An entire species of Hawaiian bird has been reduced to 12 surviving members. Stuart Pimm knows them all individually.

"There were once upon a time about 150 species of birds in Hawaii," he said. "Of these, only about 10 survive in sufficient numbers that you can say they are not endangered or already extinct."

The internationally known ecologist has made a specialized investigation into extinction, focusing on the Hawaiian islands and the Amazon rainforests. "Species are going extinct, and they are going extinct at quite an alarming rate," he said. "Routinely we have destroyed one natural resource after another."

A species becoming extinct is by itself not remarkable, Pimm said. But the frequency of extinction has accelerated rapidly over the past few centuries. "We are losing species 100 times or 1,000 times faster than we were historically," he said. The reason to care is clear, he said. He cited for example a deadly poisonous coral that is found only near Hawaii. "A great deal of our drugs come from peculiar species like this," he said. "Sure, it can kill you, but a little less of it might kill that cancer growing inside you."

He cited the movie Medicine Man, starring Sean Connery as a scientist racing to find a cure for cancer ahead of the people razing the rainforest. That picture, Pimm said, is an accurate one. "The Amazon rainforest is a spectacular place, rich in species," he said. "This is where a lot of the biological richness of this planet is. And this is what we're chopping down. This is what we're destroying. How many species are we going to lose here?"

A colleague of Pimm's once discovered 40 new species of plant on a rainforest ridge, Pimm said. The day after that discovery, the ridge was razed. "It's hard to know what we've lost," he said. "If we'd lost the western yew tree, would we know we'd lost a cure for ovarian cancer?"

Another concern, he said, is the growing quantity of carbon dioxide in the atmosphere. "Most of the muck that we put into the atmosphere is taken out by the forests," he said. "It is a very effective cleaning system." As forests are destroyed, he said, less carbon dioxide is removed from the air.

In the United States, he said, "we have chopped up the once continuous forest and left little woodlets, little postage stamps of natural habitats."

The variety of life in the world should also be preserved for its own sake, Pimm said. "Diversity is worth something," he said. "It has a value over and above what we can get from it for drugs or genes or ecosystem servicing."

People who have never seen Prince William Sound felt loss when the area was devastated by an Exxon tanker oil spill, he said. "How much is a cheetah worth to you?" he asked. "If I told you if you didn't pay me I'd destroy all the cheetahs in the world, you'd pay me something, wouldn't you? ... There's a value there somewhere, and just because it's difficult to estimate doesn't mean it isn't there."

A zoology professor at the University of Tennessee, Pimm serves on committees of the National Academy of Science and the Scientific Advisory Board of the Center for Conservation Biology.

[ by Tom Knapp ]