In this issue of the [The New Yorker] magazine, Elizabeth Kolbert writes about the history of mass extinctions. Here Kolbert talks about the often indirect ways that human settlement has led to the demise of other species, and describes her visits to a frog preserve in Central America and a bat cave in the Northeast. To listen to this story Click here.
ABSTRACT: A REPORTER AT LARGE about the sixth mass extinction. Describes how graduate student Karen Lips observed the mysterious disappearance of large numbers of local golden frogs, in the nineteen-nineties, at several locations in Panama and Costa Rica. Whatever was killing Lips’s frogs moved east, like a wave, across Panama. Of the many species that have existed on earth, more than ninety-nine per cent have disappeared.
Yet extinction has been a much contested concept. Throughout the eighteenth century, the prevailing view was that species were fixed. Charles Darwin believed extinction happened only slowly, but he was wrong.
Over the past half billion years, there have been at least twenty mass extinctions. Five of these—the so-called Big Five—were so devastating that they’re usually put in their own category. The fifth, the end-Cretaceous event, which occurred sixty-five million years ago, exterminated not just the dinosaurs but seventy-five per cent of all species on earth.
Once a mass extinction occurs, it takes millions of years for life to recover, and when it does it’s generally with a new cast of characters. In this way, mass extinctions have played a determining role in evolution’s course.
It’s now generally agreed among biologists that another mass extinction is under way. If current trends continue, by the end of this century as many as half of earth’s species will be gone.
The writer went frog collecting in Chagres National Park with Edgardo Griffith, the director of EVACC (the El Valle Amphibian Conservation Center).
About two decades ago, researchers first noticed something odd was happening to amphibians. It’s difficult to say when the current extinction event—sometimes called the sixth extinction— began. Its opening phase appears to have started about fifty thousand years ago, when the first humans migrated across Australia and America. The main culprit in the wavelike series of amphibian crashes is a chytrid fungus, known as Bd. At this point, Bd appears to be unstoppable.
In 2007, biologist Al Hicks, of the New York State D.E.C., and the National Wildlife Health Center started investigating a series of mysterious bat deaths. Many of the dead bats were discovered with a white substance on their nose, which was cultured and found to be an unidentified fungus. Mentions White-Nose Syndrome (W.N.S.).
The writer visited an abandoned mine to study bats with Hicks.
One of the puzzles of mass extinction is why, at certain junctures, the resourcefulness of life seems to falter. Just in the last century, carbon dioxide levels in the atmosphere have changed by as much as they normally do in a hundred-thousand-year glacial cycle. In the end, the most deadly aspect of human activity may simply be the pace itself.