THE FEASIBILITY OF REINTRODUCING THE EURASIAN LYNX Lynx lynx TO SCOTLAND David Andrew Hetherington M.A. (Hons) Environmental Geography, University of Aberdeen, UK A thesis presented for the degree of Doctor of Philosophy at the University of Aberdeen 2005 DECLARATION I declare that I composed this thesis and that the work presented herein is my own, with any contribution to data collection by others having been specifically acknowledged in the text. This work has not been submitted in any previous application for a degree. All quotations have been distinguished by quotation marks and the sources of information have been acknowledged. David A. Hetherington March 2005 i ABSTRACT Reintroductions have become an important wildlife management tool in many parts of the world in recent decades. However, the UK has not yet reintroduced any nationally extinct mammal species. One of these missing species, the Eurasian lynx, has recently been reintroduced to several European countries. This study investigates the feasibility of reintroducing the Eurasian lynx to Scotland by examining the history of the species in Britain, and by determining if there is sufficient habitat and prey for a viable population. Skeletal remains of lynx have been recovered from cave sites across Scotland, England and Wales. Recently acquired radiocarbon dates, as well as etymological, linguistic and cultural evidence, show that lynx continued to inhabit areas of northern Britain until at least the early mediaeval period. This contradicts theories that lynx died out in Britain because of climatic processes. Anthropogenic factors, such as severe deforestation, declining populations of deer, and persecution driven by protection of livestock, are instead likely to have brought about the species’ extirpation in Britain. As lynx did not become extinct in Britain due to natural processes, they qualify ethically as a candidate for reintroduction. Modern Scotland witnessed large-scale reafforestation during the 20th century, and many regions are now relatively well wooded. Deer populations have also grown considerably and deer now inhabit all parts of the Scottish mainland. Most sheep are no longer grazed in woodland, thus considerably reducing scope for lynx depredation on livestock. Furthermore, human attitudes towards the environment, wildlife and predators, are generally much more positive now than in previous centuries. The reversal of extinction processes suggests that conditions for lynx in Scotland could be suitable once more. A rule-based GIS analysis identified two large networks of habitat patches: one in the Highlands, and one in the Southern Uplands. Currently, the level of connectivity between the two networks is weak. By examining the relationship between lynx and wild ungulate densities in parts of Europe, it was predicted from the average deer biomass in the two networks, that the Highlands habitat network could support around 400 lynx, and the Southern Uplands, around 50 lynx. A Population Viability Analysis using the Leslie matrix-based software package RAMAS/age suggested that a lynx population living at a carrying capacity of 400 would be viable in the long term. However, a lynx population at a carrying capacity of 50 would be too small to be viable in isolation. Movement corridors between the Highlands and the Southern Uplands, which run through benign habitats and avoid significant barriers, are therefore essential for the long-term viability of a Southern Uplands lynx population. In order to have a high probability of surviving for 10 years after release, the minimum size of a founder population composed of 1 to 3-year old lynx should be 12 to 32 individuals, with an equal sex ratio. The most suitable lynx for a Scottish reintroduction would come from the wild of Latvia, Estonia and SW Finland. Despite their long absence, the reintroduction of lynx to Scotland is biologically feasible. ii ACKNOWLEDGEMENTS Many people from a range of disciplines and countries have helped me in different ways during my research. Firstly, however, I must thank the following organisations and individuals without whose generous financial assistance, the research would not have been possible: The Highland Foundation for Wildlife, The Robert Nicol Trust, Lynx Information Systems Ltd, Wildshots, The Cross Trust, Nick Blake, Audrey Hughes and Angus Pelham Burn. I am very grateful for the academic supervision of Dr Martyn Gorman of the University of Aberdeen, and the invaluable advice of both Roy Dennis of the Highland Foundation for Wildlife, and Professor David Miller of the Macaulay Land Use Research Institute. The constructive comments and suggestions of Drs Urs & Christine Breitenmoser, and Dr Fridolin Zimmermann of KORA, made researching lynx in a lynx-less country that little less bewildering. Many PhD students and staff at the Zoology Department of the University of Aberdeen have provided me with much-valued support and advice during my years in the Department. I would like to acknowledge the assistance of Steve Adams, Chantelle Anandan, Steve Bird, Gill Campbell, Yolanda Corripio, Marie Fish, Richard Genna, Jen Gow, Kevin Mackenzie, Ian Mackie, Colin MacLeod, Barry Nicholls, Matt Oliver, Nia Phillips, Juliette Pont, Eduardo Tedesco, Mandy Tulloch, and Ellie Watts. Whether it was to answer my incessant questions, dig out some information, show me around their country, or put me in touch with the right people, the efforts of the following people are greatly appreciated: Ole Anders, Zanete Andersone-Lilley, Christof Angst, Helen Armstrong, Jonathan Ball, Niall Benvie, John Blore, Pete Cairns, Douglas Campbell, Paul Cavill, Connie Christie, Janez Čop, Ian Fergusson, Iain Fraser, Duncan Halley, Ray Hetherington, Roger Jacobi, Saskia Jancke, Andrew Kitchener, Friedhart Knolle, Tatjana Kontio, Tor Kvam, Jens Laass, Xavier Lambin, Colin Lavin, Tom Lord, Alastair MacGugan, Alan Mackintosh, Keith Marshall, Sandy Mather, Fiona McPhie, Kellie Meyer, Iain Morrison, Colm O’Boyle, Terry O’Connor, Aivars Ornicans, Klara Petrzelkova, Kirstie Philpot, Stuart Piertney, Adrian Price, Stephanie Prior, Ewan Purser, Andreas Ryser, Sabin Schlatter, Krzysztof Schmidt, Colin Shedden, Jim Smart, Christina Smith, Philippe Stahl, Brian Staines, Geir Steinheim, Peter Sunde, Manuela von Arx, Kuno von Wattenwyl, Alastair Ward, Charles Warren, Tony Waterhouse, Jonathan Watt, Lars Werdelin, Emily Wilson, Mark Woess, and Derek Yalden. Lastly, I owe a great deal to my family. My parents have given me so much during the years of my research (much of it edible). My Mum, May Hetherington, has been inspirational as she fought her own battle against the odds and won. My Dad, Andy Hetherington, provided me with a roof over my head, and washed more than his fair share of the dishes. My grandmother, May Mann, whose unwavering support both for me, and for lynx, has been a great source of reassurance. My grandfather, Andrew Hetherington, has always been interested to learn more about lynx. iii DEDICATION This thesis is dedicated to my grandfather Noel Mann, a clever man who contributed so much to my education. iv CONTENTS Author’s Declaration xxXxi Abstract xxxxii Acknowledgements xxXiii Dedication Xxxiv CHAPTER 1: An Introduction to Eurasian lynx and their reintroduction xX 1 in Europe CHAPTER 2: Are Eurasian lynx native to Britain and if so, how did they xX22 become extinct? CHAPTER 3: Do the processes that led to lynx extinction still operate in xX40 modern Scotland? CHAPTER 4: How much potential habitat is there for Eurasian lynx in xX57 Scotland? CHAPTER 5: How many lynx could Scotland’s deer populations support? X101 CHAPTER 6: Population viability analysis: how many lynx are enough? X121 CHAPTER 7: A perspective on results and future directions X155 References X173 Appendix X207 v CHAPTER 1 AN INTRODUCTION TO EURASIAN LYNX AND THEIR REINTRODUCTION IN EUROPE 1 1.1 Species restoration in the UK In the UK, several species, which were regionally or nationally extirpated, are now recovering their former range as a result of reintroductions and natural recolonisation. A few successful reintroductions of birds and mammals have so far been carried out in Scotland. The capercaillie Tetrao urogallus was reintroduced in the 1830s and 40s by private landowners after it had become extinct during the eighteenth century (Ritchie, 1920). Goshawks Accipiter gentilis were unofficially reintroduced to Scotland from the 1960s, while white-tailed eagles Haliaeetus albicilla were reintroduced through a project begun by the Nature Conservancy in 1975 (R. Dennis, pers. comm.). A joint project begun by the Royal Society for the Protection of Birds and the Nature Conservancy Council in 1989, saw a series of releases return the red kite Milvus milvus to Scotland (R. Dennis, pers. comm.). In the past few centuries, several mammal species have been reintroduced in Scotland, although most of these were unofficial releases. Red deer Cervus elaphus and roe deer Capreolus capreolus were translocated from the Highlands to several parts of southern Scotland during the 18th and 19th centuries, mainly for hunting (Ritchie, 1920). Red squirrels Sciurius vulgaris almost became extinct in Scotland but were reintroduced from England and Scandinavia during the late 18th and 19th centuries (Ritchie, 1920). In recent years, an official reintroduction of pine martens Martes martes to the Southern Uplands was carried out by the Forestry Commission, while clandestine releases of polecats Mustela putorius are thought to have occurred in Argyll