Effects of close-to-nature management of plantation on the structure and ecological functions of soil microorganisms with different habitat specialization.

Aims: We investigated the changes in structure and driving factors of soil microbial communities with different habitat specialization and their effects on soil nitrogen mineralization during close-to-nature of plantation. Methods: Close-to-nature forests were classified into Pinus tabulaeformis forest stage, mixed forest stage and near natural forest stage based on the coverage ratio of P. tabulaeformis to tree layer, and natural secondary forests selected for control. Soil physicochemical properties, enzyme activities, and nitrogen mineralization processes were determined. Soil microbial community structures were analyzed using high-throughput sequencing. Soil microorganisms were classified into habitat-generalized, neutral and specialized groups according to the relationship between the actual niche width and the confidence interval of simulated zero distribution. Results: (1) The extreme value of soil properties mainly appeared in the mixed forest stage. (2) The frequency of fungi and bacteria of each group both increased during near-naturalization with the generalized group increased fastest. (3) The bacterial β-diversity of each group differed significantly while the fungi not. (4) The soil bacterial structure of each group was affected by distance and soil properties. The influence of the former increased while the latter decreased with habitat specialization. (5) The structure of dominant genera of each group in the natural secondary forests significantly differed from close-to-nature forests and their structure well explained the soil nitrogen mineralization processes. Conclusion: Close-to-nature has improved soil properties, microbial community structure and nitrogen mineralization rate. Each habitat specialization group of microbial responded differently to near-naturalization and their structure well explained soil nitrogen mineralization processes. [ABSTRACT FROM AUTHOR]