The current decline of tropical marsupials in Australia: Is history repeating?

Fisher, Diana O., Johnson, Chris N., Lawes, Michael J., Fritz, Susanne A., Mccallum, Hamish, Blomberg, Simon P., Vanderwal, Jeremy, Abbott, Brett, Frank, Anke, Legge, Sarah, Letnic, Mike, Thomas, Colette R., Fisher, Alaric, Gordon, Iain J. and Kutt, Alex (2014) The current decline of tropical marsupials in Australia: Is history repeating?. Global Ecology and Biogeography, 23 2: 181-190. doi:10.1111/geb.12088


Author Fisher, Diana O.
Johnson, Chris N.
Lawes, Michael J.
Fritz, Susanne A.
Mccallum, Hamish
Blomberg, Simon P.
Vanderwal, Jeremy
Abbott, Brett
Frank, Anke
Legge, Sarah
Letnic, Mike
Thomas, Colette R.
Fisher, Alaric
Gordon, Iain J.
Kutt, Alex
Title The current decline of tropical marsupials in Australia: Is history repeating?
Journal name Global Ecology and Biogeography   Check publisher's open access policy
ISSN 1466-822X
1466-8238
Publication date 2014-01-01
Year available 2013
Sub-type Article (original research)
DOI 10.1111/geb.12088
Volume 23
Issue 2
Start page 181
End page 190
Total pages 10
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell
Collection year 2014
Language eng
Formatted abstract
Aim: A third of all modern (after 1500) mammal extinctions (24/77) are Australian species. These extinctions have been restricted to southern Australia, predominantly in species of 'critical weight range' (35-5500g) in drier climate zones. Introduced red foxes (Vulpes vulpes) that prey on species in this range are often blamed. A new wave of declines is now affecting a globally significant proportion of marsupial species (19 species) in the fox-free northern tropics. We aim to test plausible causes of recent declines in range and determine if mechanisms differ between current tropical declines and past declines, which were in southern (non-tropical) regions.

Location: Australian continent

Methods: We used multiple regression and random forest models to analyse traits that were associated with declines in species range, and compare variables associated with past extinctions in the southern zones with current tropical (northern) declines.

Results: The same two key variables, body mass and habitat structure, were associated with proportion-of-decline in range throughout the continent, but the form of relationships differs with latitude. In the south, medium-sized species in open habitats of lower rainfall were most likely to decline. In the tropics, small species that occupy open vegetation with moderate rainfall (savanna) are now experiencing the most severe declines. Throughout the continent, large-bodied species and those in structurally complex habitats (rainforest) are secure.

Main conclusions: Our results indicate that there is no mid-sized 'critical weight range' in the north. Because foxes are absent from the tropics, we suggest that northern Australian marsupial declines are associated with predation by feral cats (Felis catus) exacerbated by reduced ground level vegetation in non-rainforest habitats. To test this, we recommend experiments to remove cats from some locations where tropical mammals are threatened. Our results show that comparative analysis can help to diagnose potential causes of multi-species decline. 
Keyword Comparative methods
Critical weight range
Introduced predators
Mammal extinction
Marsupials
Random forest models
Tropical conservation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Biological Sciences Publications
 
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