Transpiration dynamics support resource partitioning in African savanna trees and grasses

dc.citation.doi10.1890/14-1986.1
dc.citation.epage1472
dc.citation.issn0012-9658
dc.citation.issue6
dc.citation.jtitleEcology
dc.citation.spage1466
dc.citation.volume96
dc.contributor.authorHoldo, R. M.
dc.contributor.authorNippert, Jesse B.
dc.contributor.authoreidnippert
dc.date.accessioned2016-04-04T22:13:50Z
dc.date.available2016-04-04T22:13:50Z
dc.date.published2015
dc.descriptionCitation: Holdo, R. M., & Nippert, J. B. (2015). Transpiration dynamics support resource partitioning in African savanna trees and grasses. Ecology, 96(6), 1466-1472. doi:10.1890/14-1986.1
dc.descriptionIt is still far from clear whether and to what extent trees and grasses partition soil moisture in tropical savannas. A major reason for this is that we don't know how snapshot data on rooting differences translate into ecologically relevant patterns of water use at seasonal scales. We used stable isotopes in soil and stem water to quantify functional rooting profiles in grasses and two tree species in a South African savanna. Concurrently, we measured tree sap-flow velocity, grass canopy temperature (a transpiration correlate), and soil moisture content at multiple depths over the course of a growing season. We used lasso regression to identify the dominant soil moisture layers driving daily variation in tree and grass water-use metrics while controlling for weather variables. We found clear rooting depth differences between grasses (shallow) and trees (deep) from the isotopic data, and these patterns were strongly supported by the water-use data, which showed that grasses and trees predominantly responded to soil moisture availability at 5 and 40 cm depth, respectively. Our results provide a rare example of mechanistic support for the resource partitioning hypothesis in savannas, with important implications for our understanding of tree-grass dynamics under altered precipitation regimes.
dc.identifier.urihttp://hdl.handle.net/2097/32241
dc.relation.urihttps://doi.org/10.1890/14-1986.1
dc.rightsCopyright by the Ecological Society of America
dc.rights.urihttp://www.sherpa.ac.uk/romeo/issn/0012-9658/
dc.subjectCanopy Temperature
dc.subjectLasso Regression
dc.subjectNiche Partitioning
dc.subjectRooting Depth
dc.subjectSap Flow
dc.subjectSouth Africa
dc.titleTranspiration dynamics support resource partitioning in African savanna trees and grasses
dc.typeArticle

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