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Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions

Bowman, David, Murphy, Brett and McMahon, Clive (2010). Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions. Journal of Biogeography,37(3):499-505.

Document type: Journal Article
Citation counts: Altmetric Score Altmetric Score is 7
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IRMA ID A00004xPUB53
Title Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions
Author Bowman, David
Murphy, Brett
McMahon, Clive
Journal Name Journal of Biogeography
Publication Date 2010
Volume Number 37
Issue Number 3
ISSN 0305-0270   (check CDU catalogue open catalogue search in new window)
Start Page 499
End Page 505
Total Pages 7
Place of Publication UK
Publisher Wiley-Blackwell Publishing Ltd.
HERDC Category C1 - Journal Article (DEST)
Abstract Aim: Australia lost a diverse assemblage of large marsupial herbivores in the late Pleistocene, with suggestions that the extinctions were biased towards browsers. In modern times two bovines, the Asian water buffalo (Bubalus bubalis) and banteng (Bos javanicus), have established feral populations in the Northern Territory, Australia. Buffalo have aggressively expanded throughout the savanna landscape, yet banteng remain near their point of introduction on the Cobourg Peninsula. We hypothesized that this difference is related to feeding ecology, possibly reflecting a legacy of the Pleistocene extinctions. Location: Western Arnhem Land, Northern Territory, Australia. Methods: Analysing a previously published dataset of body mass and feeding ecology of extinct and extant marsupial herbivores, we evaluated whether browsers were at greater risk of extinction than grazers. We compared the carbon isotope composition and nitrogen content of banteng and buffalo dung in order to evaluate the hypotheses that the differences in invasion success are related to feeding ecology, and that seasonal variation in browse consumption is linked to changing nutritional quality of grass. Results: Controlling for body mass, the Pleistocene extinctions were clearly biased towards browsers. Introduced banteng appear to be primarily browsers, with their diets comprising 40% grass in the wet season and 15% in the late dry season. Buffalo have a more variable diet, with an increasing proportion of browse from the wet (30%) to the late dry season (75%), and can therefore be described as switching from grazer to browser. The decline of grass in the diet of both species appears to reflect the decline in the nutritional value of grass through the dry season, an inference supported by the negative relationship between δ13C values and the nitrogen content of dung. Main conclusions: Banteng and buffalo are much larger than extant native herbivores, of which browsers are restricted to isolated rocky habitats. This suggests that banteng and buffalo have filled niches made vacant following the Pleistocene extinctions. The success of buffalo appears to be related to their greater dietary breadth, which enables them to graze and browse in eucalypt savannas, whilst the browsing banteng remain tethered to a mosaic of rain forest patches. The restriction of browsers may be a long-range consequence of habitat transformations associated with Aboriginal landscape burning.
DOI http://dx.doi.org/10.1111/j.1365-2699.2009.02206.x   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
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Created: Sun, 21 Mar 2010, 17:33:23 CST by Sarena Wegener