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Stability of tropical forest tree carbon-water relations in a rainfall exclusion treatment through shifts in effective water uptake depth

Citation

Pivovaroff, AL and McDowell, NG and Barrozo Rodrigues, T and Brodribb, T and Cernusak, LA and Choat, B and Grossiord, C and Ishida, Y and Jardine, KJ and Laurance, S and Leff, R and Li, W and Liddell, M and Mackay, DS and Pacheco, H and Peters, J and de J Sampaio Filho, I and Souza, DC and Wang, W and Zhang, P and Chambers, J, Stability of tropical forest tree carbon-water relations in a rainfall exclusion treatment through shifts in effective water uptake depth, Global Change Biology, 27, (24) pp. 6454-6466. ISSN 1354-1013 (2021) [Refereed Article]


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DOI: doi:10.1111/gcb.15869

Abstract

Increasing severity and frequency of drought is predicted for large portions of the terrestrial biosphere, with major impacts already documented in wet tropical forests. Using a 4-year rainfall exclusion experiment in the Daintree Rainforest in northeast Australia, we examined canopy tree responses to reduced precipitation and soil water availability by quantifying seasonal changes in plant hydraulic and carbon traits for 11 tree species between control and drought treatments. Even with reduced soil volumetric water content in the upper 1 m of soil in the drought treatment, we found no significant difference between treatments for predawn and midday leaf water potential, photosynthesis, stomatal conductance, foliar stable carbon isotope composition, leaf mass per area, turgor loss point, xylem vessel anatomy, or leaf and stem nonstructural carbohydrates. While empirical measurements of aboveground traits revealed homeostatic maintenance of plant water status and traits in response to reduced soil moisture, modeled belowground dynamics revealed that trees in the drought treatment shifted the depth from which water was acquired to deeper soil layers. These findings reveal that belowground acclimation of tree water uptake depth may buffer tropical rainforests from more severe droughts that may arise in future with climate change.

Item Details

Item Type:Refereed Article
Keywords:drought, gas exchange, nonstructural carbohydrates, plant hydraulics, process model, rainfall exclusion, rooting depth, turgor loss point, water potentials, wet tropical forest
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Ecological physiology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Australia (excl. social impacts)
UTAS Author:Brodribb, T (Professor Tim Brodribb)
ID Code:147893
Year Published:2021
Funding Support:Australian Research Council (DP190101552)
Deposited By:Plant Science
Deposited On:2021-11-22
Last Modified:2021-11-29
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