the potential implications of climate change for the wheat-aphid-ydv pathosystem
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The potential implications of climate change for the wheat-aphid-YDV pathosystemTRANSCRIPT
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The potential implications of climate change for the wheat-
aphid-YDV pathosystem in WA: a simulation modelling study
Cooperative Research Centre for National Plant Biosecurity
Hazel Parry1,2, Darren Kriticos1,2, Jean-Philippe Aurambout3, Wendy Griffiths2,3, Garry O’Leary3, Kyla Finlay3, Piotr
Trębicki3, Paul De Barro1,2, Jo Luck2,3
1CSIRO Ecosystem Sciences 2Cooperative Research Centre for National Plant Biosecurity
3Department of Primary Industries Victoria
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Wheat-aphid-YDV pathosystem
R. padi BYDV
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CLIMATE CHANGE
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Large scale
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No risk Endangered (no change or change unknown) Transient (no change or change unknown) No risk (positive change from endangered or transient)
Climatic niche 2030 Rhopalosiphum padi
Kriticos DJ and Macfadyen S (in prep)
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Aphids-YDV-climate change
Shift in tropical agricultural zone
Warmer, drier summers Tropical agricultural zone Increased Ryegrass and wheat yield BYDV-RMV and R. maidis increase
Parry HR, Macfadyen S and Kriticos DJ (2012) Australasian Plant Pathology
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Small scale
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eCO2 and aphid fecundity Indirect impacts mediated through changes to host plant
For R. padi daily fecundity results from the project conflicted with the literature.
Xing et al. 2003.
Daily reproduction increased with eCO2 (350 vs 550 vs 700 ppm)
P. Trebici (CRC project results)
Daily reproduction decreased with eCO2 (350 vs 650 ppm)
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Wheat biomass under ambient and elevated CO2 and YDV (early) infection:
laboratory and field studies
eCO2 Field: 550 ppm eCO2 Lab: 650 ppm
Field Results
Laboratory Results
Elevated CO2 increases Biomass
Early YDV infection reduces Biomass
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Process-based, mechanistic models
Drivers
Temperature Precipitation CO2
Mechanisms
Survival Development Movement Fecundity
Outcomes
Population size and growth Age/size structure Extinction probability Emigrants
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Avondale case study
Avondale
Wokalup
1. Initiation in Irrigated Pasture 2. Wind Dispersal 3. Settling in Wheat
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0
1
2
3
4
5
6
0 100 200 300 400
1998 Phenostage2030 Phenostage2070 Phenostage
Avondale case study Te
mpe
ratu
re d
iffer
ence
°C
0
0.5
1
1.5
2
2.5
3
3.5
0 200 400
2030 relative to 1998
2070 relative to 1998
Day of year
Day of year
Whe
at p
heno
stag
e
1998 CO2 = 350 ppm 2030 CO2 = 450 ppm 2070 CO2 = 620 ppm
Climate Scenario CSIRO MK-3 A2 emissions
Wheat development accelerates with Climate Change
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Wheat impacts
Day of year
Bio
mas
s (k
g/ha
)
Biomass Yield
Day of year G
rain
har
vest
(kg/
ha)
0
1000
2000
3000
4000
5000
6000
7000
8000
0 100 200 300 400
1998 average biomass
2030 average biomass
0
1000
2000
3000
4000
5000
6000
0 100 200 300 400
1998 Grain2030 Grain2070 Grain 2070 average
biomass
Biomass and Yield decline with Climate Change
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Aphid impacts
Migrant arrivals Population dynamics
Aphid migration delayed Aphid population growth accelerates
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Consequences for wheat yield
Projected percentage loss in Grain Yield 2030 and 2070 compared to 1998 with and without YDV
Impact of YDV
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Consequences for YDV impact on wheat
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Summary: WA case study Climate change = more rapid crop development but lower
biomass and yield, most pronounced in 2070. Climate change is projected to:
- Slow aphid population growth over-summer in grasslands - Delay aphid timing of migration - Increase aphid population growth rate in crop, leading to - Earlier alate (winged morph) formation in crop, due to density
Synchronisation issues are more important to YDV impacts on yield than the within-crop aphid population growth.
Overall, our simulations suggest YDV impacts on yield will reduce under climate change, although the potential for spread in the crop is greater.