Divergent trends of ecosystem‐scale photosynthetic efficiency between arid and humid lands across the globe

作者：Fangli Wei, Shuai Wang, Bojie Fu, Lanhui Wang, Wenmin Zhang, Lixin Wang, Ning Pan, Rasmus Fensholt · 发表于：Global Ecology and Biogeography · 年份：2022 · DOI：10.1111/geb.13561 · 被引用次数：34 · 研究领域：Remote Sensing in Agriculture、Plant Water Relations and Carbon Dynamics、Plant responses to elevated CO2

Abstract Aim Widespread greening and an increasing global terrestrial carbon sink over recent decades have been reported. However, the spatio‐temporal relationships between vegetation greenness and productivity and the factors influencing this relationship remain unclear. We define a new metric of ecosystem‐scale photosynthetic efficiency (EPE) to analyse its spatio‐temporal pattern and investigate how potential drivers regulate the greenness–productivity relationship. Location Global. Time period From 2001 to 2016. Major taxa studied Global terrestrial ecosystems. Methods This study used global datasets of leaf area index (LAI) and solar‐induced fluorescence (SIF) as proxies of vegetation greenness and ecosystem productivity, respectively, to propose a new metric of SIF/LAI, representing ecosystem‐scale photosynthetic efficiency (EPE). We identified the spatial pattern and dynamics of EPE and examined factors influencing EPE. Results The results showed a weaker increase in productivity compared with the global greening rate from 2001 to 2016, suggesting a decline in EPE at the global scale. This decline in EPE indicates a disproportionate increase in terrestrial productivity against the widespread greening. When stratified into areas following an aridity gradient, we found that EPE overall showed upward trends in arid and semi‐arid areas, and downward trends in dry sub‐humid and humid regions. The EPE was controlled primarily by soil moisture, which promoted or constrained t...