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Sources of carbon isotope variation in kangaroo bone collagen and tooth enamel

Murphy, Brett P., Bowman, David and Gagan, Michael K. (2007). Sources of carbon isotope variation in kangaroo bone collagen and tooth enamel. Geochimica et Cosmochimica Acta,71(15):3847-3858.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 13 times in Scopus Article | Citations

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IRMA ID A00004xPUB69
Title Sources of carbon isotope variation in kangaroo bone collagen and tooth enamel
Author Murphy, Brett P.
Bowman, David
Gagan, Michael K.
Journal Name Geochimica et Cosmochimica Acta
Publication Date 2007
Volume Number 71
Issue Number 15
ISSN 0016-7037   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-34447501998
Start Page 3847
End Page 3858
Total Pages 12
Place of Publication Oxford, UK
Publisher Elsevier
Field of Research 0402 - Geochemistry
HERDC Category C1 - Journal Article (DEST)
Abstract The stable carbon isotopic composition (expressed as delta C-13) of herbivore remains is commonly used to reconstruct past changes in the relative abundance Of C-4 versus C-3 grass biomass (C-4 relative abundance). However, the strength of the relationship between herbivore delta C-13 and C-4 relative abundance in extant ecosystems has not been thoroughly examined. We determined sources of variation in delta C-13 of bone collagen and tooth enamel of kangaroos (Macropus spp.) collected throughout Australia by measuring delta C-13 of bone collagen (779 individuals) and tooth enamel (694 individuals). An index of seasonal water availability, i.e. the distribution of rainfall in the C-4 versus C-3 growing seasons, was used as a proxy for C-4 relative abundance, and this variable explained a large proportion of the variation in both collagen delta C-13 (68%) and enamel delta C-13 (68%). These figures increased to 78% and 77%, respectively, when differences between kangaroo species were accounted for. Vegetation characteristics, such as woodiness and the presence of an open forest canopy, had no effect on collagen or enamel delta C-13. While there was no relationship between collagen delta C-13 and kangaroo age at death, tooth enamel produced later in life, following weaning, was enriched in C-13 by 3.5& relative to enamel produced prior to weaning. From the observed relationships between seasonal water availability and collagen and enamel delta C-13, enrichment factors (epsilon*) for collagen-diet and enamel-diet (post-weaning) were estimated to be 5.2 parts per thousand +/- 0.5 (95% CI) and 11.7 parts per thousand +/- 0.6 (95% CI), respectively. The findings of this study confirm that at a continental scale, collagen and enamel delta C-13 of a group of large herbivores closely reflect C-4 relative abundance. This validates a fundamental assumption underpinning the use of isotopic analysis of herbivore remains to reconstruct changes in C-4 relative abundance.
Keywords amazonian rain forests
c-4 grasses
dietary niche breadths
eastern grey-kangaroo
late pleistocene
mammalian herbivores
red kangaroos
seasonal water availability
southwestern united-states
stable-isotope
DOI http://dx.doi.org/10.1016/j.gca.2007.05.012   (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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