Abstract:

This study aimed to investigate changes characteristics of soil microbial communities under typical vegetation in plateau forest ecosystems; a case study was undertaken the Beichuan River source area National Nature Reserve of Datong, Qinghai. This study analyzed 0-20 cm soil samples from six different vegetation species (Betula platyphylla, Populus cathayana, Picea crassifolia, Larix gmelinii var. principis-rupprechtii, Dasiphora fruticosa, and alpine meadow). The composition and diversity of soil microbial communities were determined using Illumina NovaSeq sequencing, and soil physicochemical properties were measured via chemical analyses. The study investigated the correlation between soil microbial communities and soil physical and chemical properties as well as identified factors driving the changes in soil microbial communities. The results revealed the presence of 39 phyla, 785 genera, and 1651 species of bacteria and 17 phyla, 439 genera, and 559 species of fungi in the six vegetation samples. The total number of common microorganisms was lower than the specific one. The six vegetation soils were dominated by Proteobacteria, Actinobacteriota, and Acidobacteriota as well as by Basidiomycota and Ascomycota fungal phyla. The bacterial communities of the six vegetation species exhibited significant differences in alpha diversity, with the highest diversity observed in the Populus cathayana Rehder bacterial community. Conversely, the fungal communities showed similarities, with the Betula platyphylla fungal community exhibiting the highest alpha diversity. The correlation between soil microbial communities and soil physicochemical properties was analyzed. At the bacterial phylum level, a significant negative correlation was found between soil pH and Desulfobacterota (P<0.05). Additionally, soil organic matter and total nitrogen contents were found to be highly significantly positively correlated with Ascomycota (P<0.01). At the fungal phylum level, a significant negative correlation was observed between soil pH and Entorrhizomycota (P<0.05). Soil organic matter and total nitrogen contents were highly significantly positively correlated with Zoopagomycota (P<0.01) and significantly negatively correlated with Glomeromycota (P<0.05). Soil pH is a key environmental factor that affects the changes in soil bacterial and fungal communities.

Key words: microbial community, microbial diversity, vegetation type, Qinghai alpine region