Effect of increasing precipitation and warming on microbial community in Tibetan alpine steppe

Abstract Soil microorganisms play an important role in regulating the feedback of Alpine steppe ecosystems to future climate change. However, the interaction effect of warming and increasing precipitation on soil microorganisms remains unclear, in the face of an ongoing warmer and wetter climate on the Tibetan Plateau. In this study, we investigate the multi-factorial effects on soil microbial diversity, community structure, and microbial interactions in a three-year climate change experiment established in an Alpine steppe on the Tibetan Plateau, involving warming (+2 °C), +15% increasing precipitation and +30% increasing precipitation. Compared to warming, warming plus increasing precipitation alleviated the decrease in microbial diversity, and increased the dissimilarities in microbial community structures, largely influenced by water and substrate availability. We further observed differences in moisture increased the differences in microbial diversity and dissimilarities in microbial community structures across different precipitation levels under ambient temperature. Interestingly, warming plus increasing precipitation could create more ecological niches for microbial species to coexist but may lessen the strength of microbial interactions in contrast to increasing precipitation alone. Collectively, our findings indicate that microbial responses to future climate change in Alpine steppe soils will be more complex than those under single-climate-factor conditions.