Fungal community homogenization, shift in dominant trophic guild, and appearance of novel taxa with biotic invasion

Invasion by non-native plants may fundamentally restructure the soil fungal community. The invasive plant, Alliaria petiolata, produces secondary compounds suppressive to mycorrhizal fungi and may therefore be expected to have generally negative effects on other components of the fungal community. Here, we compared fungal biomass, diversity, community composition, and the relative abundance of fungal trophic guilds, along with edaphic properties of soils collected from uninvaded and invaded plots across six temperate forests. Invaded plots were differentiated from uninvaded plots by lower variation in fungal community composition (beta diversity) and soil properties, higher fungal richness and community evenness (alpha diversity), and a suite of novel saprotrophic and pathotrophic fungi that were consistently present across the invaded landscape and absent from uninvaded forest patches. Invaded plots also had lower ectomycorrhizal but higher saprotrophic and pathotrophic relative abundance, despite there being no difference in fungal biomass between invasion statuses. We hypothesize that shifts in the fungal community with invasion may directly impact plant disease response, soil nutrient cycling processes, and plant performance of the invasive and native plant communities.