25% of Wild Mammal Species Face Extinction

Not all of the news was grim yesterday: IUCN officials said that the La Palma giant lizard, believed to be extinct for 500 years, was rediscovered last year in the Canary Islands and is now considered critically endangered.

The writers of the mammals assessment said the observed declines are not inevitable. "At least 5 percent of currently threatened species have stable or increasing populations," they wrote, "which indicates that they are recovering from past threats."

Said Mittermeier: "It comes down to protecting habitats effectively, through protected areas, and preventing hunting and other forms of exploitation." As one example of how conservation can be effective, he noted that in areas where scientific researchers work, animals stand a much better chance of surviving. "Where you have a research presence, it's as good or better than a guard force," he said.

Schipper offered the model of the U.S. effort to bring back the black-footed ferret, which was essentially extinct on the North American prairie as of 1996. "Now it's endangered, which, in this case, is a huge improvement," he said. "When governments and scientists commit resources to a project, many species can be recovered."

Monday's reports come as researchers have been documenting effects of human-generated greenhouse gases. In a paper published Thursday in the journal Geophysical Research Letters, a team at the Monterey Bay Aquarium Research Institute found that ocean acidification spurred by carbon emissions will cause sound to travel farther underwater, because increasingly acidic seawater absorbs less low- and mid-frequency sound.

By 2050, the researchers predicted, sounds could travel as much as 70 percent farther in parts of the Atlantic Ocean and other areas, which may improve marine mammals' ability to communicate but also increase background noise, which could prove disorienting.

"We understand the chemistry of the ocean is changing. The biological implications of that we really don't know," said ocean chemist Keith Hester, the lead writer. "The magnitude to which sound absorption will change, based mainly on human contribution, is really astounding."