A view from above: changing seas, seabirds and food sources
Seabirds sit at the top of the marine food web and hence are sensitive to human activities, and changes in environmental and biological conditions which affect the whole ecosystem. There is growing evidence that the scale of impact of climate change on marine waters around the UK is becoming sufficiently pronounced to have a noticeable effect on seabird populations.
Climate change has already caused changes in plankton and fish distribution and species compositions and, compounded by fishing, is probably involved in a marked decline in the productivity of sandeel stocks around the UK. Sandeels are the key food source of most seabirds, and the decline in sandeel availability has led to a decrease in numbers and breeding success of several species of seabirds.
In the short term (less than 5 years), the recent succession of poor breeding years caused by sandeel availability are likely to propagate through the population leading to a decline in adult breeding numbers. Beyond this, changes will depend on the balance between breeding success, maturation rate and adult survival, which are difficult to predict. Much will depend on future patterns of sandeel production or whether an alternative prey species emerges which is available to seabirds.
What could happen next?
Continued warming in UK waters could mean that -
- Southern fish and plankton species will continue to increase in UK waters, and previously dominant cold water species will retreat northwards or into deeper water.
- Black-legged kittiwakes, terns and skuas continue to decline due to low production of sandeels.