The soil microbial community structure under retrogressive succession of an alpine wetland in the arid area

Abstract:

[Objective] To explore the effects of retrogressive succession of the alpine wetland of Bayanbulak Swan Lake in Xinjiang on soil properties and microbial community structure by relying on the typical transect of retrogressive succession (swamp-swamped meadow-meadow). [Methods] The soil microbial community structure was analyzed by high-throughput sequencing. [Results] The retrogressive succession of the alpine wetland changed the species composition of soil microorganisms at the operational taxonomic unit (OTU) level. The ACE, Chao1, Simpson, and Shannon diversity indexes of soil microorganisms in the meadow area were lower than those in the swamp area and the swamped meadow area (P<0.05). With the occurrence of succession, the relative abundance of Proteobacteria, Acidobacteria, Bacteroidetes, and Ascomycota decreased, while that of Actinobacteria, Gemmatimonadetes, Basidiomycota, and Mortierellomycota increased. Principal coordinates analysis showed that soil microbial communities presented different degrees of dispersion at each stage of retrogressive succession. The species dispersion in the meadow area was larger than that in the swamped meadow and swamp areas where a certain degree of aggregation appeared. Further, the redundancy analysis indicated that soil organic carbon, soil water content, soil bulk density, microbial biomass nitrogen, and microbial biomass carbon were the key factors affecting the dominant microbial phyla and genera. [Conclusion] The retrogressive succession of the alpine wetland decreased the soil microbial community diversity and led to the transition from eutrophic to oligotrophic community.