Differential responses of ecosystem carbon flux components to experimental precipitation gradient in an alpine meadow

1. Changes in precipitation have the potential to cause dramatic changes in ecosystem carbon (C) cycling; however, it remains unclear whether different components of the net ecosystem exchange (NEE) (e.g., C uptake vs. release, plant vs. microbe respiration, aboveground vs. belowground plant respiration), have similar or differential sensitivity to precipitation gradients. 2. We conducted a manipulative field experiment (from 2015 to 2017) with six precipitation treatments, including 1/12 annual precipitation (P), 1/4 P, 1/2 P, 3/4 P, P, and 5/4 P in an alpine meadow to investigate the responses of the NEE components. 3. Over the three years, all C fluxes showed a nonlinear response to the precipitation gradients, except for root respiration. The most extreme drought treatment (1/12 P) caused strong reductions in NEE by 15.57%, gross primary productivity by 17.26%, and ecosystem respiration by 19.05%, in contrast to the control. Plant respiration was more sensitive to precipitation chan...