Impact of drought on terrestrial ecosystem C-N-P stoichiometry and microbial nutrient limitation

Carbon (C), nitrogen (N), and phosphorus (P) stoichiometric traits are of critical importance to ecosystem functioning. Exploring the effects of drought on the C-N-P stoichiometric is of great significance for understanding element cycling and nutrient limitation in terrestrial ecosystems; however, it has not been uniformly and reliably concluded on a global scale. Here, based on 505 paired observational statistics, we systematically analyzed the effect of drought on terrestrial ecosystem C-N-P stoichiometry on the global scale. Drought greatly decreased the C:N ratio in soil (9.9%), enzymes (13.9%), shoots (7.9%), and roots (8.1%). Furthermore, soil microbes were limited by N, whereas plants were restricted by P under drought stress. Drought intensity and duration were significantly negatively correlated with shoot N:P and vector angle. Mean annual temperature (MAT) was negatively correlated with enzyme N:P and vector angle but had less effect on plant C:N:P stoichiometry. In conclusion, heavy drought intensity and long duration attenuated the P limitation in the shoot but enhanced the microbial N limitation.