Esa12 extreme climatic events drive mammal irruptions
16
Aaron C. Greenville, Glenda M. Wardle and Chris R. Dickman Desert Ecology Research Group School of Biological Sciences University of Sydney Extreme climatic events drive mammal irruptions: 100-year trends in desert rainfall and temperature
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Transcript of Esa12 extreme climatic events drive mammal irruptions
Aaron C. Greenville, Glenda M. Wardle and Chris R. DickmanDesert Ecology Research Group
School of Biological SciencesUniversity of Sydney
Extreme climatic events drive mammal irruptions: 100-year trends in desert rainfall
and temperature
Extreme climatic events
Current
Climate parameter
Future
Extreme climate: spatial scale
IPCC (2007)
CSIRO & BOM (2012)
Global
Regional
Local
Aims
• To determine if extreme climate events have changed at similar rates to median events over local and regional scales.
• Determine if the frequency of large rainfall events increased.
• Are extreme climate events important for drive small mammal populations?
Methods: study region
• 11 weather stations for annual rainfall.• 4 weather stations for annual min and max
temperatures.• Small mammal trapping from Ethabuka Reserve.
Methods: climate
• Quantile regressions at 5,10, 50, 90 and 95th
• Poisson GLMM
Min Temp
1890 1920 1950 1980 2010
10
11
12
13
14
15
Alice Springs
Year
An
nu
al
min
imu
m t
emp
era
ture
(°
C)
1890 1920 1950 1980 2010
14
15
16
17
18
19
Boulia
Year
An
nu
al
min
imu
m t
emp
era
ture
(°
C)
1938 1962 1986 2010
13.5
14.0
14.5
15.0
15.5
16.0
Oodnadatta
Year
An
nu
al
min
imu
m t
emp
era
ture
(°
C)
1965 1980 1995 2010
14
15
16
17
Birdsville
Year
An
nu
al
min
imu
m t
emp
era
ture
(°
C)
P < 0.05
Max Temp
1885 1910 1935 1960 1985 2010
27
28
29
30
Alice Springs
Year
An
nu
al
ma
xim
um
tem
per
atu
re (
° C
)
1890 1910 1930 1950 1970 1990 2010
30
31
32
33
34
Boulia
Year
An
nu
al
ma
xim
um
tem
per
atu
re (
° C
)
1960 1970 1980 1990 2000 2010
29
30
31
32
Birdsville
Year
An
nu
al
ma
xim
um
tem
per
atu
re (
° C
)
1940 1950 1960 1970 1980 1990 2000 2010
27
28
29
30
31
Oodnadatta
Year
An
nu
al
ma
xim
um
tem
per
atu
re (
° C
)
P < 0.05
Rainfall
P < 0.05
1930 1950 1970 1990 2010
50
180
310
440
570
700
Bedourie
Year
An
nu
al
Ra
infa
ll (
mm
)
1890 1920 1950 1980 2010
50
180
310
440
570
700
Glenormiston
Year
An
nu
al
Ra
infa
ll (
mm
)
1905 1940 1975 2010
100
200
300
400
Oodnadatta
Year
An
nu
al
Ra
infa
ll (
mm
)
1870 1905 1940 1975 2010
200
400
600
800
Alice Springs
Year
An
nu
al
Ra
infa
ll (
mm
)
Extreme high eventsExtreme low eventsMedian events
Rainfall
Results: climate
• Decrease in years between extreme rainfall events (>95th quantile).
• GLMM estimate: -0.54, SE = 0.21, z value = -2.54, P = 0.01.
Methods: small mammals
• 22 years live-trapping data:
– rodents and dasyurids.
• Threshold relationship.
• Piecewise regression.
Results: small mammals
Rodents
Dasyurids
Summary• Extreme and median temperatures have
increased at both spatial scales.
• Magnitude of extreme rainfall events have increased, droughts getting drier, but variable across the region.
• Increased frequency of large rainfall events.
• Populations driven by extreme climate events.
Implications
• Increased wildfire.
• Establishment of introduced
species.
• Indirect effects and new
interactions.
• For more: Ecology and Evolution 2012; 2(11): 2645–2658.
Acknowledgements• Bobby Tamayo and the DERG team.• All our volunteers.• Bush Heritage Australia.• Bedourie Hotel.• ARC and APA.
Volunteer info at:http://sydney.edu.au/science/biology/sites/dickmanlab/index.shtml
