Phytogeographical analysis of Tasmanian alpine floras

Abstract

List of vascular plant species were obtained from twenty-eight, disjunct, high altitude, treeless areas in Tasmania. These list pertained to vegetation dominated by the austral-montane element of the flora which is found both above and below the usually indistinct, and often absent, Tasmanian upper slope treeline. A polythetic, agglomerative classification of the Tasmanian and four Australian mainland alpine floras resulted in five groups: the mainland mountains, the eastern Tasmanian mountains, a group extending north-south through the centre of Tasmania, western Tasmanian quartzite mountains, and western Tasmanian mountains formed from more weatherable parent material. The Tasmanian floras form a continuum closely related to mean annual precipitation and surface geology, but not strongly related to continentality. Tasmanian endemism increases strongly from east to west, and similarity values with the mainland mountain floras and the New Zealand flora show the reverse pattern. It is suggested that the variation in and between the alpine floras of Tasmania and mainland Australia may be largely related to edaphic conditions