Abstract/Summary

Aim The factors affecting community stability are important to understand as ecosystem function is increasingly at risk from biodiversity loss. Here we evaluate how a key factor - the position of local environmental conditions within the thermal range of the species - influences the stability of butterfly communities at a continental scale. Location Spain, UK, Finland Time-period 1999-2017 Major taxa studied Butterflies Methods We tested hypotheses about how species responses to temperature anomalies aggregate to influence stability: H.1 species have contrasting responses to local temperature anomalies at opposing edges of their thermal range; H.2 communities with central thermal range positions have higher community stability; impacts of thermal range position on community stability are driven by H.3 population asynchrony or H.4 additive population stability. Data are analysed at 876 sites for 157 species. Results We found some support for H.1 as there were interactions between thermal range and response to temperature anomalies such that species at different range edges could provide weak compensatory dynamics. However, responses were non-linear suggesting strong declines with extreme anomalies, particularly at the hot range edge. H.2 was partially supported as community stability increased with central thermal range positions and declined at edges, after accounting for species richness and community abundance. Thermal range position was weakly correlated with asynchrony (H.3) and population stability (H.4), though species richness and population abundance had larger impacts. Main conclusions Future extreme heat events will likely negatively impact species across their thermal range, but might be particularly impactful on populations at the hottest end of the thermal range. Thermal range position influenced community stability, as range edge communities were stable. However, predicting community stability from thermal range position is challenging due to non-linear responses to temperature with small temperature anomalies producing weak compensatory dynamics, but large extreme events synchronizing dynamics.