Early ice retreat has opposite effects on planktivorous and piscivorous toppredators

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Early ice retreat has opposite effects on
planktivorous and piscivorous top-predators

• Alexander Kitaysky, Evgenia Kitaiskaia, Morgan
  Benowitz-Fredericks, Michael Shultz
• Institute of Arctic Biology
• University of Alaska Fairbanks

FUNDING AGENCIES NPRB, NPMR, EVOS, NSF,
EPSCoR, IAB
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• OUTLINE
• Responses of Planktivorous Piscivorous birds to
  timing of winter ice-retreat
• -reproduction (Sea of Okhotsk shelf,
  1987-current)
• -nutritional stress (Bering Sea shelf,
  1999-current)
• Inter-annual and Seasonal dynamics of food
  availability / nutritional stress

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Effect of climate variability on Food
Reproduction of piscivorous and planktivorous
seabirds
Sea of Okhotsk Talan Island 1987-current Kitaysky
Golubova 2000, in prep.
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Dates of winter ice retreat
WARM PHASE
COLD PHASE
Sea of Okhotsk Talan Island 1987-current Kitaysky
Golubova 2000
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Distribution of adult euphausiids Thysanoessa
rashii (major prey of planktivorous auklets)
COLD regime
WARM regime
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Distribution of Acartia and small copepods (major
prey of small forage fish)
COLD regime
WARM regime
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Kitaysky Golubova 2000 in prep
1987-current
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Conclusions for part 1 Timing of ice retreat
affects trophic level linkages in the northern
Sea of Okhotsk.Opposite responses of
planktivorous and piscivorous birds to the timing
of winter ice retreat were observed during
1987-2005Is it a common phenomenon in shelf
ecosystems with winter ice cover? Does it occur
in the Bering Sea? REFeR-Phase II
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Effects of climate variability on different
trophic levels (1999-2005, Bering Sea shelf
ecosystems)


Timing of ice retreat affects planktivorous
and piscivorous seabirds in opposite ways
(1986-2004)

shelf


need a method that allows sampling at large
geographic scale
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Environmental change . climate .
human-induced
General idea
Nutritional stress
Food availability
Population processes . reproduction . survival
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How to measure stress?
Energyneeds gt intake
Nutritional stress

Release of glucocorticoids. corticosterone
(CORT) in birds
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Method
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VALIDATION OF MONITORING TECHNIQUE
Secretion of stress hormones increases in
response to nutritional deficits
Kitaysky et al. 1999, 00, 01, 03, 05
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Secretion of stress hormones tracks changes in
food abundance colony, stage
NS food abundance plt0.001
R2.51
R2.56
Kitaysky, Piatt Wingfield. MEPS, in press
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How do we compare levels of stress among species?
MAX is called STRESS INDEX used for
comparisons among species
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Effects of climate variability on different
trophic levels (1999-2005, Bering Sea shelf
ecosystems)



shelf

?

RESULTS INTER-ANNUAL COMPARISONS Piscivorous
Common Thick-billed murres Planktivorous
Least Crested auklets
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EARLY ICE RETREAT LOWER STRESS IN PISCIVOROUS
COMMON MURRES
Nutritional STRESS index ( maximum)
1999
2002
2003
2004
2000
2005
Ice retreat index (days after March 15 source -
NOAA)
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EARLY ICE RETREAT LOWER STRESS IN PISCIVOROUS
MURRES
1999
2002
2003
2004
2000
2005
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EARLY ICE RETREAT HIGHER STRESS IN
PLANKTIVOROUS LEAST AUKLETS
1999
2002
2003
2004
2000
2005
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EARLY ICE RETREAT HIGHER STRESS IN
PLANKTIVOROUS AUKLETS
1999
2002
2003
2004
2000
2005
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OPPOSITE EFFECTS OF EARLY ICE RETREAT ON
PLANKTIVORES AND PISCIVORES
1999
2002
2003
2004
2000
2005
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Effects of climate variability on different
trophic levels (1999-2005, Bering Sea shelf
ecosystems)



shelf


St. Paul I.
RESULTS SEASONAL DYNAMICS OF FOOD i.e. LEAST
AUKLETS BREEDING ON St. PAUL I.
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SUMMARY OPPOSITE
EFFECTS OF EARLY ICE RETREAT ONPLANKTIVOROUS AND
PISCIVOROUS PREDATORSIS A COMMON PHENOMENON IN
THE SUB-ARCTIC IS IT A RESULT OF ON-GOING
CLIMATE CHANGE? IN ORDER TO PREDICT RESPONSES
OF TOP-PREDATORS TO CLIMATE CHANGE, WE NEED TO
UNDERSTAND CAUSAL MECHANISM(S) OF THIS
PHENOMENON PHYSICS LOW TROPHIC LEVELS
SEABIRDS ANSWER
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• Thanks to
• J.F. Piatt, G. Hunt, A. Springer, S. Iverson, A.
  Andreev, J. Wingfield, V. Byrd and all the
  Russian and American colleagues and students who
  contributed to development of ideas, supported,
  and participated in this ongoing project
• Funding
• NPRB
• EVOS
• USFWS
• NSF EPSCoR
• Institute of Biological Problems (Magadan,
  Russia)
• Zoology Department, University of Washington
• Institute of Arctic Biology, UAF

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Baseline and acute stress-induced concentrations
of CORT
acute stress-induced
baseline
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Acute stress-induced concentrations of CORT
indicate recent nutritional history
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Talan I. 1987-2004
Arctic Oscillation Index Seabird reproduction
PISCIVOROUS versus PLANKTIVOROUS