Characteristics of mammal communities in Tasmanian forests: exploring the influence of forest type and disturbance history

Abstract

Context With increasing pressure worldwide on forest habitat, it is crucial to understand faunal ecology to effectively manage and minimise impacts of anthropogenic habitat disturbance. Aims This study assessed whether differences in forest type and disturbance history were reflected in small to medium mammal communities found in Tasmania’s production forests. Methods Trapping was conducted in spring and summer, and autumn and winter during 2007–08 at four dry Eucalyptus forest sites (two regenerating after harvest and two in relatively undisturbed forest) in south-east Tasmania, and four wet Eucalyptus forest sites (two regenerating after harvest and two in relatively undisturbed forest) in north-east Tasmania. All sites were embedded within a matrix of mature or older aged regenerating forest. Key results Thirteen mammal species were recorded across all sites. There was no difference in species diversity or richness between forest type or disturbance regime, but species composition differed. Total number of individual animals and captures was influenced strongly by forest type and disturbance history, with most animals captured in the dry disturbed forest sites. Abundance of some species (e.g. bettongs and potoroos) was higher in disturbed sites than undisturbed sites. Brushtail possum numbers (adults and offspring), however, were lower in disturbed sites and populations displayed a male biased adult sex ratio and lower breeding frequency. Habitat structural complexity and vegetation diversity within core sites, and age structure of the forest in the surrounding landscape did not vary significantly, indicating that broad resource (food and refuge) availability was equivalent across sites. Conclusions In general, the small to medium mammals in this study did not appear to be significantly affected by forest harvesting in the medium term. Implications Although past harvesting altered the abundance of some habitat features (e.g. canopy cover, basal area of trees, and tree hollow availability), we suggest that the availability of such features in the surrounding landscape may mitigate the potential effects of disturbance on the species for which such habitat features are important.