Effects of close-to-nature management of Plantation on the structure and ecological functions of different habitat specificity taxa of soil microorganisms
Authors: Qiu Zhenlu , Shi Cong , Zhang Mei , Shi Fuchen 
Published: April 2022

Abstract
Aims: To investigate the changes in community structure with different habit specificity of soil microbial and the differences of effects on soil nitrogen mineralization during the near-naturalization process, as well as to evaluate the effects of planted forest on close-to-nature operations.Methods: Forest with 65-years succession sequence of near-naturalization was used as research plots in the Baxianshan National Nature Reserve at the eastern foot of Yanshan Mountain in the warm temperate zone in northern China. Three typical stages of near-naturalization, namely, pure Pinus tabulaeformis forest, mixed forest and near-natural forest, were set up with natural secondary forest without naturalization as a control. We also classified soil microorganisms into three groups according to the degree of habitat specificity: generalized, neutral and specialized. Soil physicochemical properties, enzyme activities, and rates of nitrogen mineralization processes were measured, and soil fungal and bacterial community structures were analyzed using high-throughput sequencing.Results: (1) total carbon, organic carbon, total nitrogen, nitrate nitrogen and ammonia nitrogen contents were higher in natural secondary forests than those in near-naturalized stands, while pH, effective phosphorus, total phosphorus and dry matter contents were the highest in the near-natural forest stage. Acid phosphatase and cellulase activities of natural secondary forest soils were significantly higher than that of near-naturalized stands, but dehydrogenase and β-glucosidase activities and the rate of nitrogen mineralization-related processes were the lowest in natural secondary forests, (2) Under the same habitat specificity, the fungal niche width was larger than the bacterial niche width, and increased with the increase of the degree of approaching naturalization, but was significantly smaller than that of natural secondary forests. (3) The effect of near-naturalization on the spatial richness of microbial communities decreased with degree of habitat specificity and showed a temporal decay (the difference in community structure was greater in the early stages than in the later stages). (4) The explanation of community structure by soil physicochemical and enzymatic activities decreased with habitat specificity, pH was the dominant factor affecting the structure of fungal generalized and neutral taxa, urease activity mainly affects fungal specialized taxa, and the distribution of bacterial communities was mainly influenced by the chemical characteristics of soil carbon, nitrogen and phosphorus, (5) The structure of the dominant genera of each habit-specific group in the natural secondary forest was significantly different from that of the near-naturalized forest, and the abundance distribution of the dominant genera well explained the differences in soil nitrogen mineralization processes. Conclusion: Generalist taxa of soil microbial were more pronounced to close-to nature development of planted forest. Close-to-nature operations have resulted in positive improvements in both soil nutrients and microbial community structure, but still differed significantly from those in natural forests.