Resilience of Collembola communities to extreme drought is moderated by land use at a regional scale

In a world undergoing climate and usage change, soil biodiversity, which accounts to 25 % of the terrestrial biodiversity, is under severe threats. However, scenarios of climate change are based on known sensitivity of aboveground communities while there are differences on the responses to these changes with soil biodiversity. Here, we investigate the effects of an extreme climatic – due to an exceptionally drought year in 2011 - in various land use types (grassland, arable land, forest) through a study conducted at a regional scale (146 sites in Meuse, France) during 5 years. We characterized the responses of Collembola communities to climate change using (i) taxonomic indices and species dynamics, and (ii) species' functional traits and trait-based indices to reveal community assembly mechanisms. Our results demonstrated a total of 98 Collembola species collected during the five year project over the three land uses. Density and species richness were modulated by year, by land use and by their interaction. Three different distribution patterns in response to extreme drought events were demonstrated according to land use. Our findings thus reveal various effects according to land use, with a fast recovery of communities in arable lands, a long term effect for grasslands, and almost no effects observed in forests. These results show that the diversity of Collembola communities may be used as indicators of the resilience of ecosystems facing extreme climatic events.