Herbivores in alpine herbfields: will wombats shift to higher altitudes with climate change?

Abstract

Shifts in the geographic range towards higher altitudes are anticipated for many species in south-eastern Australia in response to future climate warming. This is particularly the case for the Snowy Mountains, where a substantial reduction in the snow cover is expected to have a major impact on the distribution of species. A number of large marsupial herbivores occur at lower subalpine elevations, and a shift in their distribution to higher altitudes due to climate change will result in increased grazing of the vegetation of the alpine area. Common wombats Vombatus ursinus were chosen as a model species for examining range shifts because they are common in subalpine areas, but rarely occur above the tree line in the alpine zone. Changes in wombat habitat over time were predicted using a rule-based modelling approach that incorporates resources important to wombats as well as changes in snow depth with climate change. These models predicted a 16% increase in the area of suitable wombat habitat across the study area by 2050. This increase was largely within higher subalpine altitudes. Thus, shifts in wombat distribution in the Snowy Mountains with climate change are likely to occur at higher subalpine altitudes as a filling process within the extent of occurrence, rather than an expansion beyond the range boundary into the alpine zone.