<b>Interspecific and intraspecific trait variability differentially affect community functional composition responses to warming and altered precipitation</b>

Climate change may shift community functional composition by driving interspecific and intraspecific trait variability. However, their relative contributions in determining the community functional composition responses to climate change remain unclear. We conducted an 8-year field experiment in an alpine meadow to investigate how community functional composition responds to warming and altered precipitation, and disentangle the relative contributions of interspecific and intraspecific variability. Warming increased community height by promoting the growth of both short and tall plants. Notably, short plants exhibited greater variability in leaf functional traits than tall plants. Finally, intraspecific trait variability, species occurrence, species relative abundance, and their covariation collectively accounted for the changes in community functional composition under warming and altered precipitation. These results emphasize the necessity of distinguishing the role of intraspecific variability, species turnover, and functional groups in predicting the functional composition of alpine communities in a future climate.