Amphibian Armageddon

The most frightening news of the past week -- worse than the continuing calamity in Iraq, the lousy economic prognosis or the fact that millions of Americans still plan to vote for George W. Bush -- was the release of a study concluding that almost one-third of all known amphibian species worldwide are "threatened," i.e., going extinct rapidly or going extinct a little more slowly. They're all about to croak! Something in the environment has gone horribly wrong, and we have only the beginnings of guesses as to what it could be.

This is the kind of announcement that, if we had a decent government, would be met with a slightly panicky but resolute determination to get to the bottom of the problem and do what is still possible to reverse the decline. Too bad it's also the kind of announcement that elicits nothing more than a dismissive snort from the current administration. "Toads?! Ooh -- eye of newt!" Of course, biologists have been issuing warnings about amphibians' mysterious difficulties for 10-15 years but have never gotten any traction in Washington.

When most people think of the biosphere -- if they think of it at all -- they probably picture it as a sort of gigantic mosaic, with each species of animal, plant or microorganism represented by a single tile in an array of millions. If a species goes extinct, it just leaves a tiny hole. Even if a large group of species disappears, the only problem is an empty patch that's still relatively small compared to the picture as a whole. The mosaic still "works."

The terrible flaw in the mosaic metaphor, obviously, is that its simplistic representation of life fails to convey the huge degree of interconnectedness of species, and the chaotic nature of the biosphere. At some point, removing a species or a group of species does more than leave an unsightly but tolerable vacancy -- it causes many other neighboring species and groups of species to come tumbling down in a cascade of death and disaster. And we have no idea what that point is. The next salamander squished could be the salamander that breaks the biosphere's back, and takes us along with it.