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Kent Academic Repository Full text document (pdf) Citation for published version Ward, Robert John (2017) Status and conservation of the grass snake in Jersey. Doctor of Philosophy (PhD) thesis, University of Kent,. DOI Link to record in KAR http://kar.kent.ac.uk/65819/ 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 Status and conservation of the grass snake in Jersey Robert John Ward Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Canterbury, Kent CT2 7NR, UK Thesis submitted for the degree of Doctor of Philosophy in Biodiversity Management, September 2017 Word count: 31,390 Status and conservation of the grass snake in Jersey Robert John Ward Supervised by Professor Richard A. Griffiths Professor Jim J. Groombridge Dr John W. Wilkinson Ms Nina Cornish I “There is no fundamental distinction to be made between the extinction of a local population and the extinction of a species other than that the species becomes extinct with the extinction of the last local population” (Andrewartha and Birch, 1954, p. 665) II Acknowledgements Firstly I must thank my supervisors Richard Griffiths, Jim Groombridge, John Wilkinson and Nina Cornish for selecting me for this project, and their unwavering support and guidance over the last four years. I have been extremely lucky to have such an excellent supervision panel. This study was only possible thanks to support and funding from the States of Jersey Department of the Environment. I am thankful to the whole Natural Environment team, and to the States rangers (especially Keiran) who provided support in the field. Denise McGowan was instrumental in helping me get my bearings on the island and my capoeira família provided me with an outlet that prevented any snake (or lack thereof) madness. Perhaps most importantly I thank my dedicated volunteers; I am confident for the future of Jersey’s natural environment knowing those who are entrusted with, and enthused by, its conservation. I must highlight particularly the work of Krissy Le Feuvre, my most trusted volunteer and a driving force all of her own. I am indebted to the many landowners that allowed me access to their land; the National Trust for Jersey, the States of Jersey, Jersey Water, La Moye Golf Course, Les Ormes Golf Course, Les Mielles Golf Course, Jersey Royal Golf Course, Creepy Valley activity centre and others. Further support was given by the Durrell Institute of Conservation and Ecology, Durrell Wildlife Conservation Trust, Amphibian and Reptile Conservation, the British Herpetological Society, the Joint Nature Conservation Committee, Jersey Amphibian and Reptile Group, Jersey Conservation Volunteers, Jersey Biodiversity Centre, States of Jersey Meteorological Department, Jersey Ecology Fund, Jersey Countryside Enhancement Scheme, Amphibian and Reptile Groups of the UK, Harsco Jersey, III Action for Wildlife Jersey, the Insurance Corporation of the Channel Islands, the Royal Bank of Canada (Jersey) and the Natural History Museum, London. The Jersey public also deserve a special mention for being friendly and welcoming, and for the wealth of records that they submitted via the Think Grass Snake campaign. To my fellow DICE / SAC postgraduate students - the diverse bedrock of a thoroughly enjoyable research environment, and a group of people I am privileged to call my friends. Sometimes a source of support, often a source of procrastination. Perhaps the most missed aspect of PhD life will be our office environment, and I must particularly thank Gail Austen, Tristan Pett, Andrew Buxton, Debbie Fogell, Izabela Barata, Janna Steadman, Jim Labisko, Hazel Jackson, Moacir Tinôco and Lydia Tiller for their support and friendship. Thank you particularly to my lab mates for sharing the good and the bad times, and for your continued support and advice. Both Chris Durrant and Carolin Kindler also provided useful discussion and comments on molecular work for which I am grateful. Special thanks are needed for my internal and external examiners. Your comments and contributions are greatly appreciated. To my non-university friends who may have at times wondered if I was still on this planet, and I am sure regularly unaware of what county or country I was in. Your continued friendship and support despite my absenteeism in life demonstrate what true friendship is. Finally, to my fiancée Lisa and to my family for your eternal support; I can never repay what you have given me. It would not have been possible without you. Thank you. IV Author’s declaration All chapters of this thesis were written by Robert J. Ward. Comments and editorial input were provided by the supervisors Richard A. Griffiths, John W. Wilkinson, Nina Cornish and Jim J. Groombridge as listed below. Chapter 5 also received comments and editorial input from additional researchers within the University of Kent and from external institutions. All research within this thesis was approved by the University of Kent, School of Anthropology and Conservation Research Ethics Committee. Chapter 1. The chapter was written by R.J. Ward and received editorial suggestions from R.A. Griffiths and J.J. Groombridge. Chapter 2. R.J. Ward, R.A. Griffiths, J.W. Wilkinson and N. Cornish conceived the idea. R.J. Ward designed the study, conducted all data collection and analyses, and wrote the manuscript with editorial input from the other co-authors. It has been submitted to Scientific Reports with permission of all co-authors and accepted for publication with some modifications. Chapter 3. R.J. Ward, R.A. Griffiths, J.W. Wilkinson and N. Cornish conceived the idea. R.J. Ward designed the study, conducted all data collection and analyses, and wrote the manuscript with editorial input from the other co-authors. Chapter 4. R.J. Ward, R.A. Griffiths, J.W. Wilkinson and N. Cornish conceived the idea. R.J. Ward conducted all data collection and wrote the manuscript with input from the other co-authors. Chapter 5. R.J. Ward, R.A. Griffiths, J.J. Groombridge, J.W. Wilkinson and N. Cornish conceived the idea. R.J. Ward conducted data collection in Jersey, conducted all analyses and wrote the manuscript with input from the other co- V authors. Samples from France were provided by Mickaël Barrioz and Franck Paysant from the Société Herpétologique de France. Comments and editorial input were received from all supervisors plus H. Jackson, C. Durrant and C. Kindler. Chapter 6. The chapter was written by R.J. Ward and received proofreading suggestions from R.A. Griffiths and J.J. Groombridge. VI Abstract Global biodiversity losses are being driven by anthropogenic pressures; the most pervasive of which is habitat loss resulting in fragmentation and population isolation. These issues are prevalent throughout Europe due to high intensity agriculture and increasing human population densities. Limitations imposed by resources and the secretive lifestyles of many species hinder the ability of conservationists to undertake status assessments and identify conservation actions. This thesis investigates the threats to an isolated population of grass snakes Natrix helvetica on the island of Jersey, providing recommendations for conservation management and recovery, whilst testing the suitability of tools for monitoring cryptic species. Grass snakes were historically widespread throughout Jersey; however, anthropogenic influences have restricted their distribution to the west and southwest. Furthermore, recent monitoring efforts have detected few individuals and their status is unknown. Intensive surveys to locate individuals combined with occupancy and N- mixture (abundance) models identified continued occupancy of semi-natural sites in the island’s west and southwest, but also highlighted poor detectability of the species unless utilising a large survey effort. Therefore, a large amount of effort is required to determine absence of snakes, and declines in the population cannot be detected with reasonable power. Occupancy models were more reliable than N- mixture models, particularly due to the risks of closure violation when estimating abundance. Nonetheless, N-mixture models estimated an abundance of 48 snakes (95% CI: 231279) across the study sites. Radio-tracking also provided evidence for low detection rates. Additionally snakes demonstrated small ranges (mean: 2.48 ha ± 3.54 SD), site fidelity, preferences for ranges close to paths and VII compost heaps, but avoided crossing roads. Snakes were positively associated with structurally complex habitats including rough grassland, dense scrub and gorse at multiple spatial scales, but negatively with open and wooded habitats. Species distribution modelling indicated similar habitat