Modelling distributions of arboreal and ground-dwelling mammals in relation to climate, nutrients, plant chemical defences and vegetation structure in the eucalypt forests of southeastern Australia
Cork, SJ & Catling, PC 1996, Forest Ecology and Management, vol. 85, pp. 163-175.
This paper reviews numerous studies investigating how both arboreal and ground-dwelling mammal distributions respond to changes in climate, leaf nutrients, plant chemical defences and vegetation structure, using the temperate Eucalyptus forests of southeastern and northeastern New South Wales as case studies.
The authors found that for both groups of mammals, the quality of habitat and nutritional status of eucalypt forests are prime factors determining distribution. For arboreal species, including the koala, sufficient nutrient quality of foliage was the principal factor in determining species presence. Variables related to the structural characteristics or habitat complexity of forest were also found to correlate with mammal distributions but were more directly related to the presence of ground-dwelling mammals than arboreal. For both groups, climatic and terrain variables were not found to provide sufficient information about habitat requirements at the small scales necessary for conservation efforts. The authors suggest that in order to produce significant, reliable results from models, studies must sample an adequate proportion of the population, and achieve baseline data for each variable such as habitat complexity or nutritional foliage information in forests to then accurately compare variations and determine how these may affect species distributions. The collected data needs to take into account factors such as gradients in seral stages or the intermediate stages of ecological succession as well as the disturbance history to help stratify surveys on these related gradients.
Although this study does not specifically focus on the koala, the results highlight the importance of collecting adequate data relating to variables that may affect the distribution of the species. The success of modelling koala distributions will be determined by the quality of quantity of data collected, particularly related to leaf nutritional quality as this was determined to be a prime factor in arboreal mammal species distributions. Accurate modelling of koala distributions is necessary to predict and define habitat requirements to inform koala conservation efforts.
Summarised by Robyn Boldy
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