Linear roadside remnants: Their influence on den-use, home range and mating system in bobucks (Trichosurus cunninghami)

Abstract

Forest clearance results in a marked change in the dispersion of resources such as food and shelter: from a relatively continuous distribution, to patches and strips of remnant habitat set in a more or less inhospitable matrix. Such changes in the patterns of resource dispersion have the potential to strongly influence the dynamics of social and mating systems of resident animal populations. We studied the den-use patterns, home range characteristics and mating system of a population of bobucks, Trichosurus cunninghami (Marsupialia: Phalangeridae), permanently resident in linear roadside strips of vegetation in north-eastern Victoria, Australia in order to gain a greater understanding of the impacts of occupying linear roadside habitats on the behavioural ecology of arboreal marsupials. We radio-tracked 11 adult females and six adult males and collected 2126 diurnal fixes (mean 125/individual) and 1044 nocturnal fixes (mean 61/individual). Males used significantly more den-trees (mean 16.5 ± 1.5 den-trees/individual) than females (mean 7.4 ± 0.6 den-trees/individual) and had home ranges more than twice the size of those of females (male mean 5.1 ± 0.8 ha, female mean 2.1 ± 0.3 ha). On average, each male's home range overlapped with those of three females; there was little intrasexual home range overlap in either sex. Genetic parentage analysis of all young sampled during the study (n = 22) established that only males that overlapped in home range with females had sired those females' young. All but one male in the study sired multiple young in each of the years they were recorded breeding. These behavioural and genetic data indicate that the roadside population was polygynous, in contrast to the socially monogamous bobuck population we studied in a neighbouring forest patch. These differences in behaviour may reflect patterns of resource distribution in the two habitats.