Peking Univ., Beijing (China). Sino-French Inst. for Earth System Science, College of Urban and Environmental Sciences
Peking Univ., Beijing (China). Sino-French Inst. for Earth System Science, College of Urban and Environmental Sciences; Chinese Academy of Sciences (CAS), Beijing (China). Key Lab. of Alpine Ecology and Biodiversity, Inst. of Tibetan Plateau Research, Center for Excellence in
Tibetan Earth Science
Lab. des Sciences du Climat et de l'Environnement (LSCE), Gif-sur-Yvette (France)
CSIRO Land and Water Flagship, Canberra, ACT (Australia)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division
Montana State Univ., Bozeman, MT (United States). Inst. on Ecosystems and the Dept. of Ecology
CSIRO Ocean and Atmosphere Flagship, Aspendale, Vic. (Australia)
Defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), ecosystem-scale water-use efficiency (EWUE) is an indicator of the adjustment of vegetation photosynthesis to water loss. The processes controlling EWUE are complex and reflect both a slow evolution of plants and plant communities as well as fast adjustments of ecosystem functioning to changes of limiting resources. Here in this study, we investigated EWUE trends from 1982 to 2008 using data-driven models derived from satellite observations and process-oriented carbon cycle models. Our findings suggest positive EWUE trends of 0.0056, 0.0007 and 0.0001g Cm-2mm-1yr-1 under the single effect of rising CO2 (CO2'), climate change (CLIM') and nitrogen deposition (NDEP'), respectively. Global patterns of EWUE trends under different scenarios suggest that (i) EWUE-CO2 shows global increases, (ii) EWUE-CLIM increases in mainly high latitudes and decreases at middle and low latitudes, (iii) EWUE-NDEP displays slight increasing trends except in west Siberia, eastern Europe, parts of North America and central Amazonia. The data-driven MTE model, however, shows a slight decline of EWUE during the same period (-0.0005g Cm-2mm-1yr-1), which differs from process-model (0.0064g Cm-2mm-1yr-1) simulations with all drivers taken into account. We attribute this discrepancy to the fact that the nonmodeled physiological effects of elevated CO2 reducing stomatal conductance and transpiration (TR) in the MTE model. Partial correlation analysis between EWUE and climate drivers shows similar responses to climatic variables with the data-driven model and the process-oriented models across different ecosystems. Change in water-use efficiency defined from transpiration-based WUEt (GPP/TR) and inherent water-use efficiency (IWUEt, GPPxVPD/TR) in response to rising CO2, climate change, and nitrogen deposition are also discussed. In conclusion, our analyses will facilitate mechanistic understanding of the carbon-water interactions over terrestrial ecosystems under global change.
Huang, Mengtian, et al. "Change in terrestrial ecosystem water-use efficiency over the last three decades." Global Change Biology, vol. 21, no. 6, Jan. 2015. https://doi.org/10.1111/gcb.12873
Huang, Mengtian, Piao, Shilong, Sun, Yan, et al., "Change in terrestrial ecosystem water-use efficiency over the last three decades," Global Change Biology 21, no. 6 (2015), https://doi.org/10.1111/gcb.12873
@article{osti_1348304,
author = {Huang, Mengtian and Piao, Shilong and Sun, Yan and Ciais, Philippe and Cheng, Lei and Mao, Jiafu and Poulter, Ben and Shi, Xiaoying and Zeng, Zhenzhong and Wang, Yingping},
title = {Change in terrestrial ecosystem water-use efficiency over the last three decades},
annote = {Defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), ecosystem-scale water-use efficiency (EWUE) is an indicator of the adjustment of vegetation photosynthesis to water loss. The processes controlling EWUE are complex and reflect both a slow evolution of plants and plant communities as well as fast adjustments of ecosystem functioning to changes of limiting resources. Here in this study, we investigated EWUE trends from 1982 to 2008 using data-driven models derived from satellite observations and process-oriented carbon cycle models. Our findings suggest positive EWUE trends of 0.0056, 0.0007 and 0.0001g Cm-2mm-1yr-1 under the single effect of rising CO2 (CO2'), climate change (CLIM') and nitrogen deposition (NDEP'), respectively. Global patterns of EWUE trends under different scenarios suggest that (i) EWUE-CO2 shows global increases, (ii) EWUE-CLIM increases in mainly high latitudes and decreases at middle and low latitudes, (iii) EWUE-NDEP displays slight increasing trends except in west Siberia, eastern Europe, parts of North America and central Amazonia. The data-driven MTE model, however, shows a slight decline of EWUE during the same period (-0.0005g Cm-2mm-1yr-1), which differs from process-model (0.0064g Cm-2mm-1yr-1) simulations with all drivers taken into account. We attribute this discrepancy to the fact that the nonmodeled physiological effects of elevated CO2 reducing stomatal conductance and transpiration (TR) in the MTE model. Partial correlation analysis between EWUE and climate drivers shows similar responses to climatic variables with the data-driven model and the process-oriented models across different ecosystems. Change in water-use efficiency defined from transpiration-based WUEt (GPP/TR) and inherent water-use efficiency (IWUEt, GPPxVPD/TR) in response to rising CO2, climate change, and nitrogen deposition are also discussed. In conclusion, our analyses will facilitate mechanistic understanding of the carbon-water interactions over terrestrial ecosystems under global change.},
doi = {10.1111/gcb.12873},
url = {https://www.osti.gov/biblio/1348304},
journal = {Global Change Biology},
issn = {ISSN 1354-1013},
number = {6},
volume = {21},
place = {United States},
publisher = {Wiley},
year = {2015},
month = {01}}