Reduced transpiration response to precipitation pulses precedes mortality in a piñon–juniper woodland subject to prolonged drought

Global climate change is predicted to alter the intensity and duration of droughts, but the effects of changing precipitation patterns on vegetation mortality are difficult to predict. Our objective was to determine whether prolonged drought or above-average precipitation altered the capacity to res...

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Bibliographic Details
Published in:The New phytologist 2013-10, Vol.200 (2), p.375-387
Main Authors: Plaut, Jennifer A., Wadsworth, W. Duncan, Pangle, Robert, Yepez, Enrico A., McDowell, Nate G., Pockman, William T.
Format: Article
Language:English
Subjects:
Additives
Agricultural Irrigation
Atmospheric precipitations
Carbon - metabolism
carbon starvation
Climate change
Climate prediction
die‐off
Drought
Droughts
Ecosystem
hydraulic conductance
hydraulic failure
Hydraulics
Irrigation
Juniperus - physiology
mixed effects model
Modeling
Models, Theoretical
Mortality
New Mexico
Pinus
Pinus - physiology
Plant Transpiration - physiology
Precipitation
Pulse irrigation
Rain
Rainfall
semi‐arid
Soil
Soil moisture
Soil water
Survival
Transpiration
Trees
Vapor Pressure
Vapour pressure
Woodlands
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Summary:Global climate change is predicted to alter the intensity and duration of droughts, but the effects of changing precipitation patterns on vegetation mortality are difficult to predict. Our objective was to determine whether prolonged drought or above-average precipitation altered the capacity to respond to the individual precipitation pulses that drive productivity and survival. We analyzed 5 yr of data from a rainfall manipulation experiment in piñon–juniper (Pinus edulis–Juniperus monosperma) woodland using mixed effects models of transpiration response to event size, antecedent soil moisture, and post-event vapor pressure deficit. Replicated treatments included irrigation, drought, ambient control and infrastructure control. Mortality was highest under drought, and the reduced post-pulse transpiration in the droughted trees that died was attributable to treatment effects beyond drier antecedent conditions and reduced event size. In particular, trees that died were nearly unresponsive to antecedent shallow soil moisture, suggesting reduced shallow absorbing root area. Irrigated trees showed an enhanced response to precipitation pulses. Prolonged drought initiates a downward spiral whereby trees are increasingly unable to utilize pulsed soil moisture. Thus, the additive effects of future, more frequent droughts may increase drought-related mortality.
ISSN:0028-646X
1469-8137
DOI:10.1111/nph.12392