Impacts of climate change on seabirds
Francis Daunt and Ian Mitchell
Daunt, F. and Mitchell, I. (2013) Impacts of climate change on seabirds, MCCIP Science Review 2013, 125-133, doi:10.14465/2013.arc14.125-133
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What is already happening?
Seabird breeding populations in the UK increased in size over much of the last century, but since 1999 these populations have declined by an average of 7.5%. Breeding success has also declined over the same period. Some of the greatest reductions have occurred in the northern North Sea and Scottish Continental Shelf.
Climate change is considered to be one of the main drivers of these declines. Warmer winter sea temperatures have resulted in major changes in abundance and species composition of plankton in the North Sea that have contributed to the reduction in abundance and quality of seabird prey species such as sandeels, with knock-on effects for seabirds. Furthermore, there is growing evidence that breeding phenology is changing, with seabirds becoming increasingly de-synchronised from their prey. However, regional variations in the impacts of climate change are apparent, with weaker effects on seabird demography in the Irish Sea, Celtic Sea and English Channel.
What could happen?
Models predict that, by 2100, the UK climate will no longer be suitable for great skua and Arctic skua. The same models predict that the geographic range of black guillemot, common gull and Arctic tern will shrink so that only Shetland, Orkney and the most northerly tips of mainland Scotland will hold breeding colonies.
Further changes in prey abundance, species composition, energetic quality or synchronisation may have profound effects on seabirds. In addition, an increase in the frequency of extreme weather events could affect breeding habitat and create unfavourable foraging conditions, which may lead to increased mortality of adults and chicks.
Other drivers of seabird populations may interact with climate change. There is concern that climate change may increase the effects of disease and pollutants. Furthermore, impacts of collision and displacement from marine renewables may be exacerbated by reductions in prey quantity and quality as a result of climate change.