Stochastic processes dominate assembly of soil fungal community in grazing excluded grasslands in northwestern China

Purpose Soil microorganisms in grassland ecosystem exhibit varying spatial–temporal patterns. However, the underlying mechanisms shaping microbial community assembly during grassland restoration are largely unknown. Here, we assessed the relative importance of stochastic and deterministic processes in the assembly of soil fungal communities in a semiarid grassland during different grazing exclusion periods (i.e., 0, 20 and 40 years). Materials and methods The patterns of soil fungal communities were assessed using high-throughput genomic tools and multivariate statistical analyses. Results and discussion The mobility and alpha diversity of soil fungal communities peaked in grasslands where grazing had been excluded for 20 years, indicating that the soil fungal community had a higher dispersal ability and was more conducive to the increase of soil fungal community diversity. It was also noted that the soil fungal community compositions varied with grazing exclusion periods. However, Mantel tests, variance partitioning analysis (VPA), and hierarchical partitioning theory (HP) showed vegetation characteristics and soil properties had a small impact on soil fungal community compositions. The neutral community model (NCM), PER-SIMPER, and dispersal-niche continuum index (DNCI) highlighted that the formation of soil fungal community was primarily mediated by stochastic processes. Conclusions Taken together, the results of this research provided a better understanding of the spatial and temporal patterns of soil fungal communities and the mechanisms underlying soil fungal community assembly during the restoration process.