Temperature, not precipitation, is the dominant assembly filter in dryland plant communities

Biotic responses to limited and variable precipitation contribute to ecological dynamics in drylands. However, the nature of those responses may be strongly constrained by long-term temperature conditions. Using several lines of evidence, we demonstrate that temperature is a more intense and consistent community assembly filter across drylands of the Southwest USA, and in turn how interactions between frost, heat, and drought tolerance strategies may alter plant responses to temporal variation in precipitation. We conclude by discussing implications for biotic responses to environmental change.