Influence of environmental variables on mycorrhizal fungal diversity and function. Environmental factors impact the functional diversity of arbuscular mycorrhizal fungi (A), richness (B), phylogenetic diversity (C), and functional evenness (D) of ectomycorrhizal fungi. TC: total carbon; TN: total nitrogen; TP: total phosphorus; OM: organic matter; MBC: microbial biomass carbon; MBN: microbial biomass nitrogen; MBP: microbial biomass phosphorus; NO3._N: nitrate nitrogen; NH4._N: ammonium nitrogen; EC: electric conductivity; MC_F: fresh soil moisture content; MC_AD: air-dried soil moisture content; MAT: mean annual temperature; MAP: mean annual precipitation; CL: cellulase; UE: urease; SC: sucrase; ACP: acid phosphatase; β-GC: β-1,4-glucosidase; DHA: dehydrogenase; NAG: β-1,4-N-acetylglucosaminidase; β-XYS: β-xylosidase; LAP: Leucine aminopeptidase.