Population dynamics of, and habitat use by, Austrlian native rodents in wet sclerophyll forest, Tasmania I. Rattus lutreolus velutinus (Rodentia : Muridae)

Abstract

A local population of velvet-furred rats, Rattus lutreolus velutinus, was studied for 15 months in wet sclerophyll forest in south-eastem Tasmania using mark-recapture techniques. Individuals in the trappable population were readily caught with 90% of captures being recaptures (73 individuals caught 706 times). During winter and the summer breeding season, all individuals had an equal likelihood of recapture, irrespective of sex, age, season or previous capture history. Habitat use was investigated by analysing floristic and structural variation within a 4-ha trapping grid using TWINSPAN. Four heterogeneous habitat groups were defined and population data are compared among these groups. Areas of densest ground cover were preferred by R. 1. velutinus; open areas were avoided. Throughout the study, female rats were captured in the areas with most cover to 50 cm in height; during winter, males were caught in areas of the trapping grid with more sparse ground cover, in lower numbers than females. At the onset of breeding in summer, numerous males were captured in the areas of thickest ground cover occupied by females. These data are discussed in relation to social spacing, habitat utilisation and female choice.