DOI: 10.1111/gcb.14866
论文题名: Water-use efficiency in a semi-arid woodland with high rainfall variability
作者: Tarin T. ; Nolan R.H. ; Medlyn B.E. ; Cleverly J. ; Eamus D.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2020
卷: 26, 期: 2 语种: 英语
英文关键词: Acacia
; Australia
; carbon flux
; eddy covariance
; optimal stomatal behaviour
; photosynthesis
; stable isotopes
Scopus关键词: carbon flux
; eddy covariance
; global change
; numerical model
; photosynthesis
; rainfall
; stomatal conductance
; water use efficiency
; woodland
; Australia
; Acacia
英文摘要: As the ratio of carbon uptake to water use by vegetation, water-use efficiency (WUE) is a key ecosystem property linking global carbon and water cycles. It can be estimated in several ways, but it is currently unclear how different measures of WUE relate, and how well they each capture variation in WUE with soil moisture availability. We evaluated WUE in an Acacia-dominated woodland ecosystem of central Australia at various spatial and temporal scales using stable carbon isotope analysis, leaf gas exchange and eddy covariance (EC) fluxes. Semi-arid Australia has a highly variable rainfall pattern, making it an ideal system to study how WUE varies with water availability. We normalized our measures of WUE across a range of vapour pressure deficits using g1, which is a parameter derived from an optimal stomatal conductance model and which is inversely related to WUE. Continuous measures of whole-ecosystem g1 obtained from EC data were elevated in the 3 days following rain, indicating a strong effect of soil evaporation. Once these values were removed, a close relationship of g1 with soil moisture content was observed. Leaf-scale values of g1 derived from gas exchange were in close agreement with ecosystem-scale values. In contrast, values of g1 obtained from stable isotopes did not vary with soil moisture availability, potentially indicating remobilization of stored carbon during dry periods. Our comprehensive comparison of alternative measures of WUE shows the importance of stomatal control of fluxes in this highly variable rainfall climate and demonstrates the ability of these different measures to quantify this effect. Our study provides the empirical evidence required to better predict the dynamic carbon–water relations in semi-arid Australian ecosystems. © 2019 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/159634
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: Terrestrial Ecohydrology Research Group, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia; Department of Soil and Plant Sciences, University of Delaware, Newark, DE, United States; Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia; Terrestrial Ecosystem Research Network (TERN), University of Technology, Sydney, NSW, Australia
Recommended Citation:
Tarin T.,Nolan R.H.,Medlyn B.E.,et al. Water-use efficiency in a semi-arid woodland with high rainfall variability[J]. Global Change Biology,2020-01-01,26(2)