Nitrogen deposition enhances the competitive advantage of invasive plant species over common native species through improved resource acquisition and absorption

Abstract

Background Previous studies into the interactions between native and invasive species under nitrogen (N) deposition have often overlooked the presence of co-occurring native species, a factor that could influence the outcomes of interspecific competition. Furthermore, publication bias may lead researchers to focus on rare native species with limited adaptability. In this study, we examined how two levels of N deposition affected the physiological and ecological traits and the interspecies interactions between three invasive and three common native species. Results N deposition promoted the growth of both invasive and native species. The relative dominance index (RDI) of invasive species was consistently higher than that of native species. Invasive species had an advantage over common native species in using the increased N effectively. The biomass distribution of invasive species was biased toward the aboveground parts, indicating competition for light resources. Conclusions N deposition conferred a stronger competitive advantage to invasive species than to native species, suggesting that the distribution range of invasive species may expand further under increased N deposition.