Change in Soil Microbial Community Compositions and Diversity Following the Conversion of Tropical Forest to Rubber Plantations in Xishuangbanan, Southwest China

Abstract

The ecological consequences of converting tropical forests to rubber plantations on the soil microbial compositions and diversity remain unknown. By using an Illumina MiSeq sequencing analysis, we assessed the compositions and diversity of bacterial and fungal community in soils of rubber plantation (or rubber forest, RF), secondary tropical forest (STF), and tropical seasonal rainforest (TSR) in Xishuangbanna, southwest China. Our findings revealed that (a) for bacterial composition, Bacillaceae was the most dominant family (13.60%) in RF soil, while it only accounted for 4.13% in STF and 6.92% in TSR. For fungal composition, the largest family in soils of RF was Basidiomycota_unclassified. However, the largest family in STF and TSR was Russulaceae. (b) Number of operational taxonomic units, Chao index, and Shannon index of bacterial community in soil of RF were significantly higher than those of TSR and STF. However, these diversity indices of fungal community in RF were significantly lower than those of TSR and STF. (c) Soil pH and total phosphorus were very important drivers for bacterial community, whereas soil organic matter and total nitrogen were the most important factors for fungal community. (d) The microbial biomass carbon in RF was relative lower than those in STF and TSR, which suggested that the total microbial biomass decreased after forest conversion. To protect the total diversity of this region, the individual farmers should use herbicides as little as possible to reserve ground vegetation. And the government could outline a land-use policy that prohibits the cultivation in areas of natural vegetation.