eCite Digital Repository
Exposure of trees to drought-induced die-off is defined by a common climatic threshold across different vegetation types
Citation
Mitchell, P and O'Grady, AP and Hayes, KR and Pinkard, EA, Exposure of trees to drought-induced die-off is defined by a common climatic threshold across different vegetation types, Ecology and Evolution, 4, (7) pp. 1088-1101. ISSN 2045-7758 (2014) [Refereed Article]
![]() | PDF 2Mb |
Copyright Statement
Copyright 2014 The Authors. Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) https://creativecommons.org/licenses/by/3.0/
Abstract
Increases in drought and temperature stress in forest and woodland ecosystems are thought to be responsible for the rise in episodic mortality events observed globally. However, key climatic drivers common to mortality events and the impacts of future extreme droughts on tree survival have not been evaluated. Here, we characterize climatic drivers associated with documented tree die-off events across Australia using standardized climatic indices to represent the key dimensions of drought stress for a range of vegetation types. We identify a common probabilistic threshold associated with an increased risk of die-off across all the sites that we examined. We show that observed die-off events occur when water deficits and maximum temperatures are high and exist outside 98% of the observed range in drought intensity; this threshold was evident at all sites regardless of vegetation type and climate. The observed die-off events also coincided with at least one heat wave (three consecutive days above the 90th percentile for maximum temperature), emphasizing a pivotal role of heat stress in amplifying tree die-off and mortality processes. The joint drought intensity and maximum temperature distributions were modeled for each site to describe the co-occurrence of both hot and dry conditions and evaluate future shifts in climatic thresholds associated with the die-off events. Under a relatively dry and moderate warming scenario, the frequency of droughts capable of inducing significant tree die-off across Australia could increase from 1 in 24 years to 1 in 15 years by 2050, accompanied by a doubling in the occurrence of associated heat waves. By defining commonalities in drought conditions capable of inducing tree die-off, we show a strong interactive effect of water and high temperature stress and provide a consistent approach for assessing changes in the exposure of ecosystems to extreme drought events.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | drought, extreme events, forest die-off, heat waves, tree mortality |
Research Division: | Biological Sciences |
Research Group: | Plant biology |
Research Field: | Plant physiology |
Objective Division: | Environmental Management |
Objective Group: | Fresh, ground and surface water systems and management |
Objective Field: | Assessment and management of freshwater ecosystems |
UTAS Author: | Mitchell, P (Dr Patrick Mitchell) |
UTAS Author: | O'Grady, AP (Dr Anthony O'Grady) |
ID Code: | 120122 |
Year Published: | 2014 |
Web of Science® Times Cited: | 64 |
Deposited By: | Plant Science |
Deposited On: | 2017-08-10 |
Last Modified: | 2017-09-27 |
Downloads: | 124 View Download Statistics |
Repository Staff Only: item control page