Tree mycorrhizal types and the interaction between tree and shrub species richness shape soil fungal communities in a subtropical forest in China

PurposeElucidating the interactions of above- and below-ground communities in forest ecosystems is of great importance for comprehending biodiversity maintenance and ecosystem functioning.MethodsIn the context of a Biodiversity and Ecosystem Functioning experiment conducted in China (BEF-China), we explored the combined effects of tree species richness (1, 2, and 4) and shrub species richness (0, 2, 4, and 8) on soil fungal community diversity and structure under tree species with different mycorrhizal types (i.e., arbuscular mycorrhizal (AM) tree and ectomycorrhizal (EM) tree) using the Illumina sequencing method.ResultsResults demonstrated that the fungal alpha diversity, community composition and network structure were significantly different between EM trees and AM trees. Although tree and shrub species richness had no significant interactive effect on soil fungal alpha diversity regardless of tree mycorrhizal types, however, their interactions did influence fungal community composition and co-occurrence network structure. Specifically, the interactive effect of tree and shrub species richness on soil fungal community composition was observed in AM trees, and their interactions affected the soil fungal co-occurrence network structure in EM trees.ConclusionsThese findings highlight the tree mycorrhizal type dependence of the interactive effects of tree and shrub species richness on soil fungal communities in a subtropical forest.