Revegetation by sowing reduces soil bacterial and fungal diversity

Aim The aim of this study was to understand the effects of revegetation on the diversity of bacteria and fungi in soil by sowing a single species and exploring the underlying mechanism. Location Beijing, China. Taxon Plants and Microbes. Methods In a short‐term ecological restoration experiment, one natural recovery treatment and three seed sowing treatments were chosen to assess their effects on the alteration of fungal and bacterial diversity. Plant species richness, abundance, and height were investigated. The diversity of fungi and bacteria was analyzed by high‐throughput sequencing technologies. Linear mixed‐effects model analysis was used to examine the effects of different restoration methods on biodiversity and ecosystem functions. Pearson's correlation analysis, analysis of covariance, and structural equation modeling (SEM) were used to examine the relationship between biodiversity and environmental factors. Results Species richness and the Shannon–Wiener Index (H′) of plants in the sown treatments were lower than in the natural recovery treatment, especially with sowing of Medicago sativa L. Similarly, the sum of the observed species and H′ of fungi and bacteria significantly decreased in the sown treatments. Moreover, plant density, community coverage, and soil moisture increased markedly, while soil bulk density decreased in the sown treatments. Importantly, SEM showed that sown treatments reduced the diversity of plants through increasing plant density, while it decreased the diversity of fungi and bacteria through decreasing the plant diversity and increasing soil moisture. Main conclusions Our findings confirm that ecological restoration by sowing could improve soil conditions, but may be unfavorable to the amelioration of soil microbial diversity in the short‐term. Restoration practitioners should consider long‐term studies on the dynamics of biodiversity in the above‐ and belowground after revegetation by native species to achieve goals related to biodiversity conservation. Our study has clearly addressed how and by what mechanism different ecological restoration methods influence the diversity of fungi and bacteria in the soil. We found that restoration by revegetating reduced the diversity of plants through increasing plant density, and decreased the diversity of fungi and bacteria through decreasing the plant diversity and increasing soil moisture.