1. Fenner School of Environment and Society; The Australian National University; Canberra ACT 0200 Australia
2. ARC Centre of Excellence for Environmental Decisions; National Environmental Research Program; The Australian National University; Canberra ACT 0200 Australia
3. CSIRO Ecosystem Sciences; Canberra ACT 2601 Australia
4. Department of Zoology; La Trobe University; Bundoora Vic. 3086 Australia
5. CSIRO Ecosystem Sciences; Floreat WA 6014 Australia
6. School of Animal Biology; The University of Western Australia; Perth WA 6009 Australia