Soil carbon, nitrogen, and phosphorus cycling microbial populations and their resistance to global change depend on soil C:N:P stoichiometry

Maintaining stability of ecosystem functions to global change calls for a better understanding regulatory factors of functionally specialized microbial-groups and their population-response to disturbance. Here, we explored this issue by collecting soils from 54 managed ecosystems in China and conducting a microcosm experiment. Soil carbon:nitrogen:phosphorus (C:N:P) stoichiometry imparted a greater effect on the abundance of microbial-groups associated with main C, N and P biogeochemical processes in comparison with the mean annual temperature and precipitation. Nitrogen cycling genes, including bacterial amoA-b, nirS, narG and norB, exhibited the highest genetic resistance to N deposition. The amoA-a and nosZ genes exhibited the highest resistance to warming and drying-wetting cycles, respectively. Soil total C, N and P contents, and their ratios had a strong direct effect on the genetic resistance of microbial-groups, which was dependent on the mean annual temperature and precipitation. Specifically, soil C:P ratio exerted the main predictor and drivers of N cycling genetic resistance to N deposition. Soil total C and N contents, and their ratios were the main predictors of P cycling genetic resistance to the three aforementioned disturbances. Overall, our work highlights the importance of soil stoichiometric balance for maintaining the ability of ecosystem functions to withstand global change.