Post by calabi-yau on Oct 15, 2004 13:37:18 GMT -5
Rove to Bush: " No sir, Chirac is well. It's about the other kind. The kind you like to watch explode when you smoke'em up, sir."
Farewell to the frog?
Alok Jha, science correspondent
Friday October 15, 2004
The Guardian
A third of the world's amphibian species are in danger of extinction, according to the first ever global survey of the animals. Scientists think that the mysterious collapse in numbers might be a warning that our environment may be in a worse state than we think - amphibians are known to be the most sensitive of all animals to subtle changes in their ecosystems.
There is also a new spectre that has come to haunt the frogs, toads, salamanders and newts that live in and out of water - a fungus that has already destroyed entire populations in many parts of the world and could spread to Britain.
Scientists have known since the 1980s that the many of the world's amphibian species are vanishing but the scale of decline revealed by the new survey, published today in Science, has stunned them. Nobody knows what is causing the devastation but it is likely to be loss of habitat to pollution, climate change and increasing competition with humans.
More than 500 scientists from more than 60 countries took part in the three-year Global Amphibian Assessment, a study of the world's 5,743 known amphibian species. One in three - a total of 1,856 species altogether - are threatened with extinction, they say. The latest count shows 122 amphibian species have become extinct in the past 20 years.
At the global level, scientists say that the drop in amphibian numbers could be an indicator of the poor state of our environment. "Amphibians feel the effects of water pollution, climate change before other forms of life including mankind," said Neil Cox, a programme officer with the joint World Conservation Union and Conservation International biodiversity assessment unit, which coordinated the survey. "They are the best indicators overall of environmental health largely because their porous skins allow for water transpiration and movement of chemicals."
But damage to the environmental is not the whole story. Many species have disappeared from pristine habitats that have suffered little environmental damage. "This is thought to be a response partly to outbreak of the disease chytridiomycosis," said Mr Cox.
The disease is caused by a fungus of the chytrid family called Batrachochytrium dendrobatidis and it infests the skin of adult amphibians and the mouth-parts of their larvae. "Amphibians drink through their skin and they also breathe through their skin, so anything that happens to their skin really screws them up," said Dr Matthew Fisher, a molecular epidemiologist at Imperial College London. "Tadpoles carry it but they're absolutely healthy. It's when they metamorph into little froglets that they die instantly - as soon as they hop out of the pond."
There is no practical treatment for the disease, which is concentrated mainly in Australia, North and Central America and the Caribbean, and it is spreading. The fungus has been implicated in the extinction of the Kihansi spray toad from Tanzania and, in Europe, it has been found infesting the common midwife toad.
There have been no confirmed cases of the disease in Britain, but it could be just a matter of time.
Farewell to the frog?
Alok Jha, science correspondent
Friday October 15, 2004
The Guardian
A third of the world's amphibian species are in danger of extinction, according to the first ever global survey of the animals. Scientists think that the mysterious collapse in numbers might be a warning that our environment may be in a worse state than we think - amphibians are known to be the most sensitive of all animals to subtle changes in their ecosystems.
There is also a new spectre that has come to haunt the frogs, toads, salamanders and newts that live in and out of water - a fungus that has already destroyed entire populations in many parts of the world and could spread to Britain.
Scientists have known since the 1980s that the many of the world's amphibian species are vanishing but the scale of decline revealed by the new survey, published today in Science, has stunned them. Nobody knows what is causing the devastation but it is likely to be loss of habitat to pollution, climate change and increasing competition with humans.
More than 500 scientists from more than 60 countries took part in the three-year Global Amphibian Assessment, a study of the world's 5,743 known amphibian species. One in three - a total of 1,856 species altogether - are threatened with extinction, they say. The latest count shows 122 amphibian species have become extinct in the past 20 years.
At the global level, scientists say that the drop in amphibian numbers could be an indicator of the poor state of our environment. "Amphibians feel the effects of water pollution, climate change before other forms of life including mankind," said Neil Cox, a programme officer with the joint World Conservation Union and Conservation International biodiversity assessment unit, which coordinated the survey. "They are the best indicators overall of environmental health largely because their porous skins allow for water transpiration and movement of chemicals."
But damage to the environmental is not the whole story. Many species have disappeared from pristine habitats that have suffered little environmental damage. "This is thought to be a response partly to outbreak of the disease chytridiomycosis," said Mr Cox.
The disease is caused by a fungus of the chytrid family called Batrachochytrium dendrobatidis and it infests the skin of adult amphibians and the mouth-parts of their larvae. "Amphibians drink through their skin and they also breathe through their skin, so anything that happens to their skin really screws them up," said Dr Matthew Fisher, a molecular epidemiologist at Imperial College London. "Tadpoles carry it but they're absolutely healthy. It's when they metamorph into little froglets that they die instantly - as soon as they hop out of the pond."
There is no practical treatment for the disease, which is concentrated mainly in Australia, North and Central America and the Caribbean, and it is spreading. The fungus has been implicated in the extinction of the Kihansi spray toad from Tanzania and, in Europe, it has been found infesting the common midwife toad.
There have been no confirmed cases of the disease in Britain, but it could be just a matter of time.