Variation in soil microbial communityand its mechanisms along an elevation gradient in the Qilian mountains, China

Untangling the multiple drivers that affect biodiversity along elevation gradients is crucial for predicting the consequences of climate change on mountain ecosystems. However, the distribution patterns of microorganisms along elevation gradients have not yet been clarified, in particular when associated to strong changes in dominant species. Five typical vegetations (i.e., coniferous forest, meadow grassland, alpine shrub, alpine meadow, and sparse vegetation of limestone flats) from contrasting vegetation belts were selected to explore the influence of elevation gradients on soil microbial communities. The results showed that Actinobacteriota and Proteobacteria were the dominant bacterial phylum. Ascomycota and Basidiomycota were the prevalent fungal phylum. Soil bacterial alpha diversity increased with increasing elevation, while soil fungal alpha diversity showed an obvious mid-elevation pattern. The beta diversity of bacterial and fungal communities reflected a clear spatial niche-differentiation, and indicated that herbaceous plants affected soil bacterial communities while shrubs preferred soil fungal communities. Correlation analysis showed that environmental factors had different contributions to the composition and diversity of soil microbial communities. Soil bacteria were primarily affected by soil properties whereas fungi were affected by vegetation. Our results can improve the prediction of soil microorganism ecological processes and patterns as related to elevation and provide a theoretical basis for soil microbial prediction in the context of global change.