Vegetation of the alpine sand dunes at Lake Augusta, Tasmania

Abstract

Alpine sand dunes are a rare phenomenon. On the Central Plateau of Tasmania parabolic dunes occur on the leeward of glaciofluvial lakes. The largest such complex is at Lake Augusta where seven sand dune communities and two slack communities were recognized from a sorted table produced by a polythetic divisive classification of floristic data. Fen was found on the rocky parts of the lake shore, while short alpine herbfield (‘marsupial lawn’) occurred in seasonally inundated slacks. Freshly mobilized sand had distinct shrubland communities, two of which exclusively occupied the fresh sand of the foredunes, while one occurred on remobilized older soils. Three communities formed a toposequence on the older soils of the well-drained dunes. Zonation was not strong beyond the foredune. Species richness and height generally increased inland. The older soils were more nutrient rich than the younger sands, a phenomenon probably attributable to the ultimate igneous origin of the material. The dunes have considerable conservation significance. Activities that could cause further mobilization need to be restricted.