forest health in the drying climate of southwest western australia niels brouwers, t. lyons, g....
TRANSCRIPT
Forest health in the drying climate of southwest Western Australia
Niels Brouwers, T. Lyons, G. Hardy
• Climate change in Australia
• Climate change in southwest Western Australia (SWWA)
• Forest declines in SWWA
• Eucalyptus wandoo decline study
Overview
Temperature change
Rainfall change
Southwest of Western Australia
Temperature changes in SWWA
Rainfall changes in SWWA
Forest declines in SWWA
Eucalyptus gomphocephala (tuart) decline
Eucalyptus wandoo (wandoo) decline
Eucalyptus wandoo decline study
• Objectives
• Hypotheses
• Methods
• Results
• Discussion
Objective
• To investigate the relationship between changes in wandoo health and climate related variables
Hypotheses
• Declines in health are related to:– Decreasing rainfall
– Decreasing soil moisture availability
– Increasing temperatures
Methods
• Surveys across the geographical distribution of wandoo were carried out in 2002 and 2008
• Crown health was estimated at 123 sites
• Bureau of Meteorology data and modelled soil moisture1 were used in the analyses
1 Raupach MR, PR Briggs, V Haverd, EA King, M Paget, CM Trudinger (2008a), Australian Water Availability Project (AWAP). CSIRO Marine and Atmospheric Research Component: Final Report for Phase 3. <http://www.csiro.au/awap>.
Results & Discussion
• Declines in health are related to:– Decreasing rainfall
• Indirectly
– Decreasing soil moisture availability• Indirectly
– Increasing temperatures• Yes
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Precipitation_76.05
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Adjusted R-squared: 0.138, F-statistic: 20.54 on 1 and 121 DF, p-value: 1.384e-05
Adjusted R-squared: 0.01231, F-statistic: 2.52 on 1 and 121 DF, p-value: 0.115
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Average rainfall
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Soil_Moist_L2_76.05
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Adjusted R-squared: 0.1205 , F-statistic: 17.72 on 1 and 121 DF, p-value: 4.947e-05
Adjusted R-squared: 0.1506, F-statistic: 22.63 on 1 and 121 DF, p-value: 5.488e-06
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Max_Temp_02.07_96.01
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Adjusted R-squared: 0.6629 , F-statistic: 240.9 on 1 and 121 DF, p-value: < 2.2e-16
400 500 600 700 800 900 1000
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Average rainfall
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Conclusion
• All together this study indicates that the negative trend in wandoo health is (at least partially) driven by the changes in climate that the southwest of Western Australia has been experiencing over the last 15-30 years.
