Global patterns of extreme drought-induced loss in land primary production: Identifying ecological extremes from rain-use efficiency

• Published in: The Science of the total environment 2018-07, Vol.628-629 (C), p.611-620
• Main Authors: Du, Ling, Mikle, Nathaniel, Zou, Zhenhua, Huang, Yuanyuan, Shi, Zheng, Jiang, Lifen, McCarthy, Heather R., Liang, Junyi, Luo, Yiqi
• Format: Article
• Language: English
• Subjects: Continental interfaces, environment; Ecosystem function; ENVIRONMENTAL SCIENCES; Extreme drought; GPP; Interannual variation; Ocean, Atmosphere; Rain-use efficiency; Sciences of the Universe; Semi-arid regions
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.02.114

•A novel method was developed to detect extreme drought-induced loss of ecosystem function globally.•Large well-known extreme drought events were detected mainly in semi-arid regions.•GPP reduction caused by functional loss could explain ≥70% of the interannual variation in GPP in drought-affected areas. [Display omitted] Quantifying the ecological patterns of loss of ecosystem function in extreme drought is important to understand the carbon exchange between the land and atmosphere. Rain-use efficiency [RUE; gross primary production (GPP)/precipitation] acts as a typical indicator of ecosystem function. In this study, a novel method based on maximum rain-use efficiency (RUEmax) was developed to detect losses of ecosystem function globally. Three global GPP datasets from the MODIS remote sensing data (MOD17), ground upscaling FLUXNET observations (MPI-BGC), and process-based model simulations (BESS), and a global gridded precipitation product (CRU) were used to develop annual global RUE datasets for 2001–2011. Large, well-known extreme drought events were detected, e.g. 2003 drought in Europe, 2002 and 2011 drought in the U.S., and 2010 drought in Russia. Our results show that extreme drought-induced loss of ecosystem function could impact 0.9% ± 0.1% of earth's vegetated land per year and was mainly distributed in semi-arid regions. The reduced carbon uptake caused by functional loss (0.14 ± 0.03 PgC/yr) could explain >70% of the interannual variation in GPP in drought-affected areas (p ≤ 0.001). Our results highlight the impact of ecosystem function loss in semi-arid regions with increasing precipitation variability and dry land expansion expected in the future.