Davies‐ Mostert and Prof. Brian Reilly, for their persistent enthusiasm, constructive criticism and advice. Dan, in particular, for his unlimited patience and ‘beaver- like’ efficiency at wading through my many drafts. Bridgestone SA for extensive financial and logistical assistance. De Beers Consolidated Mines, E. Oppenheimer & Son, and Mopane Bush Lodge, for their logistical support and the opportunity to work in such an incredible part of South Africa, in particular Warwick Davies-Mostert, Duncan MacFadyen, Paul Hatty and Andrew Rae. Ian Rochat at VehicleCounts.com, for the donated traffic counter and road tubes. Ian Crouchley, for ‘coming to the party’. May you one day return! Global Vision International (GVI), for their assistance with the speed trials, in particular Anka Bedetti and Brie Sloggett (a.k.a. the puppies). Their deep love of the Gypsy Kings (Bang, Bang, Bang) is unnerving, yet I couldn’t have asked for better partners to drive with. Craig Beech at Peace Parks Foundation (PPF) and their GIS section for the supply and use of GIS data of the GMTFCA, and Armand du Preez Kok, for assistance with the GIS maps. Duncan MacFadyen, Ian Little, Andre Botha, Sean Thomas, Jeanne Tarrant, Michael Cunningham, Dan Parker, Ric Bernard, Vince Egan, Armand du Preez Kok, Andre de Kok and Andrew Rae for assistance with species identification of roadkill that was ‘very’ flattened. vii Dr Charlene Bissett, Carline van Vliet, Dr Kim Clube, David Collinson and Dr Lyn Haynes for reviewing chapters. Peter Bradford, Katherine Potgieter, Rox Brummer, John Power and Harriet Davies-Mostert, for opening my eyes to African wildlife and being such inspirational mentors; Pete, for providing me with the opportunity to go ‘beyond’ GVI, Kath, for the endless hours with the African wild dogs, and Dozer the Landy, Rox, for introducing me to the monotony of spoor counts, that would develop my endurance for the roadkill transects, John (the legend), for showing me how not to take everything so seriously, and Harriet, for believing in me from the beginning when I pounded on EWT’s door in 2006. Susan Miller, Carline van Vliet, Bianca Englebrecht, Galagos Wildlife Conservation and the Venetia Limpopo Nature Reserve staff for the countless favours they have done to help me bring this thesis to completion. Rox, Morné, Leila and Robbie Brummer and Mary Malisao, for providing endless support during the transects. Barclay, my co-pilot! Andrew, Moira, Mike, Angie, Jessie, and Gordie Rae, for providing me with a proper home and inviting me into their family. Paul and Rosemary Hatty, for the opportunity to live and work in such a beautiful place and for the 4-course meals at the lodge I was allowed to parasitize. To my dear friends in the GMTFCA who have provided more than a few wonderful sundowners. You have always been there for me, and helped motivate me through all the tough times. I would not be where I am today if it were not for you all. And finally I owe an enormous debt of gratitude to my family for their constant encouragement, love and support and believing in me.