Razorbill (Alca torda): 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 (80% of current range)
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Current breeding area that is likely to remain suitable (18%)
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Current breeding area that is likely to become more suitable (2%)
Current impacts to Razorbills attributed to climate change:
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Negative Impact: Extreme storms during the razorbill breeding season have led to wide-spread nest destruction, nesting failure and a net reduction in annual population production
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Negative Impact: Warmer temperatures correlate with lower adult razorbill mortality, most likely through changes in prey availability.
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Negative Impact: Warmer temperatures correlate with lower razorbill productivity, most likely through changes in prey availability. In addition, razorbill productivity has slowly declined over time, most likely due to changes in prey availability due to climate change
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Neutral Impact: Key prey species have shifted their life-cycle, likely in response to climate change, but razorbills have not adjusted in response. There is concern this could result in trophic mismatch, but no overall effect on breeding success has so far been observed.
Predicted changes in key prey species:
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Key prey species are likely to decline in abundance in the Baltic, the Irish Sea and the English Channel
Sensitivity
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Razorbills prefer to nest in exposed places, which makes nests particularly vulnerable to storms. Any increase in the frequency or intensity of storms during the breeding season is likely to have severe consequences on razorbill breeding success.
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Razorbills are prone to mass-mortality events (“wrecks”), both across Europe and in North America. The exact cause behind them is not certain, but likely related to food availability and winter storms. This makes drastic populations reductions more likely, as well as result in long recovery periods.
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Many razorbill populations are heavily reliant on a few prey species, especially during the breeding period. Any change in prey availability, particularly sandeels, is likely to have consequences for razorbill populations.
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Razorbills are vulnerable to mammal predation, and the spread of introduced mammals (made possible due to climate change) could threaten more northern populations than previously.
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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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Razorbills are pelagic and are easily capable of reaching new potential colony sites. In North America there is some evidence they will colonise new areas to match key prey species ranges. However, there is no observed example of this occurring in Europe.
