Recent History of Land Use Buffers the Shifts of Soil Bacterial Community

The interaction among plants, soil and microorganisms is considered to be the major driver of the ecosystem functions and any modification on plant cover and/or soil properties might affect the microbial structure, which, in turn, will influence the ecological processes. Assuming that soil properties are the major drivers of soil bacterial diversity and structure, within the same soil type, can the plant cover cause significant shifts on soil bacterial community composition? To address this question we used 16S rRNA pyrosequencing to detect differences in diversity, composition and/or relative abundance of bacterial taxa from an area covered by pristine forest and eight years old grassland surrounded by this forest. After removing the natural forest, the soil bacterial community did not suffer a great differentiation. Sixty nine percent of the operational taxonomic unities (OTUs) were shared between environments. Overall, forest samples and grassland samples presented the same diversity and the clustering analysis did not show the occurrence of very distinctive bacterial communities between environments. However, we detected eleven OTUs in statistically significantly higher abundance in the forest samples but in lower abundance in the grassland samples and twelve OTUs in statistically significantly higher abundance in the grassland samples but in lower abundance in the forest samples. Those results illustrate that as long as the soil chemical and physical conditions do not suffer great alterations, the recent history of land use buffers the shifts of soil bacterial community.