Top predators can induce ecological state-shifts over large spatio-temporal scales in Australian forest ecosystems Daniel Oscar Hunter A thesis in fulfilment of the requirement for the degree of Doctor of Philosophy School of Biological, Earth and Environmental Sciences University of New South Wales, Australia November 2018 1 2 3 4 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 student contributed greater than 50% of the content in the publication and is the “primary author”, ie. the student was responsible primarily for the planning, execution and preparation of the work for publication • The student 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 (if this box is checked, you may delete all the material on page 2) Some of the work described in this thesis has been published and it has ☐ been documented in the relevant Chapters with acknowledgement (if this box is checked, you may delete all the material on page 2) 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 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. Name Daniel Hunter Signature Date 28/07/18 5 Postgraduate Coordinator’s Declaration (to be filled in where publications are used in lieu of Chapters) I declare that: • the information below is accurate • where listed publication(s) have been used in lieu of Chapter(s), their use complies with the Thesis Examination Procedure • the minimum requirements for the format of the thesis have been met. PGC’s Name PGC’s Signature Date (dd/mm/yy) 6 For each publication incorporated into the thesis in lieu of a Chapter, provide all of the requested details and signatures required Details of publication #1: Full title: Not all predators are equal: a continent-scale analysis of the effects of predator control on Australian mammals Authors: Daniel Hunter, Malgorzata Lagisz, Viyanna Leo, Shinichi Nakagawa, Mike Letnic Journal or book name: Mammal Review Volume/page numbers: 48: 108-122 Date accepted/ published: 28 November 2017 Status Published x Accepted and In In progress press (submitted) The Candidate’s Contribution to the Work Study was conceptualised by Daniel Hunter and Mike Letnic. Data collection was performed by Daniel Hunter and Viyanna Leo. Data analysis were performed by Daniel Hunter, Malgorzata Lagisz, Shinichi Nakagawa and Mike Letnic. Daniel Hunter and Mike Letnic wrote the manuscript. Malgorzata Lagisz contributed to writing the results section. Location of the work in the thesis and/or how the work is incorporated in the thesis: This publication forms all of chapter 2 in my thesis. The publication forms the foundation for the rest of my thesis. Primary Supervisor’s Declaration I declare that: • the information above is accurate • this has been discussed with the PGC and it is agreed that this publication can be included in this thesis in lieu of a Chapter • All of the co-authors of the publication have reviewed the above information and have agreed to its veracity by signing a ‘Co-Author Authorisation’ form. Supervisor’s name Supervisor’s signature Date 31/07/2018 Mike Letnic Details of publication #2: Full title: Reintroducing Tasmanian devils to mainland Australia can restore top-down control in ecosystems where dingoes have been extirpated. Authors: Daniel Hunter, Thomas Britz, Menna Jones, Mike Letnic 7 Journal or book name: Biological Conservation Volume/page numbers: 191: 428-435 Date accepted/ published: 24 July 2015 Status Published x Accepted and In In progress press (submitted) The Candidate’s Contribution to the Work Study was conceptualised by Daniel Hunter and Mike Letnic. Data collection was performed by Daniel Hunter. Data analysis were performed by Daniel Hunter, Thomas Britz and Mike Letnic. Daniel Hunter and Mike Letnic wrote the manuscript. Menna Jones and Mike Letnic provided guidance on manuscript structure as co-author and supervisor respectively. Location of the work in the thesis and/or how the work is incorporated in the thesis: This publication forms all of chapter 5. This work is pitched as a hypothetical solution to restoring top predator ecological function in areas where dingoes remain persecuted and/or functionally extinct. Primary Supervisor’s Declaration I declare that: • the information above is accurate • this has been discussed with the PGC and it is agreed that this publication can be included in this thesis in lieu of a Chapter • All of the co-authors of the publication have reviewed the above information and have agreed to its veracity by signing a ‘Co-Author Authorisation’ form. Supervisor’s name Supervisor’s signature Date 31/07/2018 Mike Letnic Add further boxes if required. You may delete any boxes not used 8 Abstract Top predators are recognised as important ecological constituents because empirical studies demonstrate that they can supress populations of herbivores and smaller predators. Despite their important roles, top predators are subject to human-induced population declines globally. The main drivers of decline include habitat loss, habitat modification and human persecution resulting from conflict for resources such as livestock. One outcome of their declines has been a widespread interest in documenting the ensuing ecological effects owing to the fact that top predators are recognised as keystone species. In terrestrial ecosystems, research has shown that top predators can influence ecosystems and their species composition owing to direct effects on smaller predators and their prey species. These direct effects have been linked to far-reaching indirect effects at multiple trophic levels, that extend to vegetation and even the physical attributes of the landscape. The role of top predators is increasingly being viewed as an important component of healthy and functional ecosystems around the world. This thesis explores the hypothesis that Australia’s top terrestrial predator, the dingo (Canis dingo), induces shifts in mammal populations and vegetation in Australian forest ecosystems. The novelty of this thesis is that I test this hypothesis using longitudinal methodologies through time as opposed to snap-shot surveys. In my first chapter, I provide a detailed overview of the current state of knowledge regarding the role of top predators around the world. Specifically, I detail how top predators drive trophic cascades via direct and indirect effect pathways. My second chapter contains comprehensive meta-analyses which investigate the effects of dingo and fox control on mammal species. This provides a robust foundation for identifying knowledge 9 gaps. My third chapter builds on the meta-analysis by conducting a multi-year occupancy analysis in forest ecosystems to determine how dingo control affects the occupancy of invasive mesopredators and native mammals. In chapter 4, I perform generalised linear modelling and quantile regression to improve our understanding of how dingoes supress foxes and to determine if environmental predictors have any bearing on this interaction. Finally, I test if reintroducing a marsupial predator back to mainland Australia can act as a surrogate for the dingo in some parts by restoring some lost ecological interactions to areas where dingoes have been extirpated. 10 Acknowledgements I acknowledge the Traditional Owners of the land on which I conducted all of my field work and I pay my respects to their Elders, past and present and future, and any Elders from any community who may read this thesis. I would like to sincerely thank my primary supervisor Associate Professor Mike Letnic. Your patience and lateral thinking has made me a better scientist. I have learned so much from you and I honestly couldn’t have asked for a more brilliant and creative mind to help guide my learning. Thanks Mike, I hope I have provided a decent return on investment! I’m very grateful to Dr. Rosalie Chapple and the Blue Mountains World Heritage Institute. Rosalie helped me find this PhD and the BMWHI provided me with a top-up scholarship which greatly helped me to focus on my research. Thank you very much Rosalie and I hope the research in this thesis helps realise some of your organisation’s goals. Thanks to the UNSW, the School of Biological, Earth and Environmental Sciences and the Centre for Ecosystem Science for their support during my candidature. The UNSW is a world-class research institution and I feel privileged to have undertaken my PhD here. I would especially like to thank Professor Richard Kingsford, Sharon Ryall and Jono Russell – all of you have helped me along my extended PhD journey in many ways. I’d especially like to thank you for your patience and support as I juggled my PhD and my professional work as a filmmaker – permitting me space and time has helped me realise my ultimate goal of making wildlife and conservation films for the BBC, National Geographic, Plimsoll and the ABC – so thank you very 11 much. A huge thanks to all my lab mates who helped make my transition to Sydney from Jan Juc a smooth one. Thanks also to all of the volunteers that helped me during the fieldwork phase of my PhD. My friends and family are the most important part of my life.