The Platypus: Historical, Ecological, and Behavioural Advances to Improve the Conservation of an Elusive Species
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The platypus: historical, ecological, and behavioural advances to improve the conservation of an elusive species Tahneal Hawke Supervisors: Richard Kingsford and Gilad Bino A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Biological, Earth and Environmental Sciences, Faculty of Science March 2020 Thesis/dissertation sheet Surname/Family Name : Hawke Given Name/s : Tahneal Kathleen Abbreviation for degree as give in the University : PhD calendar Faculty : Science School : Biological, Earth and Environmental Sciences The platypus: historical, ecological, and behavioural advances to Thesis Title : improve the conservation of an elusive species Abstract 350 words maximum: (PLEASE TYPE) Platypuses are evolutionarily and morphologically unique, making them one of the world’s most iconic animals. Due to their cryptic, nocturnal nature, they are notoriously difficult to study in the wild, limiting knowledge of their distribution, ecology, and behaviour, hindering effective assessments of decline and status. Recently, studies have suggested declines resulting from a range of threats, but despite their distribution overlapping Australia’s most regulated rivers, the impacts of dams remains relatively unstudied. In my thesis, I aimed to address specific knowledge gaps for platypuses, assessing potential past and present distribution, the impact of dams, and their movement behaviours. Chapter 1 highlights ongoing species declines and provides insight into the life history of the platypus. In my second chapter, I compiled the most comprehensive database on the distribution and abundance of platypus, which allowed me to identify potential declines in range and number. The inclusion of historical data highlighted how shifting baselines have changed perspectives on platypus abundance, impacting perceptions on the magnitude of decline. For Chapters 3 – 5, I examined impacts of large dams and river regulation by surveying upstream and downstream of dams, and on adjacent unregulated rivers, and tracked movement of platypuses downstream of dams. In Chapter 3 I examined population dynamics, finding populations downstream of dams with significantly altered flow regimes had lower abundances and densities of platypuses than above dams, while the opposite was true for rivers where flow regimes had been improved. In Chapter 4, movement tracking highlighted interactions among individuals in a localised pool and revealed no detrimental impacts of an environmental flow on the Snowy River. Long-term movement analysis on regulated rivers in Chapter 5 suggested platypus have restricted movements, with implications for declining populations, given areas of decline are unlikely to be supplemented by migrating platypuses. My thesis provides critical insight on platypus declines using historical baselines and identifies how dams can be major drivers of declines, while also highlighting the benefits of their improved management. These conclusions, combined with insights into movement behaviour, offer valuable information to guide conservation management of threats for the long-term viability of this iconic species. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents a non-exclusive licence to archive and to make available (including to members of the public) my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known. I acknowledge that I retain all intellectual property rights which subsist in my thesis or dissertation, such as copyright and patent rights, subject to applicable law. I also retain the right to use all or part of my thesis or dissertation in future works (such as articles or books). …………………………………………………………… ……….……………………...…….… Signature Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. Requests for restriction for a period of up to 2 years can be made when submitting the final copies of your thesis to the UNSW Library. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. i Originality statement ‘I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project's design and conception or in style, presentation and linguistic expression is acknowledged.’ Signed …………………………………………….............. Date …………………………………………….................. ii Copyright statement ‘I hereby grant the University of New South Wales or its agents a non-exclusive licence to archive and to make available (including to members of the public) my thesis or dissertation in whole or part in the University libraries in all forms of media, now or here after known. I acknowledge that I retain all intellectual property rights which subsist in my thesis or dissertation, such as copyright and patent rights, subject to applicable law. I also retain the right to use all or part of my thesis or dissertation in future works (such as articles or books).’ ‘For any substantial portions of copyright material used in this thesis, written permission for use has been obtained, or the copyright material is removed from the final public version of the thesis.’ Signed ……………………………………………........................... Date …………………………………………….............................. Authenticity statement ‘I certify that the Library deposit digital copy is a direct equivalent of the final officially approved version of my thesis.’ Signed ……………………………………………........................... Date …………………………………………….............................. iii Inclusion of Publications Statement UNSW is supportive of candidates publishing their research results during their candidature as detailed in the UNSW Thesis Examination Procedure. Publications can be used in their thesis in lieu of a Chapter if: • The candidate contributed greater than 50% of the content in the publication and is the “primary author”, ie. the candidate was responsible primarily for the planning, execution and preparation of the work for publication • The candidate has approval to include the publication in their thesis in lieu of a Chapter from their supervisor and Postgraduate Coordinator. • The publication is not subject to any obligations or contractual agreements with a third party that would constrain its inclusion in the thesis Please indicate whether this thesis contains published material or not: This thesis contains no publications, either published or submitted for ☐ publication Some of the work described in this thesis has been published and it has ☒ been documented in the relevant Chapters with acknowledgement This thesis has publications (either published or submitted for ☐ publication) incorporated into it in lieu of a chapter and the details are presented below CANDIDATE’S DECLARATION I declare that: • I have complied with the UNSW Thesis Examination Procedure • where I have used a publication in lieu of a Chapter, the listed publication(s) below meet(s) the requirements to be included in the thesis. Candidate’s Name Signature Date (dd/mm/yy) iv Preface This thesis is a compilation of my own work with guidance and contribution from my supervisors Richard Kingsford and Gilad Bino. This thesis consists of six chapters, including an overall introductory chapter for background context, four data chapters of original research completed as part of this doctorate, and a concluding discussion chapter which summarises the implications of this research. Data chapters are either published, submitted for publication, or intend to be published. This has resulted in slight formatting differences and the repetition of some sections, particularly in the introductions when describing the biology and ecology of platypuses, and in the methodology when describing trapping procedures. Each chapter is self-contained, but references have been consolidated into a single bibliography at the end of the thesis. Collective terms acknowledge co- authors on paper. Specific contributions of co-authors are listed at the beginning of each chapter. Platypuses were trapped and handled in accordance with guidelines approved by the NSW Department of Planning, Industry and Environment (SL101655), (P15/0096-1031.0 & OUT15/26392), and UNSW’s Animal Care and Ethics Committee (16/14A). This research was made possible through an RTP scholarship. Funding for this research was provided by the Australian Research Council (Linkage LP150100093) and supported by Taronga Conservation Society. In-kind support was provided from the Centre of Ecosystem Science UNSW, National Parks and Wildlife Service, and Austral Ecology. v Acknowledgements Firstly, a huge thank you to my supervisors, Richard and Gilad, without whom this thesis would not have been possible. To Richard, your tenacious yet light-hearted manner of dealing with every situation, combined