Stochastic Process Dominates Microbial Community Assembly in Alpine Grasslands on the Tibetan Plateau

Abstract:

Our knowledge on biogeographical patterns and underlying mechanisms of microbial community assembly is crucial for predicting soil functions and their responses to global environmental change. However, previous studies mainly focused on bacteria and fungi in tropical and temperate ecosystems, little is known about the soil protist and animal community in alpine ecosystems. Based on a large-scale sampling of 147 sites collected from a 3500 km transect and 16S, ITS2 and 18S Hiseq sequencing, here we explored biogeographic patterns and underlying mechanisms of bacterial, fungal, protistan and soil animal community assembly in alpine grasslands on the Tibetan Plateau. We demonstrated that the species turnover of soil microbiota was rapid across alpine grasslands as revealed by steep distance-decay curves. Neutral community model and null model analysis showed the community assembly of soil microbiota were governed more by stochastic processes. Among four taxonomic groups, the bacterial and fungal community assembly were mainly driven by dispersal limitation, whereas protistan and soil animal community assembly were predominantly governed by ecological drift. These findings enhance our understanding of patterns and mechanisms driving community assembly of soil microbiota in alpine ecosystems, which provide a reference basis for predicting the dynamics of ecosystem functions under a changing environment.