Changes in precipitation have both direct and indirect effects on typical steppe aboveground net primary productivity in Loess Plateau, China

Background and aims Changes in precipitation profoundly affect ecological processes of steppe ecosystem. To predict the impact of climate changes on plant aboveground net primary productivity (ANPP), it is necessary to understand the direct and indirect effects of precipitation changes on ANPP. Methods In this study, a precipitation manipulation experiment (i.e., R100: ambient precipitation as a control, R50: 50% of ambient precipitation, R150: 150% of ambient precipitation) was conducted in 2017 in a typical steppe in the western Loess Plateau, China. The ANPP, below-ground biomass, species diversity, vegetation cover, and soil properties of natural grassland were determined in 2020. The structural equation model (SEM) was used to compare the relative contribution of plant and soil properties to ANPP. Results We found that the vegetation cover, diversity index, community richness, and biomass were positively correlated with precipitation gradients; The soil moisture, soil available potassium (SAK), and soil total phosphorus were significantly affected by changing precipitation. Our findings revealed that changes in precipitation had a significant positive effect on ANPP, which was mainly mediated by community coverage according to SEM. Conclusion Our results emphasize the importance of vegetation cover in driving the short-term response of ANPP to climate change in the typical steppe. The study is critical to understand the functioning and stability of grassland ecosystems under changing climates.