Soil microbiome, organic matter content and microbial abundance in forest and forest-derived land cover in Cat Tien National Park (Vietnam)

Loss of tropical forests leads both to the loss of aboveground biodiversity and to the changes in belowground biological activity. Planted secondary forests return canopy cover, but the reversibility of belowground changes may depend on soil properties, forest age and tree species composition. We studied microbial communities in an array of soils in southern Vietnam under different vegetation: natural tropical forests, grasslands on deforested area and 20 and 30 years-old forest plantations. Conversion of natural forests into grasslands led to the loss of half of soil organic matter and microbial abundance, soil moisture decreased, bacterial community structure changed and beta-diversity increased. Bacterial alpha-diversity and pH were not affected by deforestation. Reforestation for 30 years restored bacterial and archaeal abundance, partially restored bacterial community structure, but did not restore fungal abundance and organic matter content. Thus, forest planting in southern Vietnam restores soil microbiome properties partially, but the complete restoration apparently requires much more than 30 years of secondary forest succession. [Display omitted] •Deforestation in Southern Vietnam changes soil bacterial community structure.•Deforestation decreases soil moisture, organic matter content and microbial abundance.•Reforestation for 30 years restores soil bacterial community structure and abundance.•Reforestation does not restore soil moisture, organic matter content and fungal abundance.