Long term effects of Lespedeza bicolor revegetation on soil bacterial communities in Dexing copper mine tailings in Jiangxi Province, China

Soil microbial communities are important for ecological restoration and succession on mine tailings. In the present study, we performed Illumina sequencing to investigate the effects of long term Lespedeza bicolor revegetation on bacterial diversity and community structure in mine tailings under subtropical and moist climatic conditions. Microbial diversity indices (Shannon, OTU number and coverage estimator) of the revegetated soils were higher than that of the control, and increased over sampling period compared to the decreased pattern in the control. Species within known acid tolerant and nutrient regulated genera dominated both revegetated tailings and the control, and exhibited more abundant in the revegetated tailings. At the phylum level, percentage of the Proteobacteria and Actinobacteria were remarkedly higher in revegetated tailings than that in the control, while Chloroflexi performed reversely. Overall, this study found the positive role of L. bicolor revegetation in bacterial diversity development in the acidic mine tailings. Furthermore, the 30-year L. bicolor revegetation made the microbial community structure more homogenizable as a decrease of dissimilarity in tailings was identified over sampling times. Redundancy analysis at the OTU level indicated that Olsen-P and pH were the main regulators of microbial composition, suggesting that soil P and pH are determinant for ecological restoration and microbial community development in acidic mine tailings.