Studies of the ground-dwelling mammals of eucalypt forests in south-eastern New South Wales: The effect of environmental variables on distribution and abundance

We examined the distribution and abundance of ground-dwelling mammals in 13 areas within 500 000 ha of eucalypt forest in south-eastern New South Wales. Data are presented on the distribution and abundance of species in relation to three environmental gradient types involving nine variables: two direct gradients (temperature, rainfall); six indirect gradients (aspect, steepness of slope, position on slope, landform profile around the site, altitude, season) and a resource gradient (lithology). Many species of ground-dwelling mammal of the forests of south-eastern New South Wales were present along all gradients examined, although wide variation in abundance occurred for some species. Eight species were correlated with direct gradients and all species were correlated with at least one indirect gradient. There was wide variation in abundance and species diversity with lithology, but the variation was not related to nutrient status. Although variations in abundance occurred along environmental gradients, the composition of the ground-dwelling mammal fauna in south-eastern New South Wales forests changed little. A fourth gradient type, the substrate gradient (biomass of plants) appears to have the greatest effect, because in the shortterm, disturbances such as logging and fire play an important role. Disturbance can have a profound influence on the substrate gradient, but no influence on environmental gradients. The results are discussed in relation to the arboreal mammals and avifauna in the region and Environmental and Fauna Impact studies and forest management.