The Characteristics of Soil Microbial Community Structure, Soil Microbial Respiration and their Influencing Factors of Three Vegetation Types in Alpine Wetland Ecosystem

Soil microorganisms are essential members of the wetland ecosystem, and they participate in the cycling of various materials in the ecosystem. The heterotrophic respiration of soil microorganisms is an important way to release carbon dioxide (CO₂) from the soil carbon pool to the atmosphere, and it is influenced by a variety of factors. Here, we collected soil samples from different vegetation types in alpine wetland ecosystems to study the relationships among soil microbial respiration (SMR), microbial community composition and soil physicochemical properties. The results showed that: (1) Soil microbial species were abundant in the study area, with a high percentage of Gp1, Gp2 of the Acidobacteria and Spartobacteria_genera_incertae_sedis of Verrucomicrobia. Tussock Marsh had the richest bacterial taxa. Soil organic carbon (SOC), total nitrogen (TN), moisture content (MC), carbon-nitrogen ratio (C/N) and bulk density (BD) were important influencing factors on the soil bacterial community structure and diversity. (2) Among the six functional pathways predicted, Metabolism was the most active function in microbial taxa and played an important role in the distribution of bacteria. (3) The SMR varied widely among the three vegetation types and the soil microbial respiration intensity of the Larch Island Forest Wetland was greater. The Abundance-based Coverage Estimator (ACE) index of microorganisms was significantly negatively correlated with SMR (p < 0.05), while all other microbial diversity indices were not significantly correlated with it. Transcription, Metabolism of Cofactors and Vitamins and Carbohydrate Metabolism were also important factors influencing SMR.