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The persistence of common wombats in road impacted environments Erin Roger PhD thesis School of Biological, Earth and Environmental Sciences University of New South Wales August 2009 “We treat the attrition of [wildlife] lives on the road like the attrition of lives in war: horrifying, unavoidable, justified.” Barry Lopez, Apologia PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: Roger First name: Erin Other name/s: Katherine Abbreviation for degree as given in the University calendar: PhD School: School of Biological Earth & Environmental Faculty: Science Sciences Title: The persistence of common wombats in road impacted environments Abstract 350 words maximum: (PLEASE TYPE) There is growing global concern over the influence of road development on the conservation of biodiversity and on the functioning of ecosystems. Published reviews in the field of road ecology have identified that most research has examined the effects of roads linearly and have advocated for research at landscape scales. Among the many effects roads have, one of the most significant is the loss of animal life resulting from collisions with vehicles. Despite this, little is known of what toll this has on animal populations and how these impacts vary with scale. This stems from the perception that impacts are localised and that animals killed are typically considered common, and therefore not of great conservation concern. This thesis challenges this notion by showing that the impacts of fatalities can affect populations at landscape extents and that commonness is not a barrier to localised extinction risk. To achieve this I focus on the common wombat; an example of a common species for which road impacts have never been previously examined. Chapter 1 provides an overview of the importance of scale in quantifying road impacts and the debate surrounding common species persistence in road environments. Chapter 2 assesses habitat use of wombats in a road environment at a local scale. Results suggest that wombats select for roadside habitat and as a result populations could be under threat. Chapter 3 is a predictive model of wombat road fatalities which demonstrates the importance of incorporating habitat use in predictive fatality modelling. Through use of a spatially explicit population viability analysis, Chapter 4 demonstrates that roads, in conjunction with other threats can affect the persistence of a common species at a local scale. Chapter 5 is a landscape extent assessment of wombat habitat use, finding that increased effort should be employed in evaluating how reserves confer resilience to species from the impacts of roads and that habitat quality can dictate road-based fatality rates. Chapter 6 summarises the research presented in the thesis and suggests direction for future work, particularly the importance of evaluating the interplay between susceptibility and abundance on species vulnerability in road environments. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all property rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstracts International (this is applicable to doctoral theses only). …………………………………………………………… ……………………………………..……………… ……….……………………...…….… Signature Witness 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 must be made in writing. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. FOR OFFICE USE ONLY Date of completion of requirements for Award: THIS SHEET IS TO BE GLUED TO THE INSIDE FRONT COVER OF THE THESIS 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 …………January 12, 2010........................................ COPYRIGHT STATEMENT ‘I hereby grant the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstract International (this is applicable to doctoral theses only). I have either used no substantial portions of copyright material in my thesis or I have obtained permission to use copyright material; where permission has not been granted I have applied/will apply for a partial restriction of the digital copy of my thesis or dissertation.' Signed …………………………………………….............. Date …………January 12, 2010........................................ AUTHENTICITY STATEMENT ‘I certify that the Library deposit digital copy is a direct equivalent of the final officially approved version of my thesis. No emendation of content has occurred and if there are any minor variations in formatting, they are the result of the conversion to digital format.’ Signed …………………………………………….............. Date …………January 12, 2010........................................ Preface These theses consists of four stand-alone papers (chapters two to five) that have either been published, accepted, or are currently in review. Therefore each chapter is self contained and some repetition occurs. Because each chapter is a stand-alone journal article, the tables and figures are not sequentially numbered throughout the thesis, rather each chapter is presented as it would appear as a published journal article. I have also kept journal specific formatting for each chapter. The chapters that have been published are identical to the published version with the exception of some of the figures which I have changed from their printed black and white version to colour. To prevent unnecessary duplication a single reference list is provided at the end of the thesis formatted in the style for Biodiversity and Conservation. This thesis is a compilation of my own work, with guidance from my supervisors Daniel Ramp and Shawn Laffan. Apart from the contributions of my co- authors outlined below I conceptualised my research, conducted all data analysis and wrote and illustrated the manuscripts. I also generated all maps and photographs included in this thesis. My co-authors proof-read and edited the final manuscript versions as is required for publications. The contributions of my co-authors are detailed below. Chapter 2: Roger, E., S. W. Laffan, and D. Ramp. 2007. Habitat selection by the common wombat (Vombatus ursinus) in disturbed environments: Implications for the conservation of a ‘common’ species. Biological Conservation 137, 437-449. S.W. Laffan assisted with GIS analysis and GIS layer generation. He also gave conceptual advice and guidance in his function as my supervisor. D. Ramp wrote the GAM script and provided advice and assistance with modelling within the program R. He also contributed significant intellectual input and general guidance in his function as my supervisor. Chapter 3: Roger, E., and D. Ramp. 2009. Incorporating habitat use in models of fauna fatalities on roads. Diversity and Distributions 15, 222-231. D. Ramp wrote the GAM script and provided advice and assistance with modelling within the program R. He also contributed significant intellectual input and general guidance in his function as my supervisor. Chapter 4: Roger, E., Laffan, S.W., and Ramp, D. (accepted 05/01/2010) Road impacts a tipping point for wildlife populations in threatened landscapes. Population Ecology. S.W. Laffan assisted with GIS analysis and spatial analysis results. He also gave conceptual advice and guidance in his function as my supervisor. D. Ramp wrote the GAM script and provided advice and assistance with modelling within the program R. He also contributed significant intellectual input and general guidance in his function has my supervisor. Chapter 5: Roger, E., Ramp, D., Bino, G., Laffan, S.W. (in review) Rethinking the impact of roads on common species persistence. Landscape Ecology (submitted 10/08/09). D. Ramp wrote the GAM script and provided valuable advice with modelling within the program R. He also contributed significant intellectual input and general guidance in his function as my supervisor. G. Bino developed the predictive and dependent layers for the GIS analysis and refined the modelling process. He also gave conceptual advice and guidance. S.W. Laffan gave conceptual advice and guidance in his function as my supervisor. Acknowledgements My gratitude goes, as ever, to a great many people for their peerless support and patience. I am greatly indebted to Daniel Ramp for introducing me to the field of road ecology. His support, vision and mentorship meant a great deal to me throughout my PhD (even if it did involve extensive modelling).

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