Summary
The RAPD technique (Random Amplified Polymorphic DNA) was used to assess the level of genetic diversity in Bryum argenteum from Ross Island and Southern Victoria Land, Antarctica. Samples were collected from three transects at different sites, and from several other geographically distinct populations within 150 km of Ross Island. Moss growth in two transects, sampled down small exposed meltstream channels at Cape Royds and Cape Chocolate, was very sparse with no other moss colonies found within several hundred metres. However, samples from these transects showed similar levels of genetic variation to those from a transect at Granite Harbour, where moss colonies were large, luxuriant and turf-like between boulders. In all transects, both within and between-clump variation was apparent, and some spatial relationships were observed down the length of the channels, with higher levels of variation at the top than the bottom of two transects. Samples from other sites in the region showed varying but high levels of genetic diversity; overall, the majority showed some clustering according to site of collection, with presumed transmission of propagules between sites. Evidence is presented for both short-distance dispersal by water, and long-distance dispersal by wind.