Kent Academic Repository Full text document (pdf) Citation for published version Nash, Darryn James (2017) An Assessment of Mitigation Translocations for Reptiles at Development Sites. Doctor of Philosophy (PhD) thesis, University of Kent, University of Kent. DOI Link to record in KAR https://kar.kent.ac.uk/65820/ Document Version UNSPECIFIED Copyright & reuse Content in the Kent Academic Repository is made available for research purposes. Unless otherwise stated all content is protected by copyright and in the absence of an open licence (eg Creative Commons), permissions for further reuse of content should be sought from the publisher, author or other copyright holder. Versions of research The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record. Enquiries For any further enquiries regarding the licence status of this document, please contact: [email protected] If you believe this document infringes copyright then please contact the KAR admin team with the take-down information provided at http://kar.kent.ac.uk/contact.html An Assessment of Mitigation Translocations for Reptiles at Development Sites Darryn James Nash Thesis submitted for the degree of Doctor of Philosophy August 2017 The Durrell Institute of Conservation and Ecology University of Kent, Canterbury, CT2 7NR, England Abstract All native reptile species are protected against harm through their inclusion on UK legislation. With the exception of two species, this protection does not extend to reptile habitat. As a result, reptiles are frequently subject to mitigation translocations to facilitate the development of land. However, there are few published studies of the effects of mitigation translocation on reptile populations and whether such translocations are effective conservation interventions. The effectiveness of translocation was tested through a combination of: 1) field surveys of sites subject to mitigation across England and Wales; 2) the radio tracking of translocated adders; 3) the monitoring of a population of slow-worms at site where they were released 20 years ago; and 4) a penning experiment to test whether viviparous lizards attempt to disperse from the release site. Very few translocated reptiles were encountered during the monitoring of release sites. This paucity of recaptures is either due to post-release mortality, imperfect detection or dispersal. Translocated male adders dispersed farther and had larger home range sizes than resident conspecifics. Some male adders undertook large unidirectional migrations back to the donor site crossing areas of unsuitable habitat as they did so. A population of slow-worms persisted at an isolated site two decades after translocation, albeit in relatively small numbers. Body condition improved over 20 years and the population resumed breeding and recruitment. The temporary penning of viviparous lizards was effective in preventing post-release dispersal and resulted in an increase in recapture rates of greater than 16 times when compared to unpenned viviparous lizard populations. The fact that no lizards were recaptured in the unpenned areas provides strong evidence for the effect of post-release dispersal. Although, mitigation translocations may prevent the immediate death of animals that would otherwise i be destroyed with their habitat, there is little evidence that they are compensating for the loss of populations on a broad scale. Keywords: reptiles; mitigation; development; receptor site; dispersal; radio telemetry; penning ii Acknowledgements I have been extremely fortunate to have been surrounded by an understanding, supportive and encouraging community of people during this project. My heartfelt thanks are extended to all those that have contributed technically, emotionally or financially towards this study. Without your support, I very much doubt that this study would have been possible. I would like to thank my supervisor, Professor Richard Griffiths, for his unwavering support throughout this project. Richard’s uncanny ability to pick you up and enthuse you after setbacks, disappointment and frustration has been an invaluable source of inspiration for me. Thanks go to my good friend David Price who has been a major source of support for this project. David has secured study sites, assisted with field work and spent many, many hours listening to me talk about this project. I would like to thank Dr Todd Lewis who has shown endless support and encouragement since the very inception of this project. Over the past 10 years, Todd has provided invaluable guidance and is almost certainly responsible for stimulating my love of reptiles and rum. Without the contribution of ecological consultants this project would certainly not have been possible. I would like to thank all those at Sylvan Ecology and Herpetologic for supplying study sites and Neil Humphries of Celtic Energy and Ryan Mellor of AECOM for their financial support. Finally, I would like to thank my extremely patient wife and best friend, Ele, without whose love and unwavering support I would not have been able to complete this achievement. iii Table of Contents Page Abstract i Acknowledgements iii Table of Contents iv List of Figures vii List of Tables viii Chapters 1.0 General Introduction 1 1.1 Global Declines in Wildlife 1 1.2 Global Reptile Declines 3 1.3 Reptile Status in Europe 4 1.3.1 European Protection 6 1.3.2 European Union Protection 6 1.4 The Situation in the UK 8 1.4.1 UK Legal Protection 8 1.4.2 British Reptile Fauna 11 1.4.3 Threats 14 1.5 Reptiles and Development 16 1.5.1 Planning Considerations 16 1.5.2 Mitigation 17 1.5.3 Translocation 19 1.5.4 Evidence of Successful Translocations 20 1.6 Aims of this Study 20 1.7 References 22 2.0 Monitoring the Fate of Reptiles Translocated from Development Sites 31 2.1 Summary 30 2.2 Introduction 33 2.2.1 Aims and Objectives 36 2.3 Methods 37 2.3.1 Site Selection Protocol 37 iv 2.3.2 Study Sites 38 2.3.3 Field Survey Protocol 45 2.3.4 Data Analysis 47 2.4 Results 48 2.5 Discussion 52 2.5.1 Future Studies 59 2.6 References 60 3.0 Spatial Ecology of Translocated Adders 67 3.1 Summary 67 3.2 Introduction 68 3.2.1 Objectives 73 3.3 Methods 74 3.3.1 Study Site 74 3.3.2 Experimental Design 76 3.3.3 Data Analysis 80 3.4 Results 83 3.4.1 Movements 83 3.4.2 Range Analyses 88 3.4.3 Detection 90 3.4.5 Habitats 90 3.4.6 2015 Survey 91 3.5 Discussion 92 3.5.1 Distances 93 3.5.2 Ranges 95 3.5.3 Detection 97 3.5.4 Implications of Short vs. Long-distance Translocations 98 3.5.5 Future Studies 101 4.0 Status of a Slow-worm Population 20 Years After Translocation 109 4.1 Summary 109 4.2 Introduction 110 4.2.1 Objectives 112 4.3 Methods 113 4.3.1 Bus Company Island 113 v 4.3.2 Field Surveys 114 4.3.3 Data Analysis 116 4.4 Results 120 4.4.1 Encounters 120 4.4.2 Huggins RD Model 122 4.4.3 Body Condition Indices 124 4.5 Discussion 127 4.5.1 Conclusions 133 4.6 References 134 5.0 Can Penning Improve the Outcome of Reptile Translocations? 138 5.1 Summary 138 5.2 Introduction 139 5.2.1 Objectives 141 5.3 Methods 143 5.3.1 Donor Site 143 5.3.2 Release Site 143 5.3.3 Translocation 146 5.3.4 Monitoring 148 5.3.5 Data Analysis 148 5.4 Results 152 5.4.1 Recaptures 152 5.4.2 Encounter Rates 152 5.4.3 CJS Analysis 154 5.4.4 Population-level Morphometrics 158 5.4.5 Population Demographics 158 5.5 Discussion 159 5.5.1 Conclusions 162 5.5.2 Future Studies 163 5.6 References 165 6.0 Conclusions 170 6.1 Concluding Remarks 173 6.1 Future Studies 174 6.2 References 176 vi Appendices A: Request for Study Sites 179 B: Background Information and Protocol 180 C: Huggins RD Model Selection for BCI 186 D: CJS Model Selection for Penned Lizards 187 E: CJS Model Selection for Unpenned Lizards 188 F: Open models for Capture data 189 List of Figures Figure 2.1 Recaptures Scatter Graph 50 Figure 2.2 Recaptures by Species 51 Figure 3.1 Site Plan 72 Figure 3.2 Site Plan with Development Layout and Proposed Translocation 75 Figure 3.3 Radio Tag Attachment 79 Figure 3.4 Male Adder Movements 86 Figure 3.5 A comparison of mean ranges 89 Figure 3.6 A depiction of core ranges 89 Figure 4.1 Habitat map of BCI 113 Figure 4.2 Morphometric data collection method 115 Figure 4.3 Re-identification of slow-worms (labials) 116 Figure 4.3 Re-identification of slow-worms (cranials) 120 Figure 4.5 Encounter frequency by month 121 Figure 4.6 Histogram of encounter frequency 122 Figure 5.1 Site Plan 144 Figure 5.2 Experimental Design 145 Figure 5.3 Fencing Specifications 146 Figure 5.4 Capture histories by area 154 Figure 5.5 Capture frequency by area 156 vii List of Tables Table 1.1 Current Guidance for assessing reptiles 17 Table 2.1 Summary of Study Sites 45 Table 2.2 Summary of Recapture Data 49 Table 3.1 Comparative Mortality Rates of Translocated Snakes 70 Table 3.2 Comparison of Long and Short-distance Translocations 72 Table 3.3 Adder Morphometrics (April) 83 Table 3.4 Adder Morphometrics (August) 85 Table 3.5 Adder Movements Summary 85 Table 3.6 Adder Range Analysis 87 Table 3.7 Adder Detection Rates 90 Table 3.8 Adder Habitat Selection 90 Table 4.1 Encounter Summary 120 Table 4.2 Capture History 121 Table 4.3: Huggins RD Model Selection 123 Table 4.4: Estimates of Survival and Detectability 123 Table 4.5 Abundance Estimates 124 Table 4.6 Condition Indices 125 Table 5.1 Translocation Data 147 Table 5.2 Encounter Data 152 Table 5.3 Summary of Capture Data 153 Table 5.4 CJS Model Selection 155 Table 5.5 Survival and Detection Rates 156 Table 5.6 Population Demographics 158 viii 1.0 Introduction 1.1 Global Declines in Wildlife The Chinese Curse “May you live in interesting times” Anonymous Human activities are having an extremely profound effect on the world.