气候变化领域集成服务门户(CCPortal): Drought-induced regime shift and resilience of a Sahelian ecohydrosystem

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DOI	10.1088/1748-9326/ab3dde
	Drought-induced regime shift and resilience of a Sahelian ecohydrosystem
	Wendling V.; Peugeot C.; Mayor A.G.; Hiernaux P.; Mougin E.; Grippa M.; Kergoat L.; Walcker R.; Galle S.; Lebel T.
发表日期	2019
ISSN	17489318
卷号	14 期号:10
英文摘要	The Sahel (a semi-arid fringe south of the Sahara) experienced a long and prolonged drought from the 1970s to the mid-1990s, with a few extremely severe episodes that strongly affected ecosystems and societies. Long-term observations showed that surface runoff increased during this period, despite the rainfall deficit. This paradox stems from the soil degradation that was induced by various factors, either directly linked to the drought (impact on vegetation cover), or, in places, to human practices (land clearing and cropping). Surface runoff is still increasing throughout the region, suggesting that Sahelian ecohydrosystems may have shifted to a new hydrological regime. In order to explore this issue, we have developed a simple system dynamics model incorporating vegetation-hydrology interactions and representing in a lumped way the first order processes occurring at the hillslope scale and the annual timestep. Long term observations on a pilot site in northern Mali were used to constrain the model and define an ensemble of plausible simulations. The model successfully reproduced the vegetation collapse and the runoff increase observed over the last 60 years. Our results confirmed that the system presents two alternative states and that during the drought it shifted from a high-vegetation/low-runoff regime to the alternative low-vegetation/high-runoff one, where it has remained trapped until now. We showed that the mean annual rainfall deficit was sufficient to explain the shift. According to the model, vegetation recovery and runoff reduction are possible in this system, but the conditions in which they could occur remain uncertain as the model was only constrained by observations over the collapse trajectory. The study shows that the system is also sensitive to the interannual and decadal variability of rainfall, and that larger variability leads to higher runoff. Both mean rainfall and rainfall variability may increase in central Sahel under climate change, leading to antagonist effects on the system, which makes its resilience uncertain. © 2019 The Author(s). Published by IOP Publishing Ltd.
英文关键词	alternative stable states; eco-hydrology; rainfall variability; regime shifts; Sahel
语种	英语
scopus关键词	Climate change; Drought; Rain; Runoff; Alternative state; Antagonist effects; Decadal variability; First-order process; Hydrological regime; Long term observations; Rainfall variability; Vegetation recovery; Vegetation; annual variation; climate change; decadal variation; drought; ecosystem resilience; hillslope; hydrological regime; long-term change; rainfall; runoff; soil degradation; Mali; Sahara; Sahel [Sub-Saharan Africa]
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154353
作者单位	Hydrosciences Montpellier (HSM), IRD, Univ. Montpellier, CNRS, Montpellier, France; Copernicus Institute of Sustainable Development Géosciences Environnement, Utrecht Univ., Utrecht, Netherlands; Géosciences Environnement Toulouse (GET), CNRS, IRD, UPS, Toulouse, France; Laboratoire Écologie Fonctionnelle et Environnement (ECOLAB), UPS, CNRS, Toulouse-INP, Toulouse, France; Univ. Grenoble Alpes, CNRS, IRD, Grenoble INP, UMR IGE, Grenoble, France
推荐引用方式 GB/T 7714	Wendling V.,Peugeot C.,Mayor A.G.,et al. Drought-induced regime shift and resilience of a Sahelian ecohydrosystem[J],2019,14(10).
APA	Wendling V..,Peugeot C..,Mayor A.G..,Hiernaux P..,Mougin E..,...&Lebel T..(2019).Drought-induced regime shift and resilience of a Sahelian ecohydrosystem.Environmental Research Letters,14(10).
MLA	Wendling V.,et al."Drought-induced regime shift and resilience of a Sahelian ecohydrosystem".Environmental Research Letters 14.10(2019).