Quantifying soil moisture impacts on light use efficiency across biomes
Stocker, Benjamin (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Zscheischler, Jakob (ETH Zürich. Institute for Atmospheric and Climate Science)
Keenan, Trevor F. (University of California (Berkeley). Department of Environmental Science, Policy, and Management)
Prentice, Iain Colin (Imperial College London. Department of Life Sciences)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Seneviratne, Sonia I. (ETH Zürich. Institute for Atmospheric and Climate Science)

Date:	2018
Abstract:	Terrestrial primary productivity and carbon cycle impacts of droughts are commonly quantified using vapour pressure deficit (VPD) data and remotely sensed greenness, without accounting for soil moisture. However, soil moisture limitation is known to strongly affect plant physiology. Here, we investigate light use efficiency, the ratio of gross primary productivity (GPP) to absorbed light. We derive its fractional reduction due to soil moisture (fLUE), separated from VPD and greenness changes, using artificial neural networks trained on eddy covariance data, multiple soil moisture datasets and remotely sensed greenness. This reveals substantial impacts of soil moisture alone that reduce GPP by up to 40% at sites located in sub-humid, semi-arid or arid regions. For sites in relatively moist climates, we find, paradoxically, a muted fLUE response to drying soil, but reduced fLUE under wet conditions. fLUE identifies substantial drought impacts that are not captured when relying solely on VPD and greenness changes and, when seasonally recurring, are missed by traditional, anomaly-based drought indices. Counter to common assumptions, fLUE reductions are largest in drought-deciduous vegetation, including grasslands. Our results highlight the necessity to account for soil moisture limitation in terrestrial primary productivity data products, especially for drought-related assessments.
Grants:	European Commission 701329 European Commission 610028 European Commission 17518 Ministerio de Economía y Competitividad CGL2016-79835-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-274
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Drought impacts ; Eddy covariance ; Gross primary productivity () ; Light use efficiency ; Photosynthesis ; Soil moisture ; Standardized precipitation index ; Vapour pressure deficit
Published in:	The new phytologist, Vol. 218, issue 4 (June 2018) , p. 1430-1449, ISSN 1469-8137

DOI: 10.1111/nph.15123
PMID: 29604221

20 p, 4.2 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals) > Imbalance-P
Articles > Research articles
Articles > Published articles