Effects of long-term warming on soil prokaryotic communities in shrub and alpine meadows on the eastern edge of the Qinghai-Tibetan Plateau

Abstract

The variations in response of the soil prokaryote community structure to long-term climate warming among different vegetation types in alpine areas are not fully understood. After an 18-year warming experiment, changes in the diversity and structure of soil prokaryote communities in alpine and shrub meadows of the Tibetan Plateau were analyzed based on 16S rDNA MiSeq sequencing. Proteobacteria (26.70 %), Actinobacteria (20.90 %), and Acidobacteria (13.09 %) were the dominant soil bacterial communities; however, Crenarchaeota (5.69 %) was the dominant archaea at the phylum level. Warming did not significantly affect the top 11 prokaryotic communities in the shrub meadow soil. In meadow soils, however, we found an increase in the relative abundances of Crenarchaeota, Acidobacteria, Chloroflexi, and Planctomycetes and a decrease in the relative abundances of Actinobacteria and Proteobacteria. In terms of alpha-diversity, warming significantly increased the Chao1 and the observed species indices in both the meadow and shrub meadow soils. The soil prokaryote community in the meadow soil was more sensitive to simulated warming than that in the shrub meadow soil. The soil pH and water content were the primary factors that influenced variation in the overall structure and diversity of the soil prokaryotic community. Therefore, the response of soil prokaryote composition and structure (at the phylum level) to long-term warming largely depended on vegetation type, but the response of alpha-diversity was similar among different vegetation types. We conclude that the vegetation type plays a regulatory role in the sensitivity of alpine soil microbial communities to warming.