the responses of MOBs diversity and community structure to elevation-induced environmental changes in Gongga Mountain.

The aerobic methane oxidizing driven by methane oxidizing bacteria (MOBs) in forest topsoil plays a critical role in carbon cycling and global warming alleviation. Here, we surveyed the responses of MOBs diversity and community structure to elevation-induced environmental changes in Gongga Mountain (from 1800 m to 4100 m). Along the continuous elevational gradient, a “hump-backed” a-diversity pattern was observed, while community structure showed distinctive differentiation, especially between low (1800 m to 2800 m) and high elevations (3000 m to 4100 m). The conductivity, soil temperature and precipitation showed relatively high explaining abilities for such variation. This implied that these three environmental traits could be good indicators for the variations of MOBs diversity and community structure along the elevational gradient of Gongga Mountain. Using null model and variation partitioning analyses, a higher correlation between MOBs community structure and environmental changes was observed in low elevations than those in high elevations, suggesting that environmental filtering likely resulted in the distinctive community differentiation between low and high elevations. This study highlighted the importance of deterministic factors in regulating the diversity pattern and community assembly of MOBs in mountain ecosystems.