Sexual Differences in Habitat Use by Rattus lutreolus (Rodentia: Muridae): The Emergence of Patterns in Native Rodent Community Structure.

Abstract

The successful long-term conservation of Australian fauna relies on a clear understanding of how coexisting species partition limited resources. Such partitioning results in complex levels of habitat selection, dependent on dynamic interactions between biotic and abiotic processes. In small mammal communities where native Rattus spp. are present and there are substantial interspecific competitive effects, habitat selection by female Rattus may drive habitat use by other rodent species (particularly native mice). This has been demonstrated in Tasmania where the velvet-furred rat, R. lutreolus velutinus, and the long-tailed mouse, Pseudomys higginsi, occupy wet sclerophyll forest in sympatry. Differential habitat use is exhibited by male and female R. l. velutinus which may determine the extent of habitat use by P. higginsi. Here, I report a similar pattern of coexistence between the swamp rat, R. l. lutreolus, and the eastern chestnut mouse, P. gracilicaudatus, in coastal heathland in New South Wales. As in the Tasmanian model, female R. l. lutreolus were significantly more likely to be trapped in areas of densest vegetation, and male R. l. lutreolus and both sexes of P. gracilicaudatus were more often trapped in areas where cover was less dense. This finding introduces the possibility that there exists a clear and possibly widespread mechanism of coexistence that involves intersexual differences in habitat use by the dominant species in communities where substantive interspecific competition has been demonstrated.