Soil methanotrophic community structure and diversity in different vegetation types at elevation gradient of Gongga Mountain, Southwest China

Abstract

Methane (CH4) is the second abundant greenhouse gas. Aerobic methane oxidations of topsoil in forest are identified as an important sink of atmosphere methane, playing critical roles in carbon cycle and global warming alleviation. Comparing the community structure and diversity of methane oxidizing bacteria (MOBs) in different vegetation ecosystems could provide new insights into the relationships between vegetation types and community of MOBs. In this study, we collected 92 soil samples from four types of vegetation along the elevation gradient of Gongga Mountain, and further assessed the community structure, diversity and potential drivers of MOBs across the four vegetation types using Miseq sequencing and bioinformatics methods. The result indicated that MOBs community compositions in evergreen and deciduous broad-leaved forest (EDBF) and coniferous and broad-leaved mixed forest (CBMF) was more similar, whereas in dark coniferous forest (DCF) and shrub meadow area (SMA) soils, MOB composition was more similar. In the four types of vegetation, α-diversities of MOBs in EDBF and CBMF were significantly higher than that in the other three vegetation types (P＜0.001), whereas β-diversities in soils of DCF and SMA were significantly higher than those in EDBF and CBMF (P＜0.001). Spearman analysis indicated that the relative abundance of different MOBs in four types of vegetation showed different responses to environmental change. Factors including soil total nitrogen, conductivity and soil temperature appeared to govern the variation of α-diversity across the four vegetation types. Partial Mantel test and redundancy ana-lysis (RDA) suggested that environmental parameters likely contributed more to diversity variations in soils from EDBF and CBMF, whereas diversity variations in soils from DCF and SAM might be driven by other potential environmental factors or mechanism. Precipitation appeared to drive the β-diversity variation between vegetation of EDBF and CBMF and vegetation of DCF and SAM. Our study suggested that the community structure and diversity variation of MOBs in different vegetation types might be governed by both soil properties and climate change.