Out of the freezer: The response of Continental Antarctic vegetation communities to climate change

Survival in Antarctica means enduring some of the harshest climatic conditions on Earth. Already at the edge of their physiological limits of survival, organisms are facing the current global threat of climate change, with higher latitudes strongly impacted. State of the Environment Indicator 72 monitors changes in fine scale vegetation community composition along a moisture gradient at two sites in the Windmill Islands, East Antarctica in order to model the potential long term impacts of climate change. This quantitative analysis of terrestrial vegetation communities, designed to minimise destructive sampling, commenced as a pilot in 2000 with full sampling in 2003, 2008 and 2013. Ten permanent quadrats are positioned within each of the bryophyte, transitional and lichen communities at both sites, with samples from each scored for presence/absence of each species. Changes in water availability, notably increased aridity in the bryophyte community and rising moisture content in the lichen community has corresponded with a shift in fine scale community composition. Favouring higher water content, the abundance of endemic moss species Schistidium antarctici has remained high in the wetter bryophyte community, whilst the more desiccation tolerant Ceratodon purpureus and moribund moss have increased in abundance within this community, supporting a drying trend in the region. Crustose lichens have decreased significantly within the intermediate transitional community; whilst the cosmopolitan moss Bryum pseudotriquetrum exhibits variability in abundance. These results suggest that if climate change leads to increased drying throughout the region, the endemic species S. antarctici will be most susceptible with C. purpureus colonising wetter communities.