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Quantifying the effects of elevated CO 2 on water budgets by combining FACE data with an ecohydrological model
Author(s) -
Cheng Lei,
Zhang Lu,
Wang YingPing,
Yu Qiang,
Eamus Derek
Publication year - 2014
Publication title -
ecohydrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.982
H-Index - 54
eISSN - 1936-0592
pISSN - 1936-0584
DOI - 10.1002/eco.1478
Subject(s) - transpiration , environmental science , evapotranspiration , leaf area index , interception , vegetation (pathology) , water content , soil water , hydrology (agriculture) , stomatal conductance , precipitation , atmospheric sciences , agronomy , soil science , photosynthesis , ecology , chemistry , medicine , biochemistry , geotechnical engineering , physics , pathology , geology , meteorology , biology , engineering
Response of leaf area index (LAI) is the key determinant for predicting impacts of the elevated CO 2 (eCO 2 ) on water budgets. Importance of the changes in functional attributes of vegetation associated with eCO 2 for predicting responses of LAI has rarely been addressed. In this study, the WAter Vegetation Energy and Solute (WAVES) model was applied to simulate ecohydrological effects of the eCO 2 at two free‐air CO 2 enrichment (FACE) experimental sites with contrasting vegetation. One was carried out by the Oak Ridge National Laboratory on the forest (ORNL FACE). The other one was conducted by the University of Minnesota on the grass (BioCON FACE). Results demonstrated that changes in functional attributes of vegetation (including reduction in specific leaf area, changes in carbon assimilation and allocation characteristics) and availability of nutrients are important for reproducing the responses of LAI, transpiration and soil moisture at both sites. Predicted LAI increased slightly at both sites because of fertilization effects of the eCO 2 . Simulated transpiration decreased 10·5% at ORNL site and 13·8% at BioCON site because of reduction in the stomatal conductance. Predicted evaporation from interception and soil surface increased slightly (<1·0 mm year −1 ) at both sites because of increased LAI and litter production, and increased soil moisture resulted from reduced transpiration. All components of run‐off were predicted to increase because of significant decrease in transpiration. Simulated mean annual evapotranspiration decreased about 8·7% and 10·8%, and mean annual run‐off increased about 11·1% (59·3 mm year −1 ) and 9·5% (37·6 mm year −1 ) at the ORNL and BioCON FACE sites, respectively. Copyright © 2014 John Wiley & Sons, Ltd.