Variations in soil microbial communities in the sedge-dominated peatlands along an altitude gradient on the northern slope of Changbai Mountain, China

The mechanisms that shape soil microbes in peatlands along the altitude gradient remain unresolved due to limited data and inconsistent findings along different vertical vegetation belts from investigations. In this study, we present results of soil phospholipid fatty acids (PLFAs) profiles from an altitude gradient survey (300-1500 m) in Changbai Mountain aimed at determining the elevational patterns of soil microbial communities and their driving forces in the sedge-dominated peatlands. The results showed that the total microbial lipid biomass in the sedge-dominated peatlands increased with altitude. However, there were no obvious trends with altitude in ratios of the fungi to bacteria (F/B), the Gram positive bacteria to Gram negative bacteria (G+/G-), and the bacteria to actinomycetes (B/ACT). Redundancy analysis indicated that the dissolved organic carbon (DOC) explained most variation in soil microbial groups, while mean annual temperature (MAT) explained most variation in microbial community structure. Variation partitioning analysis revealed that climatic factors had greater influences on soil microbial community structure than soil physical and chemical properties, and 53% of the total variance was explained by MAT, mean annual precipitation (MAP) and their combined effects. This finding challenges the prevailing view that local soil properties, but not climate, control soil microbial community structure along the altitude gradient, and enhances our understanding of the role of soil microbes as carbon pumps in sedge-dominated peatlands in the process of global warming.