Higher Variability in Diversity and Functionality of Soil Fungal Communities Compared to Bacterial Communities in Alpine Treeline Ecotone.

Although patterns of microbial diversity in forest ecotones have been well-studied, the association between microbial diversity and function in treeline zone remain largely unexplored. This study examined the soil microbial diversity and community structure along altitudinal gradient (High, Medium, Low) and at different soil depths (10 cm, 20 cm and 30 cm) of the Abies georgei var. smithii forest in a typical ecotone area of treeline on Sygera Mountains in southeastern Tibet. Results indicated that the alpha diversity of bacterial communities is highest in the medium elevation, while fungal diversity is lowest. Additionally, both bacterial and fungal diversity decrease with increasing soil depth. Bacterial community structure is significantly influenced by both elevation and depth. Fungal community structure is primarily affected by the elevation. Network analysis revealed that microbial functionality is more closely related to these communities than microbial biodiversity in-dices. In the treeline zone, the functional differences among fungi across various elevations and soil depths are significantly greater compared to those of bacteria.