Caspian Tern (Hydroprogne caspia): vulnerability to climate change
Evidence for exposure
Potential changes in breeding habitat suitability:
-
Current breeding area that is likely to become less suitable (97% of current range)
-
Current breeding area that is likely to remain suitable (3%)
-
Current breeding area that is likely to become more suitable (0%)
Current impacts to Caspian Terns attributed to climate change:
-
There are no impacts of climate change recorded for this species
Predicted changes in key prey species:
No key prey species are predicted to decline for this species.
Climate change impacts outside of Europe
-
Caspian terns in North America have been negatively affected by heatwaves, warming seas, severe storms, and increased frequency of flooding, all of which are linked to climate change.
Sensitivity
-
Caspian tern chicks are sensitive to heatwaves, and particularly hot summers in the US have resulted in mass mortality. Heatwaves are likely to become more frequent and extreme due to climate change, which will likely negatively impact Caspian terns.
-
Caspian terns are vulnerable to predation by American mink, which are increasing in part due to climate change. No effect on populations has been observed so far, but climate change may contribute to additional predation pressure.
-
Caspian terns in Europe typically nest on low-lying beaches, making them sensitive to flooding and tidal surges. Extreme weather events are projected to become more frequent in many areas, and therefore may lower tern breeding success
-
Caspian terns are primarily surface feeders. If climate change results in prolonged stormy weather, or extended heatwaves drive prey species into deeper water, then it would likely result in Arctic terns struggling to forage effectively.
-
Caspian terns typically only nest on rocky substrates with very little vegetation. Additional growth can cause them to abandon nesting sites. This is a particularly an issue in the Baltic due to high levels of nutrients on islands, and is likely to be exacerbated by climate change.
Adaptive capacity
-
Caspian terns are known to abandon and re-locate colonies following changes in environmental conditions or disturbance. This is likely to be adaptive in terms of climate change, as it seems highly likely terns will redistribute to more suitable areas if available.
