Driving Factors of the Dynamics of Microbial Community in a Dam of Copper Mine Tailings

Abstract

The relative importance of the deterministic versus stochastic processes underlying community dynamics has long been a central theme in community ecology, and is intensively debated in the field. Microbial communities play key roles in nutrient cycling and the flow of energy in ecosystems. The research on the structural dynamics of microbial community will provide data and theoretical support for understanding the assembly mechanisms of community, and for predicting the dynamics of microbial community under environmental stress. In this study, the Illumina MiSeq method was applied to investigate the structural dynamics of bacterial and fungal community in a dam of Shibahe mine tailings at different restoration stages (1-45 years). The results indicated that the soil physicochemical properties in the dam of mine tailings formed an ecological gradient, and the plant community showed succession along the restoration time. The diversity of plant communities was significantly correlated with soil nutrient contents but not with soil heavy metal contents. The structure of the microbial communities showed significant differences at different restoration stages of the dam land, in which Proteobacteria, Actinobacteria, Firmicutes, and Acidobacteria were the dominant bacterial phyla, and Ascomycota, Basidiomycota, and Zygomycota were the dominant fungal phyla. The assembly of the microbial community was shaped mainly by the soil nutrients and soil heavy metal contents, but plant diversity had no significant effect on the microbial community structure. It was suggested that edaphic factors drive the dynamics of microbial communities under the stress conditions of pH and heavy metals on small, local scales.