Natural and cultural histories of fire differ between Tasmanian and mainland Australian alpine vegetation

Abstract

We ask how and why mainland Australia and Tasmania differ in the natural and cultural history of alpine fire. Indigenous people seem unlikely to have extensively burned the alpine landscape in either of mainland Australia or Tasmania, whereas anthropogenic fire increased markedly after the European invasion. In Tasmania, where lightning ignition is uncommon, alpine fires have been rare post-1980, whereas mainland alpine vegetation has been extensively burned. The current distributions of the eight Australian alpine plant species that have no mechanisms for recovery from fire suggest that climate and natural fire barriers have been important in their survival. Mainland Australian pre-fire vegetation cover is typically attained in less than a decade, whereas in Tasmania, half a century or more after fire, bare ground persists at high levels, and continues to decrease only where mammalian herbivores are excluded. These differences appear to be ultimately related to the climatic contrast between the maritime mountains of Tasmania and the continental mainland mountains, through the effects of continentality on snow cover, which, in turn affect marsupial herbivore grazing, exposure of soil and vegetation to extreme microclimatic conditions and the degree of shrub dominance.