Thursday, January 18, 2007

Going, Going... Exotic Species are Decimating America's Native Wildlife

Biologists are noticing, however, and seven out of 10 say we are in the midst of a "mass extinction" of living things, according to a 1998 survey of 400 biologists commissioned by New York's American Museum of Natural History. One in eight known bird species around the world face a high risk of extinction in the near future, according to the authoritative 2000 International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species. That means entire species of birds face the same odds of disappearing from the planet for good as a woman in the U.S. does of developing breast cancer sometime in her lifetime. Mammals have it worse: One in four known mammals worldwide face a high risk of extinction in the near future.
Not since dinosaurs vanished 65 million years ago have so many species disappeared so quickly. And this time, it's mainly due to human activity and not natural phenomena like a comet smashing into the planet, say the polled biologists. They consider biodiversity loss a more serious environmental problem than global warming, pollution or depletion of the ozone layer. In the world's 4.5 billion years, there have been five mass extinctions. The sixth -- and fastest -- is under way, say biologists.

It may seem like no big deal to lose Florida's humble Ponce de Leon beach mouse, which has vanished due to "real estate development, and perhaps predation by domestic cats," as the IUCN Red List put it. But these very factors -- habitat loss and introduction of exotic species -- are among the main causes of our current global extinction crisis, biologists say.

"Many wonderful creatures will be lost in the first few decades of the 21st century unless we greatly increase levels of support, involvement and commitment to conservation," says Russell A. Mittermeier, president of Conservation International. Though most of those species live in more biologically diverse regions near the equator, the fact remains that about 280 out of 808 known extinctions have occurred in the U.S., WWF's Morrison points out.
And 42 percent of the nation's threatened or endangered species -- both animals and plants -- face trouble primarily because of competition with and being killed by non-native species, according to a 1999 Cornell University report. The report's lead author, David Pimentel, says he has found no reason for optimism since 1999. "More foreign species arrive each year," says Pimentel, professor of insect ecology and agricultural sciences. "I do not believe that we are winning the war on exotic species because of increased trade, increased number of people traveling, and the growing human population in the U.S. and world."

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