Croak : Frogs send signal of extinction

Edit (Moderator): Moved from Human Interest to Wilderness, Wildlife and Ecology.

Link : http://www.startribune.com/stories/561/5043382.html

Up here at the top of the food chain, it's possible to overestimate humankind's accomplishments in environmental stewardship.

It's undeniable that much progress has been made, especially in the last 30 years or so: Auto exhaust is cleaner; industrial effluent no longer makes the rivers fire-prone; the skies are not so sooty; here and there, a species has been brought back from the brink of extinction. But is the planet in better shape, overall, than at any point in its past?

That's a large and complicated question, but most serious experts would say no. The major initiatives on pollution control, especially, have centered on the problems of greatest immediate concern to our own species -- but many others just aren't on the radar screen. As a case in point, consider last week's shocking report on the accelerating extinction of amphibians.

Science has classified about 5,700 different types of frogs, salamanders and other critters in this class, and has just completed its first detailed, worldwide population counts. The news is very bad: About 150 have gone extinct, and one-third of the remainder are at imminent risk of disappearing.

Of course, extinctions in all classes of plants and animals are occurring at alarming and accelerating rates, mostly because of human-caused changes in land use, air and water quality, global climate patterns and so on. But amphibians seem to be taking the biggest hit, perhaps primarily because of water pollution from pesticides and fertilizers.

This is significant for two reasons. First, the sensitivity of these creatures to waterborne toxins makes them equivalent to the coal miner's canary; their problems may signal what's in store for fish, birds and mammals. Second, the survival of so many amphibious species since dinosaur times suggests that they are unusually resilient in the face of natural environmental changes -- but not such factors as the gradual poisoning of ground water with agricultural chemicals, which has yet to get the serious and sustained attention it deserves.