King Eider (Somateria spectabilis): vulnerability to climate change
Evidence for exposure
Potential changes in breeding habitat suitability:
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Current breeding area that is likely to become less suitable (100% of current range)
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Current breeding area that is likely to remain suitable (0%)
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Current breeding area that is likely to become more suitable (0%)
Current impacts to King Eiders attributed to climate change:
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No impacts have been documented for this species in Europe
Predicted changes in key prey species:
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Key prey species are likely to decline in abundance on the west coast of Svalbard and around the Kanin Peninsula and the south Barents Sea
Climate change impacts outside of Europe
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Increase in ice break-up, and increased variability of break-up, caused by climate change has resulted in significant damage to benthic prey and has caused local shifts in prey availability. Currently this has only a small impact on King Eiders, but impacts could become significant in the future.
Sensitivity
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Eiders have shown declines during historical regime shifts in marine ecosystems, they are likely sensitive to future changes in marine regimes.
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Wetlands provide important breeding grounds for this species, and remote sensing and imaging has shown fluctuations in lakes in Siberia, with many lakes disappearing and others appearing. The impact on populations is unknown, as the area is difficult to study but the potential impact is very large.
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King eiders heavily rely on specific mollusc communities (e.g. Mytilus sp.), especially during the non-breeding season. Many marine mollusc species are known to be sensitive to climate change, and warmer conditions are likely to result in reduction of key prey species.
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King eiders tend to winter in large groups in relatively small areas, so are vulnerable to mass mortality through extreme events. Even localised climate change impacts may have large consequences on the population as a whole.
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King eiders are vulnerable to mass mortality, particularly during migration. Hundreds of thousands of individuals have been recorded dying following unexpected re-freezing of sea-ice. Change or variability of conditions during migration period could have significant impacts on the population.
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King eiders may be sensitive to the loss of sea ice, as it provides important roosting sites during winter and supports marine algae and benthic invertebrate prey. While impacts of the loss of sea ice have not been observed on eiders so far, it is a potential future impact.
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This species has a long generation length (>10 years), which may slow recovery from severe impacts and increases population extinction risk
Adaptive capacity
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Very low site fidelity to breeding areas (especially in males), but also few documented examples of breeding in novel areas, and no documented records of permanent colonisation. Overall it seems unlikely this species will range shift rapidly in response to climate change. High site fidelity to wintering areas, and even local changes to these sites may have significant impact on populations
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King eiders have varied migration pathways and strategies which vary between individual and between years. This plasticity likely provides some resilience to climate change, as eiders could change their migration strategy in response to local conditions.
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King eiders have low migration connectivity (populations will mingle during non-breeding season), and a weak genetic structure. This may be advantageous in response to climate change, as local adaptation is low and migration plasticity is high in king eiders which may allow them to respond rapidly to change.
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Eiders either abandon or skip breeding in particularly unsuitable years, preserving resources. This could be adaptive if conditions become more variable and ameliorate the impact of poor breeding conditions
