A synthesis of ecosystem aboveground productivity and its process variables under simulated drought stress

作者：Jiangbo Gao, Linlin Zhang, Ze Tang, Shaohong Wu · 发表于：Journal of Ecology · 年份：2019 · DOI：10.1111/1365-2745.13218 · 被引用次数：85 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Ecology and Vegetation Dynamics Studies

Abstract Projected increases in drought duration and intensity under climate change considerably affect aboveground productivity (ANPP) and associated process variables (photosynthesis rates ( P n ), stomatal conductance ( g s ), soil respiration ( R s) and soil water content (SWC)). Although ANPP has been extensively studied across the ecosystems, there is a little consensus on how the spatiotemporal patterns of ANPP will be altered with increasing drought stress. Here, we present a global meta‐analysis of ANPP and the four variables (610 observations from 78 studies) for drought duration, intensity and their combination. Forest‐ANPP had stronger negative responses to long‐term drought (34.44%; ≥4 years) than short‐term drought (10.78%; ≤1 year) and decreased more in Mediterranean forests than in tropical forests. Decreases in P n and g s were strongest under long‐term moderate drought. In the short term, R s increased by 5.66% under light drought, but decreased by 14.12% and 28.43% under moderate and severe droughts. Grass‐ANPP showed a nonlinear decrease with extended duration and the rate slowed. Within light to severe intensities, ANPP decreased linearly, but became stable under extreme condition. In the short term, ANPP reduced more seriously with increasing drought intensity (12.01%‐30.34%). With aggravation of drought stress, the reductions in R s and SWC increased. There was significant heterogeneity in grassland responses to drought stress. The greatest decreases in...