The bryophyte flora of geothermal habitats on Deception Island, Antarctica
Deception Island is one of the most volcanically active sites south of 60°S. Between 1967 and 1970 three major eruptions devastated large expanses of the landscape and its predominantly cryptogamic vegetation. Since 1970 extensive recolonisation has occurred on the more stable surfaces. Unheated ground supports several bryophyte and lichen communities typical of much of the maritime Antarctic, but geothermal habitats possess remarkable associations of bryophytes, many of the species being unknown or very rare elsewhere in the Antarctic. Nine geothermal sites were located and their vegetation investigated in detail. Communities associated with more transient sites have disappeared when the geothermal activity ceased. Mosses and liverworts occur to within a few centimetres of fumarole vents where temperatures reach 90-95°C, while temperatures within adjacent moss turf can reach 35-50°C or more and remain consistently between 25 and 45°C. Most of the bryoflora has Patagonian-Fuegian provenance and it is presumed that, unlike most species, the thermophiles are not pre-adapted to the Antarctic environment, being able to colonise only where the warm and humid conditions previal.