20 March 2004	Saturday	28 Muharram 1425

LONDON: Scientists have produced the first comprehensive evidence that the diversity of butterflies, birds and plants is in decline in the UK. They say their research supports the argument that mass extinction threatens life on Earth.

In the past 20 years, according to a study in the US journal Science on Friday, about 70 per cent of all butterfly species in Britain have shown signs of decline. About 28 per cent of plant species and 54 per cent of bird species also declined in areas studied over long periods. The finding comes from government-funded scientists using data painstakingly amassed over the past 40 years by 20,000 skilled naturalists.

Sandra Knapp, a botanist at the Natural History Museum, London, England, said the UK survey gave a crucial message for the world: "The lesson and the warning are there for all to see. Britain, by virtue of its well-known and well-studied biodiversity, is the canary for the rest of the globe.

"This adds enormous strength to the hypothesis that the world is approaching its sixth major extinction event," said Jeremy Thomas of the UK's Natural Environment Research Council, who led the study of butterfly populations.

"The others appear to have been cosmic events, either from outer space coming in or some major perturbation - volcanoes, whatever - within the Earth. So they are believed to be physical events.

"You could say this latest one is an organic event: that one form of life has become so dominant on Earth that through its over- exploitation and its wastes, it eats, destroys, or poisons the others."

There have been five episodes of mass extinction in the last 500m years. The Ordovician period ended about 439m years ago with the loss of an estimated 84 per cent of species.

In the Late Devonian about 367 million years ago, 79 per cent of life was wiped out. At the close of the Permian period some 245 million years ago, 95 per cent of species disappeared in a cataclysmic event. -Dawn/The Guardian News Service.