The nature of the transition from sedgeland to alpine vegetation in South West Tasmania: I. Altitudinal vegetation change on four mountains

The results of contemporary research suggest that vegetation varies continuously with environment, except where dominants create new habitats. However, phytosociological and distributional data from the treeless parts of mountains in the south-west of Tasmania indicate the existence of a sharp vegetation boundary at 700-900 m above sea level, despite an apparent climatic, geologic, edaphic and topographic continuity of environment. This boundary cannot be attributed to the interactions between species, because it occurs within sparsely vegetated gravel as well as within continuous vegetation cover on peat. The boundary might have originated as a result of the local extinction of lowland species during the climatic vicissitudes of the Quaternary. However, there is a possibility that the boundary correlates with a persistent cloud ceiling, and more climatic data are needed from the region before historical explanations become necessary.