The flora of the South Sandwich Islands, with particular reference to the influence of geothermal heating

• Published in: Journal of Biogeography
• Main Authors: Convey, P., Smith, R.I.L., Hodgson, D.A., Peat, H.P.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Blackwell 2000
• Subjects: Botany; Antarctic; The Antarctic; Sandwich Islands; South Sandwich Islands; Candlemas Island; Leskov Island; Bellingshausen Island; Antarc*; South Atlantic Ocean
• Online Access: http://nora.nerc.ac.uk/id/eprint/20466/; https://doi.org/10.1046/j.1365-2699.2000.00512.x

Aim To carry out as comprehensive a survey as practicable of the flora (higher plants, mosses, liverworts, lichens, basidiomycete fungi and diatoms) of the isolated, volcanically active, South Sandwich Islands archipelago in the southern South Atlantic. To relate the components of this flora to (1) the influence of local geothermal heating and (2) wider regional floras. Location South Sandwich Islands, southern South Atlantic Ocean, maritime Antarctic (56–60° S, 26–28° W). Methods Ice-free accessible sites on all 11 of the major islands in the archipelago were visited by helicopter in January 1997. During each visit, voucher specimens of each floral group were collected. The comprehensiveness of collections obtained at each site varied with the duration of each visit (a function of tight logistic constraints) and extent of site. Visit duration varied from 1 to 9 h at most sites, with longer periods spent on Bellingshausen Island (2 days) and Leskov Island (1 day). Candlemas Island was examined in greater detail over a 4-week period in February 1997. At all sites, particular attention was given to areas influenced by geothermal heating. Results Data obtained in 1997 are combined with updated records from the only previous survey (in 1964) to provide a baseline description of the flora of the archipelago, which currently includes 1 phanerogam, 38 mosses, 11 liverworts, 5 basidiomycete fungi, 41 lichenised fungi and 16 diatoms with, additionally, several taxa identified only to genus. Major elements of the moss and liverwort floras are composed of South American taxa (32% and 73%, respectively), with a further 45% of mosses having bipolar or cosmopolitan distributions. These two groups show low levels of Antarctic endemicity (11% and 18%, respectively). In contrast, 52% of lichens and 80% of basidiomycete fungi are endemic to the Antarctic. A further 36% of lichens are bipolar/cosmopolitan, with only 5% of South American origin. Main Conclusions The flora of the South Sandwich Islands is clearly derived from those ...