Spatiotemporal responses of net primary productivity of alpine ecosystems to flash drought: The Qilian Mountains

Understanding the impact of high-altitude flash droughts on vegetation net primary productivity (NPP) is crucially important for ecosystem management. Here, we investigated the response of NPP to flash drought with a case of the Qilian Mountains (QLMs). Our results indicated that the intensity of flash drought in the QLMs increased significantly during 1982–2018, and NPP was highly sensitive to flash drought, with 64.3 % (124,245 km2) of the region showing highly negative responses. The partial correlation analysis between NPP and meteorological factors in terms of different drought intensities showed that intensified flash drought enhanced the coupling between NPP and temperature/VPD. In the short-duration flash drought events with positive temperature anomalies, temperature increase will promote the accumulation of NPP; however, the carbon uptake of plants was significantly compromised by VPD in the flash drought events with negative temperature anomalies. Our study may provide valuable information for drought monitoring and comprehensive ecosystem management.