Modelled effects of precipitation on ecosystem carbon and water dynamics in different climatic zones

Gerten Dieter, Luo Yiqi, Le Maire Guerric, Parton W.J., Keough Cindy, Weng Ensheng, Beier Claus, Ciais Philippe, Cramer Wolfgang, Dukes Jeffrey S., Hanson P. J., Knapp Alan A. K., Linder Sune, Nepstad Dan, Rustad Lindsey, Sowerby Alwyn. 2008. Modelled effects of precipitation on ecosystem carbon and water dynamics in different climatic zones. Global Change Biology, 14 (10) : 2365-2379.

Résumé : The ongoing changes in the global climate expose the world's ecosystems not only to increasing CO2 concentrations and temperatures but also to altered precipitation (P) regimes. Using four well-established process-based ecosystem models (LPJ, DayCent, ORCHIDEE, TECO), we explored effects of potential P changes on water limitation and net primary production (NPP) in seven terrestrial ecosystems with distinctive vegetation types in different hydroclimatic zones. We found that NPP responses to P changes differed not only among sites but also within a year at a given site. The magnitudes of NPP change were basically determined by the degree of ecosystem water limitation, which was quantified here using the ratio between atmospheric transpirational demand and soil water supply. Humid sites and/or periods were least responsive to any change in P as compared with moderately humid or dry sites/periods. We also found that NPP responded more strongly to doubling or halving of P amount and a seasonal shift in P occurrence than that to altered P frequency and intensity at constant annual amounts. The findings were highly robust across the four models especially in terms of the direction of changes and largely consistent with earlier P manipulation experiments and modelling results. Overall, this study underscores the widespread importance of P as a driver of change in ecosystems, although the ultimate response of a particular site will depend on the detailed nature and seasonal timing of P change.

Mots-clés Agrovoc : modèle de simulation, modélisation environnementale, précipitation, changement climatique, zone climatique, carbone, eau, variation saisonnière, facteur du milieu, écosystème, stress dû à la sécheresse, respiration du sol, sécheresse

Classification Agris : P40 - Météorologie et climatologie
F40 - Écologie végétale

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Gerten Dieter, Potsdam Institute for Climate Impact Research (DEU)
• Luo Yiqi, University of Oklahoma (USA)
• Le Maire Guerric, CIRAD-PERSYST-UPR Ecosystèmes de plantations (FRA) ORCID: 0000-0002-5227-958X
• Parton W.J., University of Colorado (USA)
• Keough Cindy, University of Colorado (USA)
• Weng Ensheng, University of Oklahoma (USA)
• Beier Claus, Technical University of Denmark (DNK)
• Ciais Philippe, CNRS (FRA)
• Cramer Wolfgang, Potsdam Institute for Climate Impact Research (DEU)
• Dukes Jeffrey S., University of Massachusetts (USA)
• Hanson P. J., Oak Ridge National Laboratory (USA)
• Knapp Alan A. K., Colorado State University (USA)
• Linder Sune, Swedish University of Agricultural Sciences (SWE)
• Nepstad Dan, WHRC (USA)
• Rustad Lindsey, USDA (USA)
• Sowerby Alwyn, Centre for Ecology and Hydrology (GBR)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/546769/)

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