Different diversity mechanisms underlying drought resistance in native and invaded communities

Abstract The decline of global biodiversity and the increasing spread of invasive alien plants raise critical questions about how native species diversity and biological invasions interact to influence community resistance to disturbance, particularly global climate change. To explore the effects of native species diversity and biological invasions on community resistance to drought, we established experimental plant communities with varying species richness levels (1, 2, 4, 8 and 16 species), introduced the invasive species Symphyotrichum subulatum into half of these communities and then subjected all communities to no, moderate or intense drought. In both native and invaded communities, community resistance to drought was negatively correlated with biomass of the communities without drought, regardless of species richness. Additionally, lower biomass of the communities without drought was associated with smaller drought‐induced increases in root:shoot ratio, which in turn conferred higher community drought resistance. However, the mechanisms underlying drought resistance differed between native and invaded communities: changes in biomass triggered by complementarity effects positively determined drought resistance in native communities, but those triggered by selection effects governed drought resistance in invaded communities. Synthesis . These findings reveal distinct mechanisms governing drought resistance in native communities and those invaded by S. subulatum , offering valuable insights for managing the invasion of this species in the context of global climate change.