Extreme drought reduces climatic disequilibrium in dryland plant communities

High rates of climate change are currently exceeding many plant species’ capacity to keep up with climate, leading to mismatches between climatic conditions and climatic preferences of the species present in a community. This disequilibrium between climate and community composition could diminish, however, when critical climate thresholds are exceeded, due to population declines or losses among the more mismatched species. Here, we assessed the effect of an extreme drought event on rich semiarid shrubland communities in the south-eastern Iberian Peninsula. Using a community climate framework, we compared the community climatic disequilibrium before and after the drought episode on three study sites with different levels of precipitation. Disequilibrium was estimated as the difference between observed reference climate and community-inferred climate, calculated as the mean climatic optimum for the species present, weighted by their abundances. We found that extreme drought embedded wit...