Invasive non-native plants retain native mammal communities in novel ecosystems Jasmin G. Packer Invasive non-native plants retain native mammal communities in novel ecosystems Jasmin G. Packer Submitted for the degree of Doctor of Philosophy October 2013 Declaration I certify that this work contains no material which has been accepted for the award of any other degree or diploma in any university or other tertiary institution in my name and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text. In addition, I certify that no part of this work will, in the future, be used in a submission in my name, for any other degree or diploma in any university or other tertiary institution without the prior approval of the University of Adelaide and where applicable, any partner institution responsible for the joint-award of this degree. I give consent to this copy of my thesis, when deposited in the University Library, being made available for loan and photocopying, subject to the provisions of the Copyright Act 1968. I also give permission for the digital version of my thesis to be made available on the web, via the University’s digital research repository, the Library catalogue and also through web search engines, unless permission has been granted by the University to restrict access for a period of time. Signature Date Table of Contents Declaration ……………… ...................................................................................................................iv Table of Contents.............................................................................................................................v Abstract……………………....................................................................................................................ix Acknowledgements ........................................................................................................................xi Chapter 1 Introduction.............................................................................................................. 1 1.1 Biodiversity conservation in human-altered ecosystems ...............................................2 1.1.1 Novel ecosystems: non-native plants as threats and facilitators of biodiversity....................3 1.1.2 Fauna responses to the landscape matrix............................................................................4 1.1.3 Fauna responses to habitat thresholds................................................................................6 1.2 Blackberry and small mammal communities..................................................................7 1.2.1 The Mount Lofty Ranges .....................................................................................................8 1.2.2 Study species: blackberry (Rubus anglocandicans)............................................................. 10 1.2.3 Study species: small native mammal communities ............................................................ 11 1.3 Research aims ..............................................................................................................16 Chapter 2 Ecosystem engineering by non-native blackberry (Rubus anglocandicans) retains small mammal communities in novel ecosystems.......................................................... 19 2.1 Introduction .................................................................................................................20 2.2 Methods.......................................................................................................................23 2.2.1 Study area ........................................................................................................................ 23 2.2.2 Small mammal surveys...................................................................................................... 26 2.2.3 Environmental surveys...................................................................................................... 28 2.2.4 Statistical analyses............................................................................................................ 30 2.3 Results..........................................................................................................................34 2.3.1 Differences between environmental characteristics .......................................................... 34 2.3.2 Small mammal differences and drivers at site scale........................................................... 36 2.3.3 Small mammal differences and drivers at the microhabitat scale....................................... 41 2.3.4 Fauna responses and competition across landscape scales................................................ 44 2.4 Discussion ....................................................................................................................47 2.4.1 Effect on environmental characteristics ............................................................................ 47 2.4.2 Drivers of small mammal responses.................................................................................. 48 2.4.3 Implications for conservation and restoration ................................................................... 50 Chapter 3 Predation risk and competition increases chronic stress in novel ecosystems.... 53 3.1 Introduction .................................................................................................................54 3.2 Methods.......................................................................................................................58 3.2.1 Study area and sites.......................................................................................................... 58 3.2.2 Animal trapping................................................................................................................ 58 3.2.3 Blood sampling and measurements................................................................................... 58 3.2.4 Habitat assessment........................................................................................................... 60 3.2.5 Statistical analysis............................................................................................................. 62 3.3 Results..........................................................................................................................63 3.3.1 Neutrophil / lymphocyte ratio........................................................................................... 64 3.3.2 Comparison with reference ranges.................................................................................... 64 3.3.3 Effect of habitat on health condition................................................................................. 67 3.3.4 Effect of season on health condition ................................................................................. 67 3.4 Discussion ....................................................................................................................72 3.4.1 Site scale: territorial stress in human-altered habitat......................................................... 72 3.4.2 Landscape scale: reduced health condition in a fragmented system .................................. 74 3.4.3 Conservation physiology as an early warning signal........................................................... 75 Chapter 4 Non-native blackberry (Rubus anglocandicans) increases habitat quality and recruitment for native mammals................................................................................................. 77 4.1 Introduction .................................................................................................................78 4.2 Methods.......................................................................................................................82 4.2.1 Study area ........................................................................................................................ 82 4.2.2 Study population .............................................................................................................. 84 4.2.3 Habitat characteristics ...................................................................................................... 85 4.2.4 Statistical analyses............................................................................................................ 89 4.3 Results..........................................................................................................................91 4.3.1 Habitat differences ........................................................................................................... 91 4.3.2 Population fitness and productivity................................................................................... 96 4.4 Discussion ..................................................................................................................101 4.4.1 Facilitator of habitat quality............................................................................................ 101 4.4.2 Ranking the influence of habitat thresholds on population persistence ........................... 102 4.4.3 Future research directions .............................................................................................. 103 Chapter 5 Framework for quantifying the response of native fauna to non-native plants105 5.1 Overview....................................................................................................................106