Journal Article

How do leaf and ecosystem measures of water-use efficiency compare?

Duursma, Remko A, Centre National de la Recherche Scientifique (CNRS), Graduate School of Geography ; Clark University, Linderson, Maj-Lena, Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), OzFlux ; The University of Queensland (UQ [All campuses : Brisbane, Dutton Park Gatton, Herston, St Lucia and other locations]), European Project: 609398,EC:FP7:PEOPLE,FP7-PEOPLE-2013-COFUND,AGREENSKILLSPLUS, Ecologie des Forêts Méditerranéennes (URFM) ; Institut National de la Recherche Agronomique (INRA), Knauer, Jürgen, Université de Montpellier (UM), Department of Biological Science ; University of Denver, Williams, Christopher A, Meir, Patrick, Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU) ; Karlsruhe Institute of Technology = Karlsruher Institut für Technologie (KIT), de Kauwe, Martin G, Wingate, Lisa, Clement, Rob, Isaac, Peter, Hawkesbury Institute for the Environment [Richmond] (HIE

2017

Overview

The terrestrial carbon and water cycles are intimately linked: the carbon cycle is driven by photosynthesis, while the water balance is dominated by transpiration, and both fluxes are controlled by plant stomatal conductance. The ratio between these fluxes, the plant water-use efficiency (WUE), is a useful indicator of vegetation function. WUE can be estimated using several techniques, including leaf gas exchange, stable isotope discrimination, and eddy covariance. Here we compare global compilations of data for each of these three techniques. We show that patterns of variation in WUE across plant functional types (PFTs) are not consistent among the three datasets. Key discrepancies include the following: leaf-scale data indicate differences between needleleaf and broadleaf forests, but ecosystem-scale data do not; leaf-scale data indicate differences between C3 and C4 species, whereas at ecosystem scale there is a difference between C3 and C4 crops but not grasslands; and isotope-based estimates of WUE are higher than estimates based on gas exchange for most PFTs. Our study quantifies the uncertainty associated with different methods of measuring WUE, indicates potential for bias when using WUE measures to parameterize or validate models, and indicates key research directions needed to reconcile alternative measures of WUE.

• Publisher: Wiley,CCSD,New Phytologist Trust,Wiley Subscription Services, Inc,Wiley-Blackwell
• Subject: C3 plants / C4 plants / carbon / Carbon cycle / Conductance / crops / Data / data collection / Databases, Factual / deciduous forests / Ecosystem / Ecosystems / eddy covariance / Estimates / Flowers & plants / Fluxes / Forests / Gas exchange / Grasslands / Hydrologic cycle / Isotopes / leaf gas exchange / Leaves / Life Sciences / Measurement methods / Photosynthesis / plant functional type (PFT) / Plant Leaves - physiology / Plant Transpiration / Poaceae - physiology / Stable isotopes / Stomata / Stomatal conductance / Transpiration / uncertainty / Vegetal Biology / Water / Water balance / Water use / water use efficiency
• ISBN: 0004172152000