Microhabitat use by the long-nosed potoroo, Potorous tridactylus, and other small mammals in remnant forest vegetation, south-western Victoria

Abstract

Microhabitat use by the long-nosed potoroo, Potorous tridactylus, and six other species of small mammal was studied in remnant forest vegetation in south-western Victoria, Australia. Throughout its geographic range, P. tridactylus is consistently associated with dense vegetation in the ground and shrub strata. However, at a local scale, captures of P. tridactylus were not clearly associated with a particular floristic group, and were not strongly correlated with any structural feature of the vegetation. Rather, individuals utilised a range of sites of differing floristic composition and vegetation density. Dense cover provided diurnal shelter and protection from predators, whereas food resources were most abundant in adjacent more open areas. The use of vegetation mosaics or ecotones that allow the inclusion of contrasting microhabitats within an individual home range appears to be characteristic of potoroids in temperate environments. Such mosaics may result from topographic or edaphic variation, or from sera1 successional stages in vegetation following disturbance. Of the other small mammals, the bush rat, Rattus fuscipes, and the brown antechinus, Antechinus stuartii, favoured floristic groups that provided dense low cover. Captures of the swamp rat, Rattus lutreolus, were clumped, and centred on several sites along the forest edge on impeded drainage where potential foods were common. The long-nosed bandicoot, Perameles nasuta, and the southern brown bandicoot, Isoodon obesulus, were uncommon and clear microhabitat preferences were not displayed. The house mouse, Mus musculus, was of transient occurrence, mostly during autumn, and no obvious habitat preference was apparent. The quality and availability of microhabitats in remnant vegetation, together with landscape structure, are important in ensuring the persistence and conservation of small mammals in fragmented landscapes.