LAUSR

In many grasslands under grazing pressure, unpalatable plants have become abundant and these areas are refuges for plant diversity. We hypothesize that unpalatable plants may also serve as refuges for soil microbes. We tested this hypothesis by investigating soil fungal diversity and community composition, soil properties, and plant parameters in areas dominated by the unpalatable drunken horse grass (Achnatherum inebrians), and areas without this toxic grass, in three types of natural rangelands in northern China. Our results showed that the areas dominated by A. inebrians had a higher fungal diversity, higher microbial biomass, higher abundance of plant pathogens in soil, and higher plant biomass than areas that did not contain A. inebrians. Soil fungal community composition was positively correlated with plant community composition across the three study sites. Fungal diversity and microbial biomass were positively correlated with higher plant biomass. Abundance of soil plant pathogens was positively correlated with coverage of A. inebrians. The results indicated that plant community composition significantly correlated with soil fungal community composition, and refuge effects of A. inebrians drive higher fungal diversity, microbial biomass and abundance of plant pathogens in the soil. Increased abundance of A. inebrians potentially has considerable effects on the soil fungal community in grasslands.