For Tony Harman, my dear friend and passionate entomologist, who nurtured in me a love of all things creepy crawly Acknowledgements I am grateful to many different people for their part in the completion of this work. Firstly, I owe a debt of gratitude to my principal supervisor Scott Johnson for his guidance throughout my time here. In particular, I am thankful for Scott’s unrivalled speed in turning around drafts, his writing acumen and the obvious investment he places in the interests of his students. I am grateful too for the support and encouragement provided by my supervisory panel – both near and far – by David Ellsworth and Jo Staley. I am thankful for the work of Sabine Nooten; her infectious passion for ants, her valuable experience of community ecology studies and our impromptu cups of tea. I am grateful to Philip Smith for his meticulous proof-reading skills. Throughout my time here, I have had the honour of working with several enthusiastic volunteers and undergraduate students – including David Fidler, Marcel Torode, Jenni Kremer, Rhiannon Rowe and Aqeel Abbas – whose tireless, exemplary efforts in the field and lab made this work a possibility. I have had the pleasure of working alongside some wonderful students and post-docs, many of whom I will maintain life-long connections with. I am particularly thankful to my office-mate Jessica Rigg for her humour and friendship, as well as our (probably medically inadvisably-frequent) motivational cups of tea with Kylie Brice and Caroline Fromont. I am grateful that I got to share this PhD experience with my good friend and PhD-counterpart Kirk Barnett – his scientific rigour, statistical genius and philosophical discussions have been invaluable and helped to form the basis of a deep friendship. Words cannot express the gratitude I have for the unwavering support of my partner William Balmont – for taking a risk with me and uprooting to the other side of the world; for listening to me talk about insects for years with sustained, sincere interest; for his tireless work in the field and laboratory in his free time; and for his unquestionable love and support throughout the emotional rollercoaster that completing a PhD entails. I am thankful too for the love and support of our dear friends Lanilà and Ivan Hiltpold, without whom life both in and out of work would have been a whole lot less spirited and fulfilling. My thanks go to the Yoga Shed Richmond – especially Catherine Sherlock and our inspiring teacher and friend Anneriek Favelle. It has been a privilege to be a part of such a welcoming and enriching community, at a time when we needed it most. I am thankful for the long-range, Skype enabled support provided by family and friends back in the UK, particularly my mother and nan who have a seemingly never-ending supply of encouragement and love. I am especially grateful for the advice and infectious excitement of my inspiring friend, the late Tony Harman – to whom this work is dedicated – who encouraged me to take a chance, move to his beloved Australia and study the bugs he cherished so much. Last, but by no means least, I am grateful to the staff and students at the Institute for having me these past years. I have very much enjoyed being an active part of such a vibrant, international research community. In particular, I am thankful for the tireless, often silent work of the administrative, laboratory and site staff who were always there to advise and help when I needed it – especially David Harland, Patricia Hellier, Jenny Harvey, Gavin McKenzie and Vinod Kumar. This work was supported by a Higher Degree Research Scholarship from the Hawkesbury Institute for the Environment, Western Sydney University. Declaration of Authenticity The work presented in this thesis is, to the best of my knowledge and belief, original except as acknowledged in the text. I hereby declare that I have not submitted this material, either in full or in part, for a degree at this or any other institution. Contents List of Tables ................................................................................................................................. i List of Figures .............................................................................................................................. iii Abstract .......................................................................................................................................... v Preface......................................................................................................................................... viii Chapter One: General Introduction .......................................................................................... 1 1.1 The importance of invertebrates in terrestrial ecosystems .................................... 1 1.2 Climatic and atmospheric change.............................................................................. 1 1.3 Invertebrates and environmental change ................................................................. 2 1.4 Altered precipitation impacts on invertebrate communities ................................. 2 1.5 Elevated CO2 impacts on invertebrate communities ............................................. 6 1.6 Rationale ....................................................................................................................... 8 1.7 Thesis overview ........................................................................................................... 9 1.8 Thesis outline ............................................................................................................. 10 Chapter Two: Grasslands, invertebrates and precipitation: a review of the effects of climate change ............................................................................................................................. 13 2.1 Summary ..................................................................................................................... 13 2.2 Introduction ............................................................................................................... 14 2.3 Invertebrate responses to precipitation change .................................................... 15 2.4 Invertebrate-mediated feedbacks on plant communities ..................................... 21 2.5 Conclusions and future directions .......................................................................... 22 Chapter Three: Predicted changes in rainfall patterns cause temporary perturbations in a grassland invertebrate assemblage which quickly recover .................................................... 25 3.1 Summary ..................................................................................................................... 25 3.2 Introduction ............................................................................................................... 26 3.3 Materials and Methods .............................................................................................. 29 3.4 Results ......................................................................................................................... 32 3.5 Discussion ................................................................................................................... 54 Chapter Four: The effects of atmospheric change on forest invertebrates ....................... 59 4.1 Summary ..................................................................................................................... 59 4.2 Why are forest invertebrate communities important? .......................................... 60 4.3 Atmospheric change and invertebrates .................................................................. 61 4.4 Responses of forest invertebrates to elevated CO2 concentrations ................... 62 4.5 Responses of forest invertebrates to elevated ozone concentrations ................ 75 4.6 Interactions between carbon dioxide and ozone .................................................. 78 4.7 Conclusions and future directions .......................................................................... 80 Chapter Five: Atmospheric change causes declines in woodland arthropods and impacts specific trophic groups .............................................................................................................. 82 5.1 Summary ..................................................................................................................... 82 5.2 Introduction ............................................................................................................... 83 5.3 Materials and methods .............................................................................................. 85 5.4 Results ......................................................................................................................... 89 5.5 Discussion ................................................................................................................... 98 Chapter Six: Atmospheric change causes declines and compositional changes in populations of ants in Eucalypt woodland ........................................................................... 104 6.1 Summary ................................................................................................................... 104 6.2 Introduction ............................................................................................................. 105 6.3 Materials and Methods ...........................................................................................