SPATIAL HETEROGENEITY IN WILD POPULATIONS OF HOUSE MICE (MUS-DOMESTICUS) ON THE DARLING-DOWNS, SOUTH-EASTERN QUEENSLAND

This study examined habitat use by house mice (Mus domesticus) in an a gricultural landscape during a phase of population increase. The prima ry aim was to determine whether spatial heterogeneity is an important consideration when examining population processes of mice. Mice within a 4-km(2) trapping zone were trapped on approximately 36 transects at each of six farms on the Darling Downs, Queensland, in May and June 1 992. There were 2100 trap-nights at each farm. Most mice were caught i n undisturbed grass Verges along fencelines. Undisturbed verges also h arboured mice of above-average body condition and had the highest prop ortion of adult females breeding. High numbers of mice were caught als o in roadside verges, long sorghum stubble and ripe summer crops. Few mice were caught in fellow paddocks, short sorghum stubble and ploughe d sorghum stubble. Habitat use did not vary with sex or age-class. The distribution of mice amongst habitats varied at each farm. Thus, over the two months there were farm-level differences in how mice used the landscape in this agricultural system. These variations in habitat us e by mice were significant at both a fine scale of habitat classificat ion (seven habitat types) and a broader scale (four habitat types) mor e generally applicable to grain-growing regions in Australia. This stu dy demonstrates that spatial heterogeneity needs to be considered when designing trapping protocols or control strategies for mice.