THE most important seabird sanctuary in the Atlantic may be in unstoppable decline as climate change disrupts the marine food chain, conservationists fear.
The St Kilda archipelago became an internationally-important wildlife haven after the last human inhabitants left in 1930.
It has been in the care of the National Trust for Scotland (NTS) since 1957 and was made a Unesco World Heritage Site in recognition of its exceptional beauty and the significant natural habitats.
A major seabird breeding station and home to the world’s largest colony of gannets and the biggest flock of fulmars in the British Isles, St Kilda’s future is now thought to be under threat due to changes in the marine environment.
Communities of plankton, which forms the bedrock of the marine food chain, have shifted north by 620 miles in the past 30 years, destabilising the natural network the birds rely upon for their diet.
The decline began around the time Unesco status was conferred. NTS blames climate change and says kittiwakes may now be at risk of collapse.
Just one kittiwake nest was discovered across seven sites this season, with the sole chick hatched later dying. Meanwhile, after a century of growth, populations of puffins, fulmars, guillemots and razorbills are also “rapidly falling”.
Dr Richard Luxmoore, NTS senior nature conservation adviser, said: “Seabirds are essentially part of the marine ecosystem. Although they breed on land they spend most of their life out at sea and they can tell us a lot about its health.
“In the last 30 years plankton communities have shifted northward by 1,000 kilometres, more than the distance from Edinburgh to Paris, and it’s having huge impact.
“If vegetation shifted by a similar distance there would be pandemonium, but because it’s happening in the sea we tend not to notice.”
Seabirds were an important source of both food and supplies for the remote community, which survived through farming in harsh conditions.
At one time bird colonies were so abundant it was thought that each St Kildan resident ate 115 fulmars every year, with 89,600 puffins said to have been used for food and feathers in 1876 alone.
Luxmoore went on: “The message that seabirds are bringing back to us about the marine ecosystem is extremely worrying.
“We used to think that the tiny organisms in plankton were quite immune to climate change.
“But their shift in range combines with decreased abundance of up to 70 per cent, so it’s not surprising that the seabirds that depend on this are being left high and dry.
“If the inhabitants of St Kilda were to come back now nearly 90 years after their evacuation and see the cliffs that were once teeming with seabirds now almost empty, they would be horrified to see what has happened on the island where they once lived.”
The “significant decline” of most species on the archipelago is highlighted in a new film by NTS, titled St Kilda – Facing the Change, available on Vimeo.
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