Effects of invasive plant diversity on soil microbial communities

Abstract Native plant communities can be invaded by different numbers of alien plant species or by the same number of alien plant species with different levels of evenness. However, little is known about how alien invasive plant species richness and evenness affect soil microbial communities. We constructed native herbaceous plant communities invaded by exotic plants with different richness (1, 2, 4 and 8-species) and evenness (high and low) and analyzed soil physico-chemical properties and the diversity and composition of soil fungal and bacterial communities. Overall, species richness and evenness of invasive plants had no significant effect on bacterial and fungal alpha diversity (OTUs, Shannon, Simpson, Chao1 and ACE) and soil physico-chemical properties. However, invasive species richness had a significant impact on the relative abundance of the most dominant fungi Ascomycota and Bipolaris , and the dominant bacteria Actinobacteriota, which increased with increasing invasive species richness. The relative abundance of the dominant microbial groups was significantly correlated with the relative abundance of some specific invasive plant species in the community. This study sheds new light on the effects of plant co-invasion on soil microbial communities, which may help understand the underlying mechanisms of multiple alien plant invasion processes from the perspective of soil microorganisms.