Strategies of survival and resource exploitation in the Antarctic fellfield ecosystem.

Antarctic fellfields present organisms with a heterogeneous habitat characterised by a wide variety of environmental stresses. These include low temperatures, limited moisture availability, frequent and often rapid freeze-thaw and hydration-dehydration cycles, exposure to high photosynthetic photon flux density and ultraviolet (uv) irradiance, seasonal snow cover, high winds, cryoturbation and, depending on location south of the Antarctic Circle, considerable daylight in summer. Most of these factors vary both predictably and unpredictably in spatial and temporal planes.

Non-destructive analysis of pigments and other organic compounds in lichens using Fourier-transform Raman spectroscopy: a study of Antarctic epilithic lichens.

Lichens in Antarctic habitats are subjected to environmental extremes, including UVB radiation, desiccation and low temperatures, as well as to rapid fluctuations in these. Lichens synthesise a variety of chemical compounds in response to their environmental conditions which contribute towards their colour, and which act as protectants against physiological stresses. The fluorescence generated by the lichens at 532 nm can be used in epifluorescence microscopy to identify their presence on substrata but this can severely affect the Raman spectra using visible excitation.

Introduced reindeer and their effects on the vegetation and the epigeic invertebrate fauna of South Georgia (subantarctic).

The introduced reindeer of South Georgia have had a serious impact on the vegetation throughout the range of three populations on the island. Exclosure experiments in areas where the reindeer were introduced have resulted in a dramatic change in the composition of the protected vegetation. Poa flabellata (the major winter food) and Acaena magellanica (a major summer food) have recovered to their former status inside the exclosures, while Deschampsia antarctia and the introduced grass Poa annua tolerate grazing and trampling and have spread over the grazed areas.