Warming reduces the compositional and biomass stability of alpine meadows via declines in species richness and functional dispersion

Understanding the mechanisms that maintain grassland community composition and biomass stability is crucial for the functions and services provided by ecosystems under climate change, and the development of grassland management and restoration strategies. However, how the potential mechanisms of warming and altered precipitation combine to affect community compositional and biomass production stability are still not clear, especially in alpine ecosystem. Here, we conducted a 4‐year field experiment to manipulate warming and precipitation alteration in an alpine meadow on the eastern Tibetan Plateau to investigate how climate change affects the temporal stability of plant community composition and biomass. We showed that warming alone decreased community biomass stability, and it combined with precipitation alteration decreased compositional stability, respectively, while precipitation alteration alone had no significant effect. The effect of warming on community compositional and biomass stability was influenced by precipitation change. Warming reduced community compositional and biomass stability by decreasing functional dispersion, while precipitation addition and reduction will alleviate and exacerbate the negative effects of warming on community composition and biomass stability by influencing species richness. Moreover, biomass stability is largely determined by asynchrony among species. Our results suggest that climate warming and combined with precipitation alteration would reduce alpine community compositional stability primarily by reducing functional dispersion and species richness, and reduce the stability of community biomass via decreasing compositional stability. Thus, our findings provide valuable information for the sustainable functioning of grassland maintenance, highlighting that future grassland conservation and management should consider increasing species and functional diversity to mitigate or recover the negative impacts of climate warming on alpine plant community composition and biomass stability.