Variation in the use of corridors by introduced and native rodents in South-Eastern Australia

We examined the use of roadside corridors as habitat by introduced and Australian native rodents using a replicated sampling program that compared their abundance in remnant forest, two types of roadside corridor and pasture. Introduced rodents were most abundant in either the corridors (black rat Rattus rattus) or in the corridors and pastures (house mouse Mus musculus), whereas forests were favoured by the native bush rat Rattus fuscipes. For all species, the density of different age-classes varied between the habitats. Additionally, there was interspecific and intraspecific (age-class) variation in the number of males to females in each habitat, and adult female bush rats in corridors weighed less than those in forests. These data indicate that some introduced species may be more prominent in corridors than native taxa, and highlight the importance of considering intraspecific as well as interspecific variation in corridor use when evaluating the role of corridors.