Body mass and extinction risk in Australian marsupials: The ‘Critical Weight Range’ revisited
Version of Record online: 12 JAN 2009
© 2009 The Authors. Journal compilation © 2009 Ecological Society of Australia
Volume 34, Issue 1, pages 35–40, February 2009
How to Cite
JOHNSON, C. N. and ISAAC, J. L. (2009), Body mass and extinction risk in Australian marsupials: The ‘Critical Weight Range’ revisited. Austral Ecology, 34: 35–40. doi: 10.1111/j.1442-9993.2008.01878.x
- Issue online: 12 JAN 2009
- Version of Record online: 12 JAN 2009
- Accepted for publication February 2008.
- exotic predator;
- extinction selectivity;
- feral cat;
- population decline;
- red fox
Australian mammals have suffered an exceptionally high rate of decline and extinction over the last two hundred years. Body mass is linked to extinction risk in Australian mammals, but the nature of this association is controversial. A widely held view is that species of intermediate body mass (between 35 and 5500 g, the ‘critical weight range’, CWR) have declined most severely. However, the existence of the CWR has been disputed. In this paper we clarify the relationship of decline status and body mass in Australian marsupials. We show that the form of this relationship differs for ground-living versus arboreal species, and for species from low versus high rainfall areas. Among ground-living species and those from low-rainfall areas, declines were strongly size-selective and concentrated on species within the CWR. For the remaining species, decline was only weakly related to body mass with no evidence of heightened risk for species of intermediate size. We conclude that for terrestrial species in low rainfall areas, species within the CWR are most at risk of decline and extinction.