The response of water-carbon coupling to drought stress in terrestrial ecosystems in China

Abstract

Extreme drought events have severely affected vegetation growth, but the responses of the water-carbon coupling process of vegetation in various climate zones in China to drought remain unclear. Therefore, based on WUE (Water Use Efficiency), we analyzed the responses and recovery capabilities of vegetation water-carbon coupling in various climate zones to drought stress. The results showed that 1) In terms of the drought lag time of the two, the warm and humid climate zone responds to drought events more slowly than the arid and semi-arid climate zone. On the optimal lag time, vegetation WUE and SPEI (Standardized Precipitation Evapotranspiration Index) were generally negatively correlated across climate zones. 2) The cumulative water deficit in the previous period had a medium-term cumulative effect on the vegetation WUE process in arid and semi-arid climatic zones, and a short-term cumulative effect on the WUE process in warm-humid climatic zones. 3) The resilience curve which showed that the vegetation WUE of the semi-humid and alpine arid regions had a stronger resilience to drought stress with strong recovery ability. These findings reveal the mechanism of vegetation water-carbon coupling process in response to drought, and provide an important basis for in-depth study of vegetation memory effects and adaptation strategies.