Seas of plenty? But only for some
This year's seabird breeding season across the UK served up a mixed bag of the good, the bad and the all-time low, according to monitoring on RSPB's coastal reserves. While some colonies saw their best season for years, the far north experienced an abysmal summer, with sensitive species such as Kittiwake and terns abandoning chicks, failing to nest and, in some cases, not returning to nesting sites at all.
On the Shetland island of Mousa, the 700 Arctic Terns present at the start of the breeding season failed to produce a single chick. On Orkney, the situation was similarly miserable for this species: on RSPB's North Hill reserve, only 356 Arctic Tern pairs returned to a site that held over 3,000 pairs in the early 1990s. Just two Kittiwakes returned to North Hill to breed, and not a single chick fledged there. A comprehensive survey of Great Skuas on Orkney shows that nearly a quarter of the pairs present at the beginning of the decade have disappeared — a decline on Orkney that represents 3% of the global population of this species.
It appears that climate change has had a significant role to play in these declines. The Sir Alistair Hardy Foundation for Ocean Science (SAHFOS) has discovered a massive 70% decline in the total biomass of copepod plankton in the northeast Atlantic since the 1960s, associated with an increase in sea surface temperatures. In addition, the colder-water species Calanus finmarchicus, once the predominant copepod species, has now been replaced by Calanus helgolandicus, a warmer-water species, as the dominant species in the northeast Atlantic. It appears that this has negatively affected sandeel populations, which in turn has impacted sandeel-reliant seabirds at the top of the marine food web. The full SAHFOS Eco Status report is available online.
Yet this is not the whole story. Some species continue to do well — Gannets, which have a huge foraging range and can tackle a wide variety of fish species, had another good season across the UK, with the colony at Bempton Cliffs expanding to more than 8,000 pairs. Some of RSPB's Welsh reserves had their highest numbers of Arctic and Common Tern for several years.
Doug Gilbert, Reserves Ecologist for RSPB, said: "Although 2010 has been a patchy year for seabird breeding, the terrible season for the critical colonies in the far north warns us that seabird populations in the UK remain in real danger. This is against a backdrop of long-term decline for many species. Such declines are an indictment of our stewardship of the marine environment."
Research carried out by RSPB indicates the value of seabirds goes beyond the ecological. The report The Local Value of Seabirds indicates that seabirds have significant and directly attributable monetary worth in rural areas. At RSPB's Bempton Cliffs reserve in Yorkshire, this figure was estimated to be over £750,000 in 2009, and at the Mull of Galloway RSPB reserve in Dumfries and Galloway the figure was over £125,000 in 2008.
"Anyone that has witnessed the cacophony of sound and activity that is a seabird colony in the breeding season knows that this is one of nature's great spectacles," said Rory Crawford, seabird policy officer for RSPB. "However, this report indicates that seabirds have an important economic value to local communities beyond their intrinsic and ecological value. This should be yet further incentive to ensure we properly protect our important populations in the face of significant impacts from climatic change. The tools — such as the establishment of marine protected areas — are available. It is crucial now that they are used to increase the resilience of our seabird populations in the face of large-scale environmental change."
The report The Local Value of Seabirds: Estimating Spending by Visitors to RSPB Coastal Reserves and associated Local Economic Impact attributable to Seabirds is available from the RSPB website.
Seabird Population Trends and Causes of Change: 2010 Report, published by JNCC in August, indicates that several species have declined between 1999 and 2009, notably Fulmar (38% decline), Arctic Skua (33% decline), Kittiwake (40% decline) and Herring Gull (43% decline). Individual species accounts and figures are available online.
The full SAHFOS Eco Status report available online.