Water‐use efficiency in a semi‐arid woodland with high rainfall variability

Tarin Terrazas, T; Nolan, RH; Medlyn, BE; Cleverly, J; Eamus, D

Water‐use efficiency in a semi‐arid woodland with high rainfall variability

Tarin Terrazas, T Nolan, RH Medlyn, BE Cleverly, J

Eamus, D

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Publisher:: Wiley
Publication Type:: Journal Article
Citation:: Global Change Biology, 2020, 26, (2), pp. 496-508
Issue Date:: 2020-02-06

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Field	Value	Language
dc.contributor.author	Tarin Terrazas, T
dc.contributor.author	Nolan, RH
dc.contributor.author	Medlyn, BE
dc.contributor.author	Cleverly, J https://orcid.org/0000-0002-2731-7150
dc.contributor.author	Eamus, D https://orcid.org/0000-0003-2765-8040
dc.date.accessioned	2020-10-16T02:56:23Z
dc.date.available	2019-10-03
dc.date.available	2020-10-16T02:56:23Z
dc.date.issued	2020-02-06
dc.identifier.citation	Global Change Biology, 2020, 26, (2), pp. 496-508
dc.identifier.issn	1354-1013
dc.identifier.issn	1365-2486
dc.identifier.uri	http://hdl.handle.net/10453/143292
dc.description.abstract	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.
dc.format	Print-Electronic
dc.language	en
dc.publisher	Wiley
dc.relation	http://purl.org/au-research/grants/arc/DP140101150
dc.relation	Department of Innovation, Industry, Science & Research
dc.relation	Commonwealth Scientific and Industrial Research Organisation
dc.relation	Department of Innovation, Industry, Science & Research
dc.relation	Commonwealth Scientific and Industrial Research Organisation
dc.relation	Department of Industry Skills and Regional Development
dc.relation.ispartof	Global Change Biology
dc.relation.isbasedon	10.1111/gcb.14866
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.subject	05 Environmental Sciences, 06 Biological Sciences
dc.subject.classification	Ecology
dc.subject.mesh	Water
dc.subject.mesh	Soil
dc.subject.mesh	Ecosystem
dc.subject.mesh	Photosynthesis
dc.subject.mesh	Australia
dc.subject.mesh	Forests
dc.subject.mesh	Australia
dc.subject.mesh	Ecosystem
dc.subject.mesh	Forests
dc.subject.mesh	Photosynthesis
dc.subject.mesh	Soil
dc.subject.mesh	Water
dc.title	Water‐use efficiency in a semi‐arid woodland with high rainfall variability
dc.type	Journal Article
utslib.citation.volume	26
utslib.location.activity	England
utslib.for	0601 Biochemistry and Cell Biology
utslib.for	0501 Ecological Applications
utslib.for	05 Environmental Sciences
utslib.for	06 Biological Sciences
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Students
utslib.copyright.status	closed_access	*
pubs.consider-herdc	true
dc.date.updated	2020-10-16T02:56:10Z
pubs.issue	2
pubs.publication-status	Published
pubs.volume	26
utslib.citation.issue	2

Abstract:

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.

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http://hdl.handle.net/10453/143292