Summary
Natural variability in surface reflectance was studied in 3 species of moss (Grimmia antarctici, Bryum pseudotriquetrum and Ceratodon purpureus) in continental Antarctica. The moss community is well developed in Wilkes Land, eastern Antarctica, but it is restricted to locations where free water is available for at least some summer months. Antarctica is experiencing large increases in incident UV-B radiation due to reductions in stratospheric ozone. Additionally over the summer months levels of visible solar radiation are also high, increasing the likelihood of photoinhibitory damage in moss plants. The aim of this study was to describe the natural variability in the surface reflectance characteristics of moss, to obtain a baseline with which to assess future changes in response to global climate change, and imposed experimental treatments, and also to develop hypotheses with respect to how mosses have adapted to the cold and arid antarctic environment. Variability in surface reflectance was assessed over changes in microtopography of moss turves, over species, visual coloration and when moss was wet, dry or frozen. In addition concentrations of photosynthetic and UV-absorbing pigments were measured and related to whole plant reflectance. Surface reflectance characteristics of moss were sensitive to species, site, microtopography and environmental conditions. Pigment concentrations were also different among species and were influenced by environmental conditions, particularly water availability and UV and visible radiation. Correlations between pigment concentrations and reflectance indices will be described. The results suggest that the endemic species, G. antarctici, is likely to be the most sensitive to future climate change.