Process‐Based Modelling of Vegetation‐Climate Synergies Driving Evapotranspiration Dynamics in Karst Ecosystems

ABSTRACT Evapotranspiration (ET), a critical element of regional hydrological cycles and energy balances, connects terrestrial ecological and hydrological processes in karst ecosystems. Following large‐scale ecological restoration, Guangxi's significant vegetation changes have altered regional energy‐water dynamics via enhanced ET. This study applied a process‐based PT‐JPL model with locally optimized parameters to quantify ET dynamics and vegetation change impacts in Guangxi (2001–2018). Using the Geodetector method, we investigated single‐factor controls and synergistic interactions between vegetation/climate drivers. The results of this study showed that the parameter‐optimized PT‐JPL model has good accuracy in Guangxi. The actual ET of Guangxi showed an increasing trend with a rate of 3.5 mm a −1 from 2001 to 2018. The changes in vegetation significantly increased regional ET in Guangxi. The average annual ET under vegetation changes was 7.4 mm higher than that under constant vegetation compared to no change in vegetation. The changes in ET are not the effect of the influencing factor alone but the synergistic effect of influencing factors. The synergistic effect of Rad and LAI on ET was found to be very significant using the Geodetector's interactive detector.