Reintroduction ecology of the Eurasian crane Grus grus Submitted by Andrea Soriano Redondo to the University of Exeter as a thesis for the degree of Doctor of Philosophy in Biological Sciences In March 2017 This thesis is available for Library use on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. I certify that all material in this thesis which is not my own work has been identified and that no material has previously been submitted and approved for the award of a degree by this or any other University. Signature:…………………………………………………………… 1 To my parents 2 Abstract Successful conservation strategies to increase the survival prospects of a population must be accompanied by an accurate knowledge of the population dynamics. In this thesis, I examine the population dynamics of Eurasian cranes (Grus grus) in the UK and assess the impact of a reintroduction on the future population size and distribution. Additionally, I cover other aspects of crane conservation, such as public engagement in crane conservation and crane resilience to extreme weather events. To do so, I use a wide range of tools: Internet-based monitoring methods, stochastic matrix population models, point process models and GPS-accelerometer tracking devices. I show that there is a geographic gradient in interest in reintroduction projects; people living near the project area have a greater interest than people from areas further away. I also show that the UK crane population is acting as a pseudo-sink; current levels of survival and productivity allow the population’s persistence but immigration is driving population recovery. Nevertheless, the productivity of the UK population is low and measures to improve it should be implemented. The reintroduction of 90 birds in the Somerset Levels has decreased the relative importance of immigration and is likely to increase the projected population size by 50% over the next 50 years. However, the increase in population numbers will not be accompanied by a large expansion in the population range. Cranes will likely colonize large wetlands with low perimeter-to-area ratios near already occupied areas, but the reintroduction will increase the dispersal potential of the species. Finally, I find that during an extreme flooding event, crane foraging areas became limited to a small unflooded patch, but cranes coped with this event through behavioural flexibility, by increasing their foraging time. Together, these results highlight the importance of reaching a broad understanding of population dynamics in order to implement effective conservation strategies. 3 Acknowledgements Firstly, I am really thankful to Stuart Bearhop for encouraging me to apply for this PhD, for his support and expertise during these three years and for the great deal of freedom I have had to work from several places at different stages of the thesis. Geoff Hilton (Wildfowl & Wetlands Trust, WWT) has been extremely supportive and essential for the progress of this thesis; he has constantly guided me throughout all the issues that have arisen. Steve Votier has been willing to discuss any idea and help in any step of the way. Leigh Lock (The Royal Society for the Protection of Birds, RSPB) provided advice and support, especially in the early stages of the PhD. Big thanks to The Great Crane Project team and its volunteers without whom any of this would have been possible. Particularly, Damon Bridge did an exceptional job at keeping track of cranes and was always willing to help. The team from the RSPB West Sedgemoor reserve was extremely welcoming and their office door was always open for me to shelter on rainy days. Somerset landowners and farmers could not have been more accommodating, letting me access their fields to sample invertebrates and crane faeces. During the long and usually lonely fieldwork season Julie Merrett and her children were a surrogate family to me and I really want to thank her for that. And a very special thank you to Jenny Peason, the best masters student I could have asked for, she was absolutely brilliant during the fieldwork and a great friend. Stuart and Steve group meetings have been a great opportunity to discuss research ideas and have helped me to progress with the thesis, so thanks to Ian, Tom, Freydis, Mitch, Matt, George, Nicole, Cat, Beth, Dimas, Rich and all the undergraduate and masters students that attended through the years. I 4 would like to thank as well, Janine Illian and Charlotte Jones-Todd for her help and assistance during my research stay at the University of St. Andrews. These three years wouldn’t have been the same without all the people I got to meet in Penryn, so a massive thanks to my officemates: Phil, Dom, Aisha, Ed, Miranda, Lili, Rita, Ana, Sarah, Emily, Lucy, Miguel and all the people that at some point were based in the Farmhouse. I also want to say a massive thank to Jesica, Giovanni, Elvire, Elisa, Paqui, Gloria, Lauri, Itxaso, JP, Tomasa, Atta, Pablo and to everyone else who have been awesome friends for the last few years. It has been so much fun, I really cherish the moments spent together, the walks along the coastal paths, the beach days, the BBQs, the parties, the pub nights and so on. My most special thanks go to my friends and family in Barcelona. They always understood and supported my decision to move to Cornwall and pursue my career. I’m particularly thankful to my parents and sister for being so loving and supportive during these years I have been abroad, you have been amazing! Lastly, thank you to Jorge, these three years would have been very different without him. He has been a source of inspiration and a constant support, both emotionally and academically, and I am deeply thankful for that. 5 Contents Abstract ....................................................................................................................... 3 Acknowledgements .................................................................................................... 4 Contents ...................................................................................................................... 6 List of Tables and Figures ........................................................................................ 10 Author’s Declaration ................................................................................................. 18 Chapter 1: General introduction .............................................................................. 20 1.1 General framework ............................................................................................ 21 1.2 Study species .................................................................................................... 26 1.3 Study site .......................................................................................................... 29 1.4 Reintroduction ................................................................................................... 32 1.4 Thesis outline .................................................................................................... 34 Chapter 2: Internet-based monitoring of public perception of conservation ....... 36 2.1 Abstract ............................................................................................................. 37 2.2 Introduction ....................................................................................................... 37 2.3 Offsite metrics ................................................................................................... 42 2.3.1 Assessing patterns of public interest in a species: the red kite .................... 43 2.3.2 Assessing patterns of interest in conservation awareness projects: RSPB . 47 2.4 Onsite metrics ................................................................................................... 48 2.4.1 Assessing the success in communicating conservation outcomes: the Eurasian crane .................................................................................................... 49 2.4.2 Assessing the success in online public engagement: WWT ........................ 52 2.5 Conclusions ....................................................................................................... 54 6 Chapter 3: Immigration and reinforcement drive population dynamics in a long- lived bird: Implications for Eurasian crane conservation ...................................... 56 3.1 Abstract ............................................................................................................. 57 3.2 Introduction ....................................................................................................... 58 3.3 Methods ............................................................................................................ 61 3.3.1 Data collection ............................................................................................ 61 2.3.2 Model parameters and stochastic matrix population models implementation ............................................................................................................................ 62 2.3.3 Population viability analysis under different immigration and reintroduction scenarios ............................................................................................................. 64 3.4 Results .............................................................................................................. 65 2.4.1 Model parameters and stochastic matrix population