Increased precipitation magnifies the effects of N addition on performance of invasive plants in subtropical native communities

Abstract

Abstract Aims Nitrogen (N) deposition, precipitation and their interaction affect plant invasions in temperate ecosystems with limiting N and water resources, but whether and how they affect plant invasions in subtropical native communities with abundant N and precipitation remains unclear. Methods We constructed in situ artificial communities with 12 common native plant species in a subtropical system and introduced four common invasive plant species and their native counterparts to these communities. We compared plant growth and establishment of introduced invasive species and native counterparts in communities exposed to ambient (CK), N addition (N+), increased precipitation (P+) and N addition plus increased precipitation (P+N+). We also investigated the density and aboveground biomass of communities under such conditions. Important Findings P+ alone did not enhance the performance of invasive species or native counterparts. N+ enhanced only the aboveground biomass and relative density of invasive species. P+N+ enhanced the growth and establishment performance of both invasive species and native counterparts. Most growth and establishment parameters of invasive species were greater than those of native counterparts under N+, P+ and P+N+ conditions. The density and aboveground biomass of native communities established by invasive species were significantly lower than those of native communities established by native counterparts under P+N+ conditions. These results suggest that P+ may magnify the effects of N+ on performance of invasive species in subtropical native communities where N and water are often abundant, which may help to understand the effect of global change on plant invasion in subtropical ecosystems.