Netherlands Polar Data Center

Climate change impact on Antarctic terrestrial communities is often context-dependent, and our understanding of changes is currently based on a limited number of studies across different locations and ecosystems. Here we compare the response of two dominant vegetation types in the Maritime Antarctic, a Sanionia-Brachythecium moss association and an Usnea lichen fellfield community, over 22 years of experimental warming using open top chambers (OTCs) and control plots on Anchorage Island (67°61’ S 68°22’ W, southern Maritime Antarctic). No measurable moss community changes were detected in the control plots, while Sanionia uncinata displaced Brachythecium austrosalebrosum in the OTCs. Moss photosynthesis was 36% lower in the OTCs compared to control plots and infection by fungal ‘fairy rings’ was on average three times more frequent in OTCs. Microarthropod populations present in the moss showed large interannual variation and, while the Collembola community did not respond to warming, Acari abundance was on average 64% lower in OTCs compared to control plots. Within this group, numbers of the oribatid mite, Halozetes belgicae, were 79% lower in OTCs while prostigmatid mites were on average nine times more abundant. In the lichen plots, total cover dropped from ~90% to ~25% during the first 10 years of warming, and Usnea antarctica and Umbilicaria decussata disappeared. The lichen plot OTCs were destroyed by stormy weather at this point, although the plots remained marked.  The open lichen community was subsequentially colonized by Buellia species, and total lichen cover doubled within 11 years, thereby resetting the initial stages of lichen succession. The long-term and frequent monitoring achieved in this study has allowed us to track linear and non-linear changes in these communities under warming, and the continuation of such assessments is vital to capture future changes as strong trends of climate change are predicted to continue in this part of Antarctica.

Study impact of climate change on Antarctic communities