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A study of stable carbon, nitrogen and oxygen isotopes in modern Australian marsupial herbivores, and their relationships with environmental conditions

Fraser, Rebecca A.

Description

This research has examined the stable isotope ecology of three species of Australian marsupial herbivores; koalas, kangaroos and wombats, from a range of different geographic and climatic regions. The broad objective of this thesis research was to examine stable isotopes in modem marsupial species to provide baseline data that can be used to inform palaeoecological studies. In the European, African and north American continents stable isotope analyses of terrestrial mammal remains are...[Show more]

dc.contributor.authorFraser, Rebecca A.
dc.date.accessioned2013-11-22T04:43:02Z
dc.identifier.otherb22783647
dc.identifier.urihttp://hdl.handle.net/1885/10818
dc.description.abstractThis research has examined the stable isotope ecology of three species of Australian marsupial herbivores; koalas, kangaroos and wombats, from a range of different geographic and climatic regions. The broad objective of this thesis research was to examine stable isotopes in modem marsupial species to provide baseline data that can be used to inform palaeoecological studies. In the European, African and north American continents stable isotope analyses of terrestrial mammal remains are widely used to investigate the diet and ecology of modern and fossil species. By comparison, similar investigations using Australian native mammals are not as prevalent. Australian landscapes and the physiologies of some native marsupials are in many respects almost unique; therefore, an isotopic study of this continent is warranted. The investigation of modern specimens provided the experimental conditions to observe some of the baseline systematics of stable isotopes in marsupial tissues. Firstly, the study explored the relationships between stable isotopes in the animals' diet, bone collagen and dental enamel, and the isotopic differences between these two tissues. Secondly, it examined isotopic variability on different levels: intra-population variability in o13C and o15N values in bone collagen and both inter and intra-tooth variability in o13C and o180 values in enamel. Thirdly, it examined the relationships between marsupial stable isotope ratios and environmental signals such as moisture availability, rainfall and habitat. The koalas provided an opportunity to examine an obligate C3 browser with an extremely consistent diet and conservative lifestyle. The constant nature of their diet enabled the effects of climate on stable isotope ratios to be examined with the knowledge that there is no C4 dietary input. The stable isotopes in the kangaroos and the wombats were examined from a broader environmental perspective than the koalas because their geographic coverage is far more extensive- from the arid to the alpine. Because the kangaroos and wombats are both grazers, their o13C values reflected the availability of the C3 and the C4 plants in their respective habitats. Most significantly, microsampling of the continuously growing incisors of wombats revealed that variation in 813C and 8180 values along the tooth can be used as a proxy for seasonality. The results from this research provide empirical data for future research in isotopic biochemistry and significant baseline data for use in palaeodietary modelling and palaeoenvironmental interpretation of fossil marsupials. These findings are specific to the Australian palaeoecological context.
dc.language.isoen_AU
dc.titleA study of stable carbon, nitrogen and oxygen isotopes in modern Australian marsupial herbivores, and their relationships with environmental conditions
dc.typeThesis (PhD)
dcterms.valid2006
local.description.notesProfessor Rainer Grun. This thesis has been made available through exception 200AB to the Copyright Act.
local.description.refereedYes
local.type.degreeDoctor of Philosophy (PhD)
dc.date.issued2005
local.contributor.affiliationThe Australian National University
local.identifier.doi10.25911/5d763a5e1b5c6
local.mintdoimint
CollectionsOpen Access Theses

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