3.3 | Distribution of bacteria in soil samples
At the phylum level, Proteobacteria, Chloroflexi, Acidobacteria, and
Actinobacteria were the dominant bacteria in all the samples, accounting
for 88.23% of the total sequence data. Other abundant phyla were GAL15,
WPS-2, Verrucomicrobia, Bacteroidetes, Gemmatimonadetes, and
Planctomycetes (Figure 3a). The phyla with comparatively high relative
abundance, namely, Chloroflexi, Acidobacteria, Actinobacteria, and
WPS-2, were all significantly lower at the 40–60 cm soil depth than for
the other depths, except for Proteobacteria (Figure 3b). At different
slope positions, the relative abundance of Proteobacteria was the lowest
at the top of the slope, while that of Acidobacteria was the highest.
The relative abundance of Actinobacteria was lowest at the midslope
(Figure 3c). In the different forest types, the abundance of
Proteobacteria was the highest in LF. The abundance of Chloroflexi and
Acidobacteria were highest in NA and lowest in LF, while the abundance
of Actinobacteria was highest at LF and lowest in GNA. There were no
significant differences in the abundance of Chloroflexi between the
forest types (Figure 3d).
Plantation altered the relative abundance of the dominant phyla (Figure
4) in different forest types, with Acidobacteria, WPS-2, and
Rokubacteria showing highly significant differences(p< 0.01.Significant differences in the abundance of
Actinobacteria, unclassified_k_norank_d_Bacteria, and
Gemmatimonadetes were recorded, while the relative abundance of
Proteobacteria did not differ significantly. There were no significant
differences in the bacterial communities at different depths or slopes.