Interactions between soil microbes and native species drive a diversity-invasibility relationship

Soil microbes can affect both the invasiveness of exotic plants and the invasibility of native plant communities, but it still remains unclear whether soil microbes can influence the relationship between native plant species diversity and community invasibility. We constructed native plant communities with three levels of species richness (one, three, or six species) in un-sterilized or sterilized soil (i.e., with or without soil microbes) and let them not be invaded by exotic plant species or invaded by one of three exotic species (Solidago canadensis, Erigeron canadensis or Symphyotrichum subulatum) highly invasive in China. The soils conditioned by the native plant communities not invaded by the exotic species were used as soil microbe inocula to test whether richness-induced differences in soil microbes affect the growth of each of the three invasive species. Compared with the presence of soil microbes, the absence of soil microbes weakened the negative species richness-invasibility..., , Exp1: Colume D-M for plot with invasive species Solidago canadensis(SC)
          Colume N-W for plot with invasive species Erigeron canadensis(EC)
          Colume X-G for plot with invasive species Symphyotrichum subulatum(SS)
Exp2: Colume AH-AO