Soil Bacterial Characteristics Under Four Habitats with Different Vegetation Communities on the Qinghai-Tibetan Plateau

Soil bacteria play important roles in regulating biogeochemical cycles and maintaining ecosystem function. However, our knowledge of patterns and driving factors of permafrost microbial communities under typical alpine meadow habitats with different vegetation communities is limited. We analyzed the relationship between soil bacterial community and changes of environmental factors among four habitats (swamp wetland, swamp meadow, meadow, and mature meadow) with different dominant vegetation types on the eastern edge of Qinghai-Tibetan, China. The results showed that though the bacterial community composition among four habitats was similar, the proportions of dominant species and the bacterial biomarkers in each habitat were unique. The bacterial community structure of mature meadow was obviously distinct from the other three habitats, which derived from the significant difference in soil nutrients and shoot biomass compared to the others. Specifically, distance-based redundancy analysis showed that soil total nitrogen and soil water content explained the greatest difference in bacterial structures, followed by soil temperature, pH and shoot biomass. Different habitats formed various network patterns, which showed more significant connections in swamp meadow and meadow than swamp wetland and mature meadow. Rhizomicrobium, Pseudonocardia, Geobacter, Bryobacter, Syntrophorhabdus, Nitrospira, Solirubrobacter and Pedomicrobium were the most important keystone genera in the bacterial co-occurrence networks.