The terrestrial biota of Charcot Island, eastern Bellingshausen Sea, Antarctica: an example of extreme isolation

This paper documents the previously undescribed terrestrial fauna (mites, n ematodes, tardigrades) and flora (liverworts, mosses and lichens) of Marion Nunataks, Charcot Island (69 degrees 45'S 075 degrees 15'W). Species diver sity in all groups is low relative to other Maritime Antarctic sites, proba bly a twin function of very limited ice-free terrain and extreme isolation. The fauna and flora are wholly immigrant and, with the exceptions of two l ichens (Psilolechia lucida and Umbilicaria aff. thamnodes), clearly derived from the Maritime Antarctic. The fauna is unique for the Maritime Antarcti c in that it appears to contain neither predatory arthropods nor Collembola (springtails), which are otherwise ubiquitous and important members of the terrestrial fauna of the zone. The flora includes exceptional development of three mosses that are encountered only rarely at latitudes south of c. 6 5 degreesS, Brachythecium austrosalebrosum, Dicranoweisia crispula and Poly trichum piliferum. The southern limit for several mosses and lichens has be en extended. This small and isolated site is extremely vulnerable to accide ntal human-mediated introduction of both native Antarctic and alien biota.