Population and Habitat Characteristics of the Golden Bandicoot (Isoodon Auratus) on Marchinbar Island, Northern Territory.

Abstract

The presence of the golden bandicoot (Isoodon auratus) on Marchinbar Island off north-eastern Arhemland, Northern Territory, was confirmed by means of morphological features, hair characteristics and allozyme electrophoresis. Evidence of I. auratus was found at most points sampled along the 50-km length of Marchinbar Island. The species showed a strong habitat preference for low heath or shrubland on sand or sandstone, a combination that covers some 70% or 140 km2 of the island. No sign was found in the remaining forest/thicket or strand/Casuarina habitat. No major changes occurred in the distribution of the species between seasons, and individuals maintained overlapping home ranges of similar size, about 10-35 ha. Considerable variation occurred in the characteristics of sites used for daytime shelter, including rocky shelves, shrubs and Triodia hummocks. Different shelter sites were frequently occupied on consecutive days. Foraging sites were sparsely vegetated and diet consisted mainly of a broad range of invertebrates. It is likely that the rocky habitat of Marchinbar Island is sufficiently dissected to ensure the availability of suitable habitat without the necessity of a managed fire regime. The bandicoot population on Marchinbar Island has at least two terrestrial predators, wild dogs (Canis familiaris) and carpet pythons (Morelia spilota). The current predation pressure is not considered to threaten the existence of the bandicoots on the island; however, the addition of another predator species (e.g. the feral cat) may create unacceptable conditions.