Warming enhances the negative impact of shrubs on community stability via reducing species asynchrony

Abstract Numerous studies have demonstrated that climate warming and the presence of shrubs affect herbaceous plant community composition and function. However, how the temporal stability of herbaceous plant community biomass responds to combinations of warming and the presence of shrubs remains largely unexplored. The effects and mechanisms of simulated warming and shrubs on the community stability were investigated in a 5‐year field experiment in alpine grasslands. Our results showed that warming alone or shrubs alone reduced community stability by decreasing species richness and temporal asynchrony. Additionally, warming alone or shrubs alone reduced community stability by decreasing community‐weighted means of leaf dry matter content of species. We also found that the interaction of warming and shrubs had a cumulative negative effect on plant community stability by increasing species synchrony. Synthesis. Our study suggests that continued global warming and shrub expansion may negatively affect the stability of natural grassland functions and services, and highlights the importance of temporal asynchrony and traits among species in moderating the effects of global change on ecosystem stability.