Effect of Alteration in Precipitation Amount on Soil Microbial Community in a Semi-Arid Grassland

Climate models predict significant changes in precipitation magnitude in semi-arid grasslands, so it is vital to improve our understanding of how changing precipitation affects microbial communities in grassland ecosystems. Using a long-term field manipulation experiment, we evaluated the responses of microbial communities to a decrease (DP) and an increase (IP) in precipitation on a semi-arid grassland in northern China. The results showed that bacterial species richness decreased significantly with DP but remained stable under IP. Relative abundance of oligotrophic, slow-growing bacterial phyla (e.g., Chloroflexi and Acidobacteria) increased with DP but decreased with IP, whereas the relative abundance of copiotrophic, fast-growing bacterial phyla (e.g., Proteobacteria and Bacteroidetes) decreased with DP but increased with IP. In contrast, diversity, species composition, and relative abundance of different fungal phyla change little with DP or IP. These results indicate a greater sensitivity of bacteria to precipitation changes than fungi, and the sensitivity of bacteria to DP was higher than IP. Our findings are important for understanding soil microbial dynamics under future climate change scenarios.

Automated summary

In semi-arid grasslands, changes in precipitation have a greater impact on bacterial communities than fungal communities, and bacterial communities are more sensitive to a decrease in precipitation. A long-term field manipulation experiment in northern China showed that bacterial species richness significantly decreased with decreased precipitation but remained stable with increased precipitation. The relative abundance of oligotrophic, slow-growing bacterial phyla increased with decreased precipitation but decreased with increased precipitation, while the relative abundance of copiotrophic, fast-growing bacterial phyla decreased with decreased precipitation but increased with increased precipitation. In contrast, diversity, species composition, and relative abundance of different fungal phyla showed little change with precipitation changes.