Exploring complex water stress–gross primary production relationships: Impact of climatic drivers, main effects, and interactive effects

作者：Huan Wang, Shijie Yan, Philippe Ciais, Jean‐Pierre Wigneron, Laibao Liu, Yan Li, Zheng Fu, Hongliang Ma, Ze Liang, Feili Wei, Yueyao Wang, Shuangcheng Li · 发表于：Global Change Biology · 年份：2022 · DOI：10.1111/gcb.16201 · 被引用次数：170 · 研究领域：Plant Water Relations and Carbon Dynamics、Climate variability and models、Tree-ring climate responses

Abstract The dominance of vapor pressure deficit (VPD) and soil water content (SWC) for plant water stress is still under debate. These two variables are strongly coupled and influenced by climatic drivers. The impacts of climatic drivers on the relationships between gross primary production (GPP) and water stress from VPD/SWC and the interaction between VPD and SWC are not fully understood. Here, applying statistical methods and extreme gradient boosting models—Shapley additive explanations framework to eddy‐covariance observations from the global FLUXNET2015 data set, we found that the VPD‐GPP relationship was strongly influenced by climatic interactions and that VPD was more important for plant water stress than SWC across most plant functional types when we removed the effect of main climatic drivers, e.g. air temperature, incoming shortwave radiation and wind speed. However, we found no evidence for a significant influence of elevated CO 2 on stress alleviation, possibly because of the short duration of the records (approximately one decade). Additionally, the interactive effect between VPD and SWC differed from their individual effect. When SWC was high, the SHAP interaction value of SWC and VPD on GPP was decreased with increasing VPD, but when SWC was low, the trend was the opposite. Additionally, we revealed a threshold effect for VPD stress on GPP loss; above the threshold value, the stress on GPP was flattened off. Our results have important implications for indepe...