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 agricultural landscape during a phase of population increase. The primary aim was to determine whether spatial heterogeneity is an important consideration when examining population processes of mice. Mice within a 4-km2 trapping zone were trapped on approximately 36 transects at each of six farms on the Darling Downs, Queensland, in May and June 1992. There were 2100 trap-nights at each farm. Most mice were caught in undisturbed grass verges along fencelines. Undisturbed verges also harboured mice of above-average body condition and had the highest proportion of adult females breeding. High numbers of mice were caught also in roadside verges, long sorghum stubble and ripe summer crops. Few mice were caught in fallow paddocks, short sorghum stubble and ploughed 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 use by mice were significant at both a fine scale of habitat classification (seven habitat types) and a broader scale (four habitat types) more generally applicable to grain-growing regions in Australia. This study demonstrates that spatial heterogeneity needs to be considered when designing trapping protocols or control strategies for mice.