Identifying key threats and conservation requirements for the Critically Endangered Yangtze finless porpoise Lisa Mogensen A thesis submitted for the degree of Doctor of Philosophy University College London (UCL) Originally submitted September 2018 Supervisors: Dr. Samuel Turvey, Institute of Zoology (IOZ), Regent’s Park, London Prof. Helen Chatterjee, University College London (UCL), Gower Street, London Declaration I, Lisa Mogensen, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Signed: i ii Abstract Evidence-based conservation is the most effective way to preserve biodiversity. However, for many species robust long-term data sets are not available and so the process of selecting effective interventions is poorly-informed and at risk of being ineffective. The Critically Endangered Yangtze finless porpoise (Neophocaena asiaeorientalis), a unique freshwater cetacean endemic to the Yangtze River, China, is subject to numerous anthropogenic threats that have led to significant population decline in recent decades. Conservation of this species has been severely limited by a poor understanding of the causes of population decline. By using four novel lines of analysis on already existing data sets, this study firstly assessed whether there is currently a sufficient evidence base to inform conservation of this species. This process established conservation-relevant conclusions and identified key remaining knowledge gaps without having to use valuable resources and time to gather further data. Subsequently, boat-based mapping studies have revealed conservation-relevant spatial and temporal patterns relating to potential threat presence and YFP habitat use on multiple spatial scales, whilst extensive interview-based surveys with fishers have been used to gather detailed information on patterns in illegal fishing gear use and YFP bycatch, as well as conservation-relevant socio-economic data. In addition, longitudinal interview data has provided an invaluable insight into changes in human-wildlife interactions and high-risk human behaviours over time. Lastly, an interview survey with key stakeholders involved in Yangtze finless porpoise conservation has demonstrated that evidence-based conservation is not being applied to this species, meaning that interventions are not targeted to key causes of decline and there is a risk of conservation complacency and extinction of a second Yangtze River cetacean. The multi-disciplinary research presented here has demonstrated how the conservation process for data-poor endangered species can be improved by increasing the knowledge base surrounding potential threats and causes of direct and indirect mortality, which has wider application for other at-risk species. iii Impact Statement › This research has generated £15,000 funding for vital research into a Critically Endangered species. › The methods used here have potential for wider applications to other species requiring conservation attention. › The research presented here has both academic implications and wider impacts outside of academia for direct conservation of the studies target species. › This research has been presented at the 2018 European Conference on Conservation Biology (ECCB) in Jyvaskyla, Finland. › The conclusions of this study will be presented at a workshop with local managers and stakeholders involved in conservation of the study species in China. Evidence-based conservation is the most effective way to improve the application of interventions aimed at preserving biodiversity. By using the Critically Endangered Yangtze finless porpoise, a unique freshwater cetacean, as a prominent case study, the research presented here has demonstrated how the conservation of data-poor endangered species around the world can be improved by increasing the knowledge base surrounding potential threats and causes of major mortality. The impacts of this study are both global (research methods applicable to conservation of other endangered species) and more localised and specific (conservation of this specific species within China). Firstly, the understanding of some key threats to this species is improved using four lines of analysis on already existing data sets that have been combined and used in novel ways to extract conservation-relevant information. This has demonstrated that in cases where a data deficiency is preventing evidence-based conservation, it is vital to critically evaluate the information content of available data sets, even if they were not originally collected for conservation purposes. This approach could be useful to improve conservation-relevant knowledge of many other data-poor species and can be applied to other conservation-based academic research. Following on, this study then demonstrates the interaction of a Critically Endangered unique cetacean with potential threats on multiple spatial scales and establishes the seasonal changes in species distribution and interaction with threats using a rapid simultaneous threat- species boat-based survey technique. This technique could be applied to research on other cetacean species. Further to this, the use of local ecological knowledge as a technique to gather conservation-relevant data is applied to improve the knowledge of the interaction of this species with one of the known causes of mortality: fishing bycatch. This method also has potential for wider application to other species and systems. This study has additionally assessed the current reserve network for the Yangtze finless porpoise for the first time, both through boat-based surveys but also through an appraisal of the management and design of the reserves themselves. The results demonstrated here can iv directly be applied to improve the allocation and management of protected areas aimed at conserving the Yangtze finless porpoise in China and hopefully improve prospects for this species. In addition, all the results presented in this study are relevant to in-country conservation efforts for this species. The main results of this study have been presented at the 2018 ECCB conference. In addition, all the information from this study will be disseminated within a workshop attended by prominent Yangtze finless porpoise stakeholders, policy makers, and managers in October 2018 in China, with the hope that key gaps and areas for improvement of in-situ Yangtze finless porpoise conservation can be addressed and a second Yangtze River cetacean extinction can be avoided. Further to this, most of the results presented here will be published in peer-reviewed academic publications for dissemination to interested academic parties. v Acknowledgements Firstly, and mostly, thank you to Prof. Samuel Turvey for his enduring passion for wildlife conservation despite the challenges involved. The species you research are lucky to have you on their side, and I also feel very lucky to have worked with you on this project. Thank you for your sustained and seemingly endless patience with this research and with me at the more challenging points during this project. I have appreciated your guidance and feedback at every stage and learned an incredible amount from you in the last 4 years. I’ll never forget the adventures in China - 干杯! Thank you to Prof. Helen Chatterjee for continued guidance and assistance throughout the PhD process and for very useful assistance with the interview survey structure. This study was made possible because of ongoing support from the IHB in Wuhan, China. Special thank you to Dr. Yujiang Hao and Dr. Zhigang Mei for assistance with in-country logistics, for establishing lines of contact with local representatives and boat captains, and for finding fantastic field assistants. A big thank you to Dr. Xavier Harrison for vital support and advice with the statistics and modelling required for this research. I’ve learnt an incredible amount from you in a very short period, and your patience and coffee have contributed significantly to the output of this project. Thank you to Dr. Ben Collen for much-needed support and advice during the early stages of this project. You offered sympathetic guidance and support even though it was not your responsibility. The conservation community has lost a fantastic conservationist, but more importantly, a kind-hearted friend. You will forever be missed. A special thanks to the impressive efforts of my in-country volunteers Michael Hui, Candice Low, Lesley, Iris, and Xianyuan Zeng. Thank you for your dedication, hard work and continued patience whilst forever getting lost finding elusive fishing villages! One of my oldest friends, Rory Hodgson, for pursuing with the complex python code required for some of the GIS challenges of this project. Dr Richard Pearson for a necessary reality check and vital guidance on dealing with spatial data. I am very grateful to all the organisations that have funded this project, namely the Mohammed Bin Zayed Species Conservation Fund, Synchronicity Earth, and the New England Aquarium Marine Conservation Action Fund. Field work has been a crucial component of this work, without which I could not have gathered the essential data that has allowed us to further our understanding of this unique and wonderful species. vi Contents 1 Chapter 1: Introduction 1 1.1 Conservation of threatened species – evidence-based vs. precautionary approaches 2 1.2 What data are needed to conserve threatened taxa? 3 Understanding and quantifying decline in