Genetic diversity and dispersal of the moss Sarconeurum glaciale on Ross Island, East Antarctica

The extent of genetic variation and dispersal mechanisms were investigated over short distances of 1-100 m, and up to 3 km, by the random amplified po lymorphic DNA (RAPD) technique, for the moss Sarconeurum glaciale, at three locations on Ross Island, Antarctica. At Arrival Heights, genetic variatio n occurred within single colonies, and the relationships between clumps ind icated that they were dispersed down small, meltwater drainage channels by water. The genetic similarities between the colonies from Arrival Heights a nd others from Scott Base and Crater Hill, a few km away, together with the prevailing wind direction and absence of this moss in the intervening snow -covered area, suggested longer-distance dispersal by wind. Overall, the Ro ss Island samples appeared to form a single, polymorphic population that wa s distinct from another population at Canada Glacier, 110 km distant. Somat ic mutation, rather than immigration of genetically different propagules fr om elsewhere, appeared to be the most probable cause of genetic variability in these haploid, vegetatively reproducing Antarctic moss populations, Ini tiation of recolonization of S. glaciale across a dirt track at Arrival Hei ghts was also investigated by RAPDs, to investigate how regrowth of mosses in disturbed areas occurred in the extreme environment of Antarctica.