Microclimates buffer the responses of plant communities to climate change

Abstract

Aim Despite predictions of high extinction risk from climate change, range expansions have been documented more frequently than range retractions, prompting suggestions that species can endure climatic changes by persisting in cool or damp microclimates. We test whether such ‘microrefugia’ exist. Location United Kingdom Methods We examine fine-scale changes in plant communities of a coastal grassland over a 30 year period in which spring temperatures increased by 1.4ºC. We examine whether changes in community composition and local colonisations and extinctions are related to microclimatic conditions. Results Our findings suggest that, while community reassembly was consistent with warming, changes were smaller on cooler, north-facing slopes. Closer inspection of patterns of species turnover revealed that species with low temperature requirements were able to persist on cooler slopes, while those with high moisture requirements suffered similar decreases in occupancy across all microclimates. Main conclusions Our results suggest that cooler slopes may act as microrefugia, buffering the effects of increases in temperature on plant communities by delaying extinctions of species with low temperature requirements.