Groundwater thresholds for drought resilience in floodplain woodlands: a case study from the northern Murray-Darling Basin

Kath, Jarrod ORCID: and Reardon-Smith, Kate and Le Brocque, Andy and Dyer, Fiona (2014) Groundwater thresholds for drought resilience in floodplain woodlands: a case study from the northern Murray-Darling Basin. In: Climate Adaptation (NCCARF 2014): Future Challenges, 30 Sep-2 Oct 2014, Gold Coast, Australia.

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In ephemeral river systems, canopy condition in dominant
riparian and floodplain tree species may depend on access
to shallow groundwater resources, particularly during
drought. However, unsustainable groundwater extraction and
chronic groundwater decline, evident in many agricultural
landscapes worldwide, effectively decouples tree roots from
deep soil moisture resources, increasing the susceptibility
of trees to changes in precipitation.
In such regions, drought may trigger loss of canopy
condition and have long term consequences for the function
and survival of trees and the composition, structure and
function of ecosystems they dominate. However, critical groundwater depth thresholds have been difficult to identify.
This study used a novel approach including boosted regression trees, quantile regression and threshold
analysis to explore the relationship between groundwater
depth and tree condition for two dominant tree species,
Eucalyptus camaldulensis (river red gum) and E. populnea
(poplar box); both species occur on the Upper Condamine
floodplain, a region experiencing groundwater depth
declines of 25+m in the northern Murray-­‐Darling Basin,
southern Queensland.
Distinct non-­‐linear responses were apparent, with minimum
groundwater depth thresholds identified at 12.1m for E.
camaldulensis and 12.6m for E.populnea, beyond which canopy
condition declined significantly.
This approach represents a repeatable method of quantifying
ecological response thresholds along groundwater depth
gradients. Its application may enable safe operating limits for groundwater resource management to be identified, supporting improved decision making to support resilient floodplain ecosystems.
This will be particularly important in regions where
groundwater decline driven by increasing water demand and
drying climates is predicted.

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Lecture)
Refereed: Yes
Item Status: Live Archive
Additional Information: © National Climate Change Adaptation Research Facility 2014. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 05 May 2015 02:34
Last Modified: 16 May 2017 00:03
Uncontrolled Keywords: Australia; Murray River; Darling River; groundwater decline; Condamine district; native trees
Fields of Research (2008): 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
05 Environmental Sciences > 0502 Environmental Science and Management > 050209 Natural Resource Management
05 Environmental Sciences > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change
Fields of Research (2020): 37 EARTH SCIENCES > 3707 Hydrology > 370799 Hydrology not elsewhere classified
41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410406 Natural resource management
41 ENVIRONMENTAL SCIENCES > 4101 Climate change impacts and adaptation > 410102 Ecological impacts of climate change and ecological adaptation
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9603 Climate and Climate Change > 960307 Effects of Climate Change and Variability on Australia (excl. Social Impacts)

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