Understanding the characteristics and role of refuges in the persistence of the plains mouse (Pseudomys australis) in arid landscapes Lauren Ivy Young A thesis submitted to fulfil requirements for the degree of Doctor of Philosophy Faculty of Science The University of Sydney 2018 Photograph on title page: Pseudomys australis in the cracking clay by Alistair Stewart. Declaration of originality This is to certify that to the best of my knowledge, the content of this thesis is my own work. This thesis has not been submitted for any degree or other purposes. I certify that the intellectual content of this thesis is the product of my own work and that all the assistance received in preparing this thesis and sources have been acknowledged. Signature Lauren Ivy Young Date: 25 May 2018 i Contents Table of Figures .............................................................................................................................. v List of Tables ............................................................................................................................... viii Candidate contribution to manuscripts ........................................................................................... x Acknowledgements ........................................................................................................................ xi Thesis Abstract............................................................................................................................. xiii Chapter 1. General Introduction ................................................................................................. 1 The effects of rainfall on desert ecosystems ............................................................................... 2 Small mammal resource use in desert landscapes ...................................................................... 5 Drought refuges .......................................................................................................................... 7 Pseudomys australis .................................................................................................................... 9 Aims of the research ................................................................................................................. 13 Layout of the thesis ................................................................................................................... 13 References ................................................................................................................................. 14 Chapter 2. Spatial and temporal dynamics of Pseudomys australis during a dry period ......... 26 Abstract ..................................................................................................................................... 26 Introduction ............................................................................................................................... 27 Materials and Methods .............................................................................................................. 31 Study location ....................................................................................................................... 31 Live-trapping ........................................................................................................................ 33 Rainfall data .......................................................................................................................... 35 Presence of predators ............................................................................................................ 37 Statistical analyses ................................................................................................................ 39 Results ....................................................................................................................................... 41 Pseudomys australis population dynamics ........................................................................... 41 Reproduction ......................................................................................................................... 46 Presence of predators ............................................................................................................ 47 Discussion ................................................................................................................................. 50 Conclusions ........................................................................................................................... 54 Acknowledgments ..................................................................................................................... 54 References ................................................................................................................................. 55 Chapter 3. Spatial ecology and shelter resources of a threatened desert rodent (Pseudomys australis) in refuge habitat ............................................................................................................ 62 ii Abstract ..................................................................................................................................... 62 Introduction ............................................................................................................................... 63 Materials and Methods .............................................................................................................. 66 Study sites ............................................................................................................................. 66 Live-trapping ........................................................................................................................ 67 Radio-tracking ...................................................................................................................... 68 Statistical analyses ................................................................................................................ 71 Results ....................................................................................................................................... 73 Movement and home range size ........................................................................................... 73 Home range overlap .............................................................................................................. 76 Shelter use ............................................................................................................................. 78 Discussion ................................................................................................................................. 80 Home range size and habitat preference ............................................................................... 81 Home range overlap .............................................................................................................. 83 Shelter use ............................................................................................................................. 84 Conclusions ........................................................................................................................... 85 Acknowledgments ..................................................................................................................... 86 References ................................................................................................................................. 86 Chapter 4. The influence of food and shelter resources on the occurrence of Pseudomys australis during a dry period ......................................................................................................... 92 Abstract ..................................................................................................................................... 92 Introduction ............................................................................................................................... 92 Materials and Methods .............................................................................................................. 97 Study location ....................................................................................................................... 97 Live-trapping ........................................................................................................................ 98 Resource data collection ....................................................................................................... 99 Statistical analyses .............................................................................................................. 102 Results ..................................................................................................................................... 107 Pseudomys australis occurrence and resource availability ................................................. 107 Spatial and temporal influences on resource availability ................................................... 113 Discussion ............................................................................................................................... 115 Shelter resources ................................................................................................................. 116 Food resources ...................................................................................................................