Lichen species assemblage gradient in South Shetlands Islands, Antarctica: relationship to deglaciation and microsite conditions

Abstract

The glacier retreat in the Antarctic Peninsula is opening new ice-free areas and providing an excellent opportunity to study successional processes. Antarctic terrestrial ecosystems have the particular characteristic of being dominated almost exclusively by lichens and mosses. The aim of the present study was to analyze the diversity, cover and composition of a lichen community on a deglaciated gradient on Potter Peninsula, King George Island (maritime Antarctica), and to investigate how microsite variables influence these patterns. Total lichen cover, species richness, and the frequency and cover of lichens species were measured in five 50 × 50 cm grids in 24 sites covering the whole Peninsula from the coast to the glacier front. Microsite conditions were also registered: slope, aspect, and proportion of different substrates (rocks, soil or bryophytes). We recorded a highly diverse and complex lichen community arranged in three assemblages of species. The lichen communities showed clear variations along the studied gradient, related to the distance to the glacier, the slope, the type of substrate, and the interaction between them. We consider that the patterns of these Antarctic lichen communities are dynamic and very heterogeneous, since they depend on macroclimatic variables but there is also a strong influence of microsite factors.