Is the altitudinal distribution of the Broad-toothed rat in Tasmania a result of the effects of Bennett's Wallaby?

The Broad-toothed Rat Mastacomys fuscus is infrequently recorded in Tasmania and was only recently discovered at altitudes >1000 m, although the species occurs on the Australian mainland at >2200 m. A survey of Tasmanian alpine habitat found evidence of M. fuscus within a metre or two of the summit of Cradle Mountain at 1545 m, the highest altitude recorded for M. fuscus within Tasmania. There was a negative relationship between the presence of Bennett's Wallaby (Macropus rufogriseus) and M. fuscus at all sites. This is analogous to the absence of tall alpine herbfield as a plant community in Tasmania as a result of grazing by M. rufogriseus. At Cradle Mountain, M. fuscus occurred in alpine areas above rock barriers that prevented access by M. rufogriseus and hence allowed sufficient growth of grass to support populations of M. fuscus.This study further demonstrates the importance of M. rufogriseus in alpine ecosystems that lack a seasonal snow cover and raises the question of the potential impacts of M. rufogriseus in habitats with declining snow cover in mainland alpine areas.