Patterns of air temperature and accumulation of snow in subalpine heathlands and grasslands on the Bogong High Plains,Victoria

On well drained sites in the subalpine tract of the Bogong High Plains, Victoria, the distribution of grassland, dominated by Poa spp., and closed heathland, dominated by Prostanthera cuneata, can be correlated with patterns of maximum and minimum air temperature, and the accumulation and persistence of snow. Both maximum and minimum temperatures are lower, and the accumulation and persistence of snow is less in grassland, the dominant community of gentle slopes and hollows, than in closed heathland, the dominant community on steeper, leeward slopes. On gentle slopes and in hollows, the development of closed heath may be limited by the accumulation of cold air, relatively low temperatures and exposure to strong winds. However, on leeward slopes where snow persists the longest (until mid-late December), the development of heath may be limited by a shortening of the growing season. The distribution of grassland and heathland, especially the limits to the distribution of the heath, may also be affected by infrequent climatic events, such as the co-incidence of unusually low temperatures during winters when snow cover is meagre.