The value of weeds for wildlife and implications for management by Emma H. Carlos, B. Env. Sc. (Hons) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Deakin University December, 2012 Preface All research for this thesis had relevant ethics approval and government permits. Research in Chapter 2 was approved by the Deakin University Human Research Ethics Committee (STEC-16-2008-CARLOS). Research for Chapters 3 – 5 was conducted under permit from the Department of Sustainability and Environment (10004671) and procedures were approved by the Deakin University Animal Welfare Committee (A49- 2008). This thesis is presented as a series of stand-alone research papers. Each data chapter (Chapters 2 – 5) has either been submitted for publication or has been written with the intention for submission to a specific journal. As required by each journal, data chapters are set out with their own Abstract, Introduction, Methods, Results and Discussion section. An effort has been made to make the style and format of the thesis sections consistent; however, some journal specific requirements have been retained. To minimise undue repetition all references have been consolidated at the end of the thesis. I am the primary investigator and contributor to all aspects of this research but, as some data chapters are written with the intention for submission to a specific journal, the contribution of co-authors, Maria Gibson (Principle Supervisor) and Michael Weston (Associate Supervisor) is recognised. Both provided significant guidance on each data chapter and commented on drafts of each chapter. Thus, data chapters occasionally refer to ‘we’ in recognition of co-author contributions. i Acknowledgements I am grateful to the many people who have provided support, encouragement, assistance and advice to me throughout my PhD journey. Firstly, thank you to my supervisors, Maria (Mary) Gibson and Mike Weston. Your knowledge, wisdom and unwavering support have been invaluable throughout my research process. Mary, your trust and belief in me has been endless and has encouraged me to challenge myself in ways I never anticipated. I have grown in confidence and ability because of your support and I sincerely thank you for this. Mike, I thank you for wholeheartedly going out of your way to help me in every aspect of this research. The passion and enthusiasm you communicate for research has been infectious and your humour has lightened many a dull day. Together, you both have made one amazing team and there is nothing more I could have hoped for. My research would not have been possible without the support from the brilliant Parks Victoria staff at the You Yangs Regional Park and Point Cook Coastal Park. In particular: Lauren Kelly, for so cheerfully welcoming me to the You Yangs and for her friendly and approachable nature that put me at ease right from the word go; Bernie McCarrick at the Point Cook office for being an enthusiastic supporter of my research and making so much possible, and; David Flagg for being so accommodating, easy- going and for making such a significant contribution towards the spraying of ‘my’ boneseed at the You Yangs. Thank you also to David Roberts, John Argote, Mark Cullen, Russell Brooks and Alex Tomsic, and to Mike Helmen, Mick Smith and the rest of the team at Serendip Sanctuary. I am privileged to have had the opportunity to work and stay in these very special parks and it means a great deal to me that you were all so supportive. ii Financial support was provided through the ANZ Holsworth Wildlife Research Endowment, Birds Australia (Victoria) and Deakin University Postgraduate Scholarship. There are so many people within Deakin University that have helped me and I sincerely thank you all. In particular, I have always been provided with amazing technical support from Clorinda Schofield. We would all be lost without you Clorinda, thank you so much. I am also grateful to James Hill and Jess Bywater, for the technical support you provided; Robyn Cook, Clare Hake and more recently, Heather Andrews, thank you for your assistance with the endless paper chase; thanks are due to Kelly Miller, for her advice in the initial stages of my social research component, and to Desley Whisson, for her animal handling expertise and patience during the training process. The enthusiastic people who volunteered for me during various stages of my project were amazing. I am so thankful to you all. A special thanks to Fanny Chevrier, Anthony Rendall, Erin Lennox, Sarah Ludlow, Kristin Scherlies, Debby Carlos and Jackson Carlos, who joined me on multiple trips for extended periods; your commitment and patience, particularly in the face of endless vegetation surveys, was admirable. I wouldn’t have managed the field work component without the help so willingly provided by so many; I am forever grateful. During the analysis phase I was fortunate to have been provided with statistical advice from Gerry Quinn and Dale Nimmo. I especially thank you, Dale, for still having the courage to ask me how the stats were going, even when the answer was likely to result in a considerable loss of your valuable time. Thank you to those who have waded through drafts and provided constructive comments and editing throughout the writing process, with a special mention to Kristin Scherlies and Emmi Scherlies during the final write-up. My thanks also go to my colleagues and fellow PhD journeyers, past and present, for the brainstorming, encouragement, advice, laughter and tears that have been shared. In particular: Nicole Schumann, I feel fortunate to have travelled through the PhD journey iii with you from start to finish, and the brainstorming sessions we had helped not only my PhD, but many aspects of life; Evelyn Chia, your friendship means a lot to me, I’m glad you went against my advice and chose the desk next to the window; Christine Connelly and Tanya Pyk, your company and encouragement has always been well-timed and very much appreciated. Finally, I thank my friends and family – Mum, Dad, Marlene, Jackson, Krissy, Heidi, Armstrong, Emmi and Riki. You not only provided support, encouragement and love, but were also some of my most reliable volunteers. I will always be grateful for your faith in me, and I love you all dearly. iv Table of contents Preface ............................................................................................................................... i Acknowledgements.......................................................................................................... ii Table of contents.............................................................................................................. v List of figures .................................................................................................................ix List of tables.................................................................................................................... xi Definitions and abbreviations...................................................................................... xiv Abstract .......................................................................................................................... xv Chapter 1 General Introduction ...................................................................................................... 1 1.1 Invasive species and conservation: A global issue............................................. 2 1.2 The impacts of weeds on wildlife....................................................................... 2 1.2.1 The values of weeds for wildlife ................................................................. 3 1.3 Impacts of weed management on wildlife.......................................................... 6 1.4 Thesis overview................................................................................................ 10 1.4.1 Thesis objectives and structure.................................................................. 10 1.4.2 Study areas ................................................................................................ 13 Chapter 2 Weeds and wildlife: Perceptions and practices of weed managers........................... 18 2.1 Abstract............................................................................................................. 19 2.2 Introduction....................................................................................................... 20 2.3 Methods ............................................................................................................ 22 2.3.1 Statistical analysis ..................................................................................... 24 2.4 Results............................................................................................................... 24 2.4.1 Observations of wildlife during weed management.................................. 25 2.4.2 Attitudes towards wildlife during weed management............................... 25 2.4.3 Adaptive management for wildlife............................................................ 26 v 2.4.4 The objectives and success of weed management..................................... 30 2.5 Discussion......................................................................................................... 31 2.5.1 Weed management projects: purpose, perceptions and practice............... 31 2.5.2 Weeding for wildlife ................................................................................. 33 2.6 Appendix A......................................................................................................