Land-use change alters the bacterial community structure, but not forest management.

Deforestation has a large impact on soil fertility, especially on steep slopes, but by applying sustainable management practices, local communities in Oaxaca (Mexico) have tried to avoid the most negative effects on the forest ecosystems they manage. In this study, the characteristics and bacterial community structure were investigated from soil sampled in triplicate (n = 3) with different land use, i.e., arable, natural forest, sustainable managed, and reforested soil. The pH was significantly higher in the arable (6.2) than in the forest soils (≤ 5.3), while the organic matter was > 2 times higher in the natural forest (80.4 g/kg) and sustainable managed soil (86.3 g/kg) than in the arable (36.8 g/kg) and cleared and reforested soil (39.3 g/kg). The higher organic matter content in the first two soils was due to leaf litter, absent in the other soils. The species richness (q = 0), the typical (q = 1) and dominant bacteria (q = 2) were not affected significantly by land use. The beta diversity, however, showed a significant effect of land use on species richness (p = 0.0029). Proteobacteria (40.135%) and Actinobacteria (20.15%) were the dominant bacterial phyla, and Halomonas (14.50%) and the Verrucomicrobia DA101 (3.39%) were the dominant genera. The bacterial communities were highly significantly different in soil with different land use considering the taxonomic level of genus and OTUs (p ≤ 0.003). It was found that the sustainable managed forest provided the local community with sellable wood while maintaining the soil organic matter content, i.e., sequestered C and without altering the bacterial community structure.