Soil bacterial communities with an indicative function response to nutrients in wetlands of Northeastern China that have undergone natural restoration

Abstract

Natural restoration is an important process in terrestrial systems, playing an essential role in enhancing soil quality and biodiversity. Bacteria are a vital part of the ecosystem and have many functions in wetlands, driving the decomposition of soil organic matter and plant litter. However, the role of soil bacteria in natural restoration has not been well understood, particularly in wetlands with anthropogenic disturbance (were changed into paddy fields). In this study, we investigated the soil physicochemical properties and soil bacterial communities in paddy fields, wetlands that have undergone natural restoration, and natural wetlands in the Tumen River Basin, Northeastern China. The composition of the soil bacterial community was determined by high-throughput 16S rRNA gene amplicon sequencing. The results showed that the soil water content, nutrients and bacterial communities were more similar to natural wetlands under the process of natural restoration. Proteobacteria, Acidobacteria, and Chloroflexi were the dominant phyla in all samples. Bacterial diversity declined during natural restoration, while the relative abundance of bacteria changed significantly in the process of natural restoration, which indicated that the structure and composition of bacterial community may be a good indicator of wetland health or restoration status. Meanwhile, the soil environment changed from oligotrophic to eutrophic with the accumulation of soil nutrients and some bacterial assemblages appeared synchronously, suggesting the dependence of those bacteria on nutrients and the indication of natural restoration in wetlands.