**5. Conclusions**

The diversity and composition of soil microbial communities varied greatly with forest succession. We summarized the following points:


To sum up, forest communities at different successional stages not only share dominant soil bacterial and fungal taxa but also support significantly different dominant groups of soil bacteria and fungi with community succession. The results imply that maintaining different succession stages of forest communities through moderate disturbances is beneficial to the conservation of soil biodiversity at the forest region level.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/f13020289/s1, Table S1: Site characteristics across a successional gradient in the subalpine forest on eastern Qinghai-Tibet Plateau; Table S2: Discrepancy of relative abundance of the dominant phyla of soil bacterial and fungal community composition among different forest succession stages; Table S3: The analysis of similarities (ANOSIM) among different forest succession stages based on the distance algorithm of Bray–Curtis; Table S4: The detrended correspondence analysis (DCA) based on based on the OTUs data at 97% sequence identity; Table S5: The detection of collinearity of forest variables by the analysis of Variance Inflation Factor (VIF).

**Author Contributions:** W.Y.: Conceptualization, funding acquisition, project administration, resources, supervision, validation and writing—review and editing. Z.W.: conceptualization, data curation, investigation, methodology and writing—original draft. F.L.: funding acquisition and investigation. Z.W., Y.B., J.H., F.L., X.L., Y.D. and Y.J.: investigation. Z.W., R.C. and H.W.: methodology. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the National Natural Science Foundation of China (grant numbers 32071554, 32001139).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** All data generated or analyzed during this study are included in this published article. Data in Table 6 is available through Zhang et al. 2016, Chai et al. 2019, Zhao et al. 2020, Li et al. 2020, Liu et al. 2020 (25), Liu et al. 2020 (62), Shang et al., 2021, Wang et al. 2021.

**Acknowledgments:** The authors of this study appreciate the field assistance of Wanglang National Nature Reserve involved in the initial sampling assignments.

**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
