Correlations between dominant vegetation type and composition and diversity of soil bacterial communities in a subtropical forest

Single and mixed vegetation types have significant effects on soil
parameters and the composition and diversity of soil bacterial
communities. To understand the influence of different vegetation types on
the structure of soil bacterial community across soil depth in a
subtropical forest, we assessed the relative abundance of edaphic
bacterial community and soil parameters, including pH, cation exchange
capacity (CEC), and dissolved organic carbon (DOC) in Daiyun Mountain
Nature Reserve in Fujian Province, southeastern China. The study area
constitutes pine coniferous forest (CF) of pinus taiwanensis, broad-leaved
forest (BF) of castanopsis fabri, and a mixed forest comprising CF and BF
(MF). Quantitative PCR and Illumina sequencing of 16S rDNA were used to
analyze the abundance, diversity, and composition of soil bacteria. The
results showed that the pH, CEC and diversity of tree species are all
associated with the composition of the bacterial community in the soil. It
was found that CEC, soluble organic nitrogen (DON) and pH largely affected
the structure of soil bacterial community in A horizon, whereas CEC,
moisture content (MC) and organic phosphorus (OP) affected the structure
of soil bacterial community in B horizon. We found that the dominant taxa
in the CF and BF were Proteobacteria and Acidobacteria, respectively. The
results of both mental and random forest (RF) analyses displayed groups
according to vegetation types, indicating that the bacterial communities
in the research site were significantly influenced by vegetation types in
subtropical forests. The study highlights the ecological effects of forest
management and elucidates the differences in the functional structure of
soil bacterial communities under different vegetation types and soil
depths.