Abstract: The Lhasa River Basin is known for its richness in agricultural resources, which are facing the most significant environmental pressure in Tibet. Changes in the structure and composition of soil microbial communities in the region can provide insights into soil ecology and environmental vulnerability under the influence of climate change and human activities. We analyzed soil microbial community structure and the environmental influencing factors in five ecosystems, including natural shrubland, sparse shrubland, artificial shrubland, artificial forest, and natural grassland, using high-throughput sequencing method. The results showed that: (1) Soil bacterial diversity and fungal diversity were highest in the artificial shrubland. (2) Soil bacteria in all the five ecosystems were dominated by Proteobacteria, Actinobacteriota, and Acidobacteriota, while fungi were dominated by Ascomycetes, Basidiomycota, Chytridiomycota, and Calcarisporiellomycota. (3) In the shallow layer, soil bacterial community clusters were similar in natural grassland and artificial forest. In the deep layer, soil bacterial community clusters were similar in natural shrubland, sparse shrubland, and artificial shrubland. Except for natural shrubland, fungal communities in all the ecosystems exhibited a trend of separation in both shallow and deep layers. (4) The structure of bacterial communities was significantly influenced by soil water content, electrical conductivity and available potassium, while the structure of fungal communities was mainly affected by soil water content, total nitrogen, available phosphorus and available potassium. These findings characterized the soil microbial community structure of different ecosystem types in the Lhasa River Basin.

Key words: Lhasa River Basin, ecosystem type, microbial community characteristics, high-throughput sequencing, environmental factor