Biology, asked by dharavathpavankalyan, 8 months ago

which is considerd as gaint ecosystem

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Answered by khushroomirza7
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Explanation:

A giant ecosystem that has functioned for millions of years has begun to break down. They are disaster zones: professional ornithologists who have spent their careers monitoring the teeming, screaming bird life of Orkney and Shetland have never seen anything like it.

Answered by rohitsharma2k613
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Answer:

They are disaster zones: professional ornithologists who have spent their careers monitoring the teeming, screaming bird life of Orkney and Shetland have never seen anything like it.

They are disaster zones: professional ornithologists who have spent their careers monitoring the teeming, screaming bird life of Orkney and Shetland have never seen anything like it.

On cliff ledges, on moorlands, on shingle banks, the nesting attempts of hundreds of thousands of seabirds in Scotland's Northern Isles have come to grief in the summer of 2004.

It is the year without young. Eggs have not been laid; where eggs have been laid, they have not hatched; where they have hatched, the chicks have died in the nest, and the tiny numbers of chicks that have left the nest have not lasted long.

A giant ecosystem that has functioned for millions of years has broken down. The reason is starvation, and the reason for the starvation is thought to be climate change: this is a taste of things to come.

There have been seabird nesting failures in the Northern Isles before, but the extent of this year's catastrophe is entirely unprecedented.

On the island of Papa Westray in Orkney, for example, only five of the 85 nests of kittiwakes had chicks earlier this month. On the island of Foula, which has the world's largest colony of great skuas, scientists checking a representative sample of 400 nest sites found just two chicks, which were thought unlikely to survive.

At a cliff near Sumburgh Head on Shetland's southern tip, where 1,200 pairs of guillemots assembled to breed in the spring, not a single chick has been produced.

Arctic terns, of which the last census in 2000 recorded 24,716 breeding pairs in Shetland, have produced no chicks at all in the south of the islands, according to Peter Ellis, the local representative of the Royal Society for the Protection of Birds. "In the whole of Shetland they have produced just a handful," he said.

The story has been repeated right across both archipelagos and has a brutally simple immediate cause: starvation. The once-teeming stocks of sandeels, the small fish on which nearly all the local seabirds depend, have vanished, leaving the parent birds unable to feed their young - or even themselves. But behind the sandeels' disappearance is a more sinister cause, threatening us all as well as the seabirds: global warming.

Scientists believe the steadily rising temperature of the water in the North Sea, which has gone up by two degrees centigrade in 20 years, is having a calamitous effect on the sandeels, essentially a cold-water species. After several years of decline, they have vanished almost completely in the waters around Orkney and Shetland.

There is nowhere else in Britain where seabirds are so much part of the landscape, and the economy. The abundance of gulls, terns, skuas, guillemots and puffins has long been a prime tourist attraction, as well as of global wildlife significance. Shetland alone is thought to house 10 per cent of our eight million seabirds, and birders are the principal visitors heading for the treeless, windswept islands to see species they could not find elsewhere in Britain. Suddenly, all this is at risk.

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