MAPPING ANIMAL FITNESS ONTO SEASONAL CLIMATE CHANGE F. Stephen Dobson Department of Biological...
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Transcript of MAPPING ANIMAL FITNESS ONTO SEASONAL CLIMATE CHANGE F. Stephen Dobson Department of Biological...
MAPPING ANIMAL FITNESS
ONTO SEASONAL CLIMATE CHANGE
F. Stephen Dobson
Department of Biological Sciences
College of Science & Mathematics
• GENERAL TOPIC: PHENOLOGICAL RESPONSES TO CLIMATE CHANGE
• GENERAL PATTERN: earlier dates of spring phenology with warming - including species at different trophic levels in the same habitats
• PROBLEM: because trophic links are involved, there may be mismatches between resources & reproduction for some of the species
specifically, breeding and peak resource periods may not match up
e.g., peak insect abundances and nestling feeding by breeding birdsoften coincide
Evidence of trophicinteractions
Typical story of timingacross trophic levels
1985 - 2005
This study compared
plant growthinsect development4 species - song birdsan avian predator
Both et al. 2009, JAE
Budburst
Caterpillars
Sparrowhawks
• GENERAL TOPIC: PHENOLOGICAL RESPONSES TO CLIMATE CHANGE
• SPECIFIC QUESTION: how much of the changes in timing is due to:
• Plastic responses of phenotypes• Genetic adaptations to new conditions
Breeding Date
cool warm
Spring temperature
A
B
Pattern:
Laying date is a week later than 20 years ago (b = 0.35 ± 0.05, p < 0.0001)[due to lower fish food abundance]
Heritability = h2 = 0.36 (± 0.05)
Selection gradient = S = -0.10
Breeder’s equation: R = h2 S
Conclusion 1: •natural selection favors earlier breeding, not later breeding!
Conclusion 2:
•later breeding due to phenotypic plasticity
Lower fitness with later emergence
OVER 20 YEARS:
•Emergence 9.4 days later
Heritability = h2 = 0.23 (± 0.05)
Selection gradient = S = -0.14
Breeder’s equation: R = h2 S
Conclusion 1: •natural selection favors earlier, not later emergence from hibernation!
Conclusion 2:
•later emergence due to phenotypic plasticity
Population grew, then declined
Δ Fitness & Δ Climate:
Summer temperature has gone up:
+4.4°C, mean = 16.5°C
Summer rainfall has gone down:
-3.7mm, mean = 2.5mm
Fitness has gone down:
r = -0.428 (P = 0.05), with temp
r = 0.548 (P = 0.01), with rain
AnnualFitness
AprilSnowfallbefore
July Rain &Temperature
Nov – DecSnowfall
DecemberSnowpack
0.046
0.468*
0.047
-0.032
AprilSnowfall
after
-0.223