Diversity and Community Structure of Soil Bacteria of Different Vegetation Types in Volcanic Lava of Wudalianchi, China

Volcanic lava has a complete primary succession; the plant community composition can explain a great part of the variation of soil microbial diversity and community structure. Bacteria dominate the soil microbial communities in abundance and diversity, and they are important drivers of organic matter decomposition and nutrient cycling. With 16S rRNA Illumina Miseq sequencing techniques, we analyzed the soil bacterial communities and diversities associated with different vegetation types in Wudalianchi. Shrub soils had the highest pH, MC, TOC, TN, AP, AN and NN, whereas moss soils had the lowest. The Shannon, Ace, and Pd indices of bacteria showed significant differences in the different vegetation types (p < 0.05). Bacterial Ace, Shannon, and Simpson indices peaked in Herb and Shrub is highest. The Proteobacteria, Actinobacteriota, Acidobacteriota, Planctomycetota and Chloroflexota were the most abundant groups at phyla level. Bacterial community composition varied significantly across vegetation types (p < 0.05). At the family level, Pseudonocardiaceae predominated in moss soils. Redundancy analysis and correlation analysis revealed MC, pH, and TP as key environmental factors shaping bacterial communities. Functional predictions based on taxonomic data indicated that chemoheterotrophy and aerobic chemoheterotrophy were the predominant functional groups. In conclusion, although soil microbial composition and diversity differed markedly across vegetation types following volcanic eruptions, functional groups prioritized carbon fixation strategies.