title: How is water-use efficiency of terrestrial ecosystems distributed and changing on Earth?
abstract: A better understanding of ecosystem water-use efficiency (WUE) will help us improve ecosystem management for mitigation as well as adaption to global hydrological change. Here, long-term flux tower observations of productivity and evapotranspiration allow us to detect a consistent latitudinal trend in WUE, rising from the subtropics to the northern high-latitudes. The trend peaks at approximately 51°N, and then declines toward higher latitudes. These ground-based observations are consistent with global-scale estimates of WUE. Global analysis of WUE reveals existence of strong regional variations that correspond to global climate patterns. The latitudinal trends of global WUE for Earth's major plant functional types reveal two peaks in the Northern Hemisphere not detected by ground-based measurements. One peak is located at 20° ~ 30°N and the other extends a little farther north than 51°N. Finally, long-term spatiotemporal trend analysis using satellite-based remote sensing data reveals that land-cover and land-use change in recent years has led to a decline in global WUE. Our study provides a new framework for global research on the interactions between carbon and water cycles as well as responses to natural and human impacts.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Xuguang
authors.initials: X
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Hengpeng
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, WI, USA.
authors.forename: Ankur R
authors.initials: AR
authors.lastname: Desai
authors.affiliation: MTA-SZIE Plant Ecology Research Group, Szent Istvan University, Pater K. 1., 2100 Gödöllő, Hungary.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Nagy
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Juhua
authors.initials: J
authors.lastname: Luo
authors.affiliation: School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Kolb
authors.affiliation: UMR 1114, EMMAH (Environnement Méditerranéen et Modélisation des AgroHydrosystème), INRA-UAPV, F-84 914 Avignon Cedex 9, France.
authors.forename: Albert
authors.initials: A
authors.lastname: Olioso
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Xibao
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Geographical Science, Northeast Normal University, Changchun 130024, China.
authors.forename: Li
authors.initials: L
authors.lastname: Yao
authors.affiliation: 1] Institute for Climate-Smart Agriculture, Thünen-Institute, Bundesallee 50, 38116, Braunschweig, Germany [2] ICOS Headoffice, Department of Physics, FI-00014 University of Helsinki, Finland.
authors.forename: Werner
authors.initials: W
authors.lastname: Kutsch
authors.affiliation: Department of Chemical and Biochemical Engineering, Technical University of Denmark, Roskilde, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Pilegaard
authors.affiliation: Technische Universitat Dresden, Institute of Hydrology and Meteorology, Dresden, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Köstner
authors.affiliation: Research Station Agroscope, Climate and Air Pollution Group, 8046 Zurich, Switzerland.
authors.forename: Christof
authors.initials: C
authors.lastname: Ammann
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002980:Climate; D018534:Earth, Planet; D017753:Ecosystem; D006801:Humans; D014867:Water / Q000378:metabolism*; D014881:Water Supply
chemical_list: D014867:Water; D002244:Carbon