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<u>POCONO RECORD</u> (Stroudsburg, Pennsylvania) 25 June 06 Many amphibians losing war against extinction (John Serrao)
Over the past decade, amphibians have assumed the unenviable role as the group of animals experiencing the most dramatic decline in numbers. Fully a third of the world's 6,000 frog, toad and salamander species are now endangered or threatened with extinction. That's about 2,000 species that are in critical danger of disappearing from the earth forever.
Dozens have already become extinct in the past 20 years, some just a few years after having been present in incredible numbers, such as the famous golden toad of Costa Rica. And these lost frogs include some remarkably unique species like Australia's gastric brooding frog, the females of which actually swallow their eggs and later regurgitate the hatched tadpoles into the water! This species was only discovered about 20 years ago but hasn't been seen in a decade.
The most frightening aspect of these disappearances and declines is the global scope of this phenomenon. It's not restricted to any one part of the world, but rather has occurred on every continent and — most perplexing of all — especially in the most pristine, untouched wilderness areas. Frogs and toads, for example, have disappeared or dwindled down to tiny remnant populations in tropical forest preserves of Central and South America and in large national parks of the western United States.
These are places where scientists would least expect animals to suffer such mysterious declines, since their habitats are fully protected from disturbance.
At a recent lecture I attended during a Cornell University alumni reunion, Professor Kraig Adler reviewed the possible reasons for these alarming developments. These have all been published in various popular magazines and scientific journals over the past decade, but it was very instructive to hear them being explained by an expert who is actually working with these animals.
One possible reason is pollution which enters the aquatic habitats of amphibians and invades their bodies through their very permeable skins. The pollution can be in the form of pesticides, agricultural fertilizers, industrial chemicals or residential run-off. Indeed, various deformities extra legs in Midwestern frogs have been attributed to agricultural pollution. And acid rain the result of smokestack emissions combining with atmospheric moisture has poisoned many northern lakes and ponds, rendering them devoid of life.
Another possible cause is the destruction of the ozone layer which allows harmful ultraviolet light to penetrate. Research in the mountains of the western United States has found that amphibians and their eggs may be very sensitive to ultraviolet light, especially at high elevations where the air is thin.
Several endangered frogs have been found suffering from internal parasites or other infectious organisms. In particular, the chytrid fungus has been proven to be responsible for the deaths of many species of frogs throughout the world. Biologists have actually witnessed these frogs dying from the fungus in the wild and have described the process like a scene from a science-fiction movie — the frog seems to be moving around in a normal fashion and then suddenly "freezes" into its death pose.
It's been suggested that this fungus is being inadvertently spread across the globe's wilderness by attaching itself to scientific researchers and ecotourists. Recent research, however, has uncovered another explanation for this fungus' sudden, devastating effect on frogs — global warming. Studies have proven that the fungus has become much deadlier in environments where the climate has warmed up.
Adler concluded his lecture by assuring the audience that the local amphibians of Ithaca, N.Y., don't seem to be affected by any of the above factors. However, automobile traffic has taken a toll on amphibians as they cross roads during their annual spring migrations from the forests to breeding ponds. Special underpasses have been created along a Cornell wildlife preserve to allow the frogs and salamanders safe passage on the rainy spring nights when they travel, and this has decreased their mortality by 80 percent.
The situation here in the Poconos is the same as in Ithaca. Our amphibians have been spared the fatal consequences of pollution, acid rain, ultraviolet light, chytrid fungus and global warming, but they're being increasingly crushed beneath the wheels of cars as countless new roads are being built in the relentless process of transforming woodlands into housing developments, schools, malls and shopping centers.
A few years ago, Delaware Water Gap National Recreation Area initiated the annual closing of River Road during the first rainy spring evenings when amphibians by the thousands cross the road to enter the large wetland at the park headquarters. This has saved countless lives, but in light of the tremendous pace of development in the Poconos, it may be just a drop in the bucket.
http://www.poconorecord.com/apps/pbcs.dll/article?AID=/20060625/NEWS01/606250310
Over the past decade, amphibians have assumed the unenviable role as the group of animals experiencing the most dramatic decline in numbers. Fully a third of the world's 6,000 frog, toad and salamander species are now endangered or threatened with extinction. That's about 2,000 species that are in critical danger of disappearing from the earth forever.
Dozens have already become extinct in the past 20 years, some just a few years after having been present in incredible numbers, such as the famous golden toad of Costa Rica. And these lost frogs include some remarkably unique species like Australia's gastric brooding frog, the females of which actually swallow their eggs and later regurgitate the hatched tadpoles into the water! This species was only discovered about 20 years ago but hasn't been seen in a decade.
The most frightening aspect of these disappearances and declines is the global scope of this phenomenon. It's not restricted to any one part of the world, but rather has occurred on every continent and — most perplexing of all — especially in the most pristine, untouched wilderness areas. Frogs and toads, for example, have disappeared or dwindled down to tiny remnant populations in tropical forest preserves of Central and South America and in large national parks of the western United States.
These are places where scientists would least expect animals to suffer such mysterious declines, since their habitats are fully protected from disturbance.
At a recent lecture I attended during a Cornell University alumni reunion, Professor Kraig Adler reviewed the possible reasons for these alarming developments. These have all been published in various popular magazines and scientific journals over the past decade, but it was very instructive to hear them being explained by an expert who is actually working with these animals.
One possible reason is pollution which enters the aquatic habitats of amphibians and invades their bodies through their very permeable skins. The pollution can be in the form of pesticides, agricultural fertilizers, industrial chemicals or residential run-off. Indeed, various deformities extra legs in Midwestern frogs have been attributed to agricultural pollution. And acid rain the result of smokestack emissions combining with atmospheric moisture has poisoned many northern lakes and ponds, rendering them devoid of life.
Another possible cause is the destruction of the ozone layer which allows harmful ultraviolet light to penetrate. Research in the mountains of the western United States has found that amphibians and their eggs may be very sensitive to ultraviolet light, especially at high elevations where the air is thin.
Several endangered frogs have been found suffering from internal parasites or other infectious organisms. In particular, the chytrid fungus has been proven to be responsible for the deaths of many species of frogs throughout the world. Biologists have actually witnessed these frogs dying from the fungus in the wild and have described the process like a scene from a science-fiction movie — the frog seems to be moving around in a normal fashion and then suddenly "freezes" into its death pose.
It's been suggested that this fungus is being inadvertently spread across the globe's wilderness by attaching itself to scientific researchers and ecotourists. Recent research, however, has uncovered another explanation for this fungus' sudden, devastating effect on frogs — global warming. Studies have proven that the fungus has become much deadlier in environments where the climate has warmed up.
Adler concluded his lecture by assuring the audience that the local amphibians of Ithaca, N.Y., don't seem to be affected by any of the above factors. However, automobile traffic has taken a toll on amphibians as they cross roads during their annual spring migrations from the forests to breeding ponds. Special underpasses have been created along a Cornell wildlife preserve to allow the frogs and salamanders safe passage on the rainy spring nights when they travel, and this has decreased their mortality by 80 percent.
The situation here in the Poconos is the same as in Ithaca. Our amphibians have been spared the fatal consequences of pollution, acid rain, ultraviolet light, chytrid fungus and global warming, but they're being increasingly crushed beneath the wheels of cars as countless new roads are being built in the relentless process of transforming woodlands into housing developments, schools, malls and shopping centers.
A few years ago, Delaware Water Gap National Recreation Area initiated the annual closing of River Road during the first rainy spring evenings when amphibians by the thousands cross the road to enter the large wetland at the park headquarters. This has saved countless lives, but in light of the tremendous pace of development in the Poconos, it may be just a drop in the bucket.
http://www.poconorecord.com/apps/pbcs.dll/article?AID=/20060625/NEWS01/606250310
