The composition of tree species might influence microbial diversity considerably,yet investigation of the consequences of changes in diversity for stability of themicrobial community is still in its early stages. Understanding how diversity gov erns community stability is vital for predicting the response of an ecosystem toenvironmental changes. Phylogenetic diversity (PD) describes the distinct evolu tion of species in a community, and might be useful for estimating the effects ofbiodiversity on ecosystem function and stability. High-throughput 16S rRNA genesequencing was used to examine soil bacterial phylogenetic distances, phylogeneticdiversity and interactions between individuals in five single-species plantations andthree mixed-species plantations. The plantations were established on the same ini tial substrate, and sampling was at 68 relatively spatially independent sites. Ourresults showed that mixed tree species enhanced soil bacterial phylogenetic diver sity and community stability, and that phylogenetic diversity had a positive effecton stability of the soil microbial community. We also found evidence that micro bial communities characterized by distantly related species with weak interactionswere more stable in mixed plantations than communities with strong interactions insingle-species plantations. These results may be explained by the “insurancehypothesis”, that large phylogenetic diversity of microbial communities, whichshare different ecological niches, insures them against decline in their stability.This is because, even if some microbial species fail to deal with environmentalchange, others might not necessarily be affected similarly. Our findings demon strate that phylogenetic diversity is the main controlling factor of the variation instability across sites and requires more attention in sustainable forest management.
Highlights
• Mixed species considerably improved stability of the soil bacterial community.
• Bacterial phylogenetic diversity was greater in mixed- than in single-speciesplantations.
• Mixed species resulted in weak microbial interactions in a community.
• There was a strong relation between phylogenetic diversity and stability.
