Climate and animal distribution: a climatic analysis of the Australian marsupial Trichosurus caninus

Aim: A detailed bioclimatic analysis was completed for an Australian arboreal marsupial, the mountain brushtail possum Trichosurus caninus. This was done to explore climatic factors underpinning the distribution of the species. Location: Location data used for bioclimatic modelling comprised of 879 records, covering the entire known range of T. caninus throughout eastern Australia. Methods The computer package BIOCLIM was used to generate a bioclimatic profile of T. caninus. Frequency distributions of climatic attributes in the profile were examined using histograms and a pattern analysis (using the computer package PATN) to determine if there were bioclimatically distinct groups of possums. Results: Initial analyses of bioclimatic attributes of all records split the location data into two discrete groups based on the frequency distribution of 'mean temperature of the wettest quarter' of an average year, as this had a discontinuous, bimodal frequency distribution. Pattern analysis produced groupings congruent with this. When analysed separately, the bioclimatic domains of the two groups were geographically discrete. Although many key bioclimatic attributes were similar (particularly those defining light and moisture regimes that relate to vegetation structure), temperature regimes and seasonality of rainfall regime were very different for each group. Main conclusions: The two groups identified in this study were congruent with two groups established by an earlier multivariate morphometric analysis of T. caninus. Further targeted field research together with genetic analyses, are needed to further investigate the taxonomic significance of findings on (1) the bioclimatic domain(s) and (2) the morphology of T. caninus.