Warming impacts potential germination of non-native plants on the Antarctic Peninsula

The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming. Establishment and subsequent range expansion of non-native plants depend in part on germination ability under Antarctic conditions, but quantifying these processes has yet to receive detailed study. Viability testing and plant growth responses under simulated Antarctic soil surface conditions over an annual cycle show that 16 non-native species, including grasses, herbs, rushes and a succulent, germinated and continued development under a warming scenario. Thermal germination requirement (degree day sum) was calculated for each species and field soil-temperature recordings indicate that this is satisfied as far south as 72 degrees S. Here, we show that the establishment potential of non-native species, in number and geographical range, is considerably greater than currently suggested by species distribution modelling approaches, with important implications for risk assessments of non-native species along the Antarctic Peninsula. Stef Bokhorst et al. simulate a warming scenario in Antarctic soil under laboratory conditions and report the germination and growth of sixteen non-native plant species. These experimental results, combined with calculations of thermal germination requirement at +3 degrees C and +5 degrees C warming scenarios demonstrate that the risk of establishment by non-native species in Antarctica may be greater than previously suggested by species distribution modelling approaches.