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One-fourth of wild mammals face extinction

October 6, 2008 | 10:08 am

African_elephant

Barcelona, Spain -- At least one quarter of the world's mammals in the wild are threatened with extinction, according to an international survey released today that blames the loss of wildlife habitat as well as hunting and poaching for steep declines.

The survey, assembled over five years by 1,700 researchers in 130 countries, is the most comprehensive study ever done to assess the status and future of mammals on every continent and in every ocean.

The baiji, or Chinese River dolphin, is one of the latest mammals believed to have joined the growing list of species now extinct. Others are not far behind, such as the vaquita, a small porpoise that has been drowning in fishing nets in the northern part of the Gulf of California; the North Atlantic right whale; and various monkeys and other primates hunted by poachers in Africa.

In all, scientists have determined that about one quarter of the 5,487 mammals known on Earth are endangered or threatened with extinction. The proportion of marine mammals in trouble appears to be higher, with an estimated one-third facing a serious threat of being wiped out -- mostly through entanglement and drowning in fishing gear or being struck by ships.

About half of the world's remaining apes, monkeys and other primates face similar threats due to destruction of forests to make way for farming or to being hunted, said Russell A. Mittermeier, president of Conservation International.

"Chimp and gorilla meat fetches a higher price in many markets in Central African cities than beef or chicken because it's considered a luxury item," Mittermeier said. "We are losing many of these animals that otherwise could survive because they cling to relatively good habitat."

The bleak assessment was released today at the World Conservation Congress, a meeting of 8,000 scientists, conservationists, business leaders and representatives from governmental environmental ministries. It was part of a larger update to the Red List of all threatened species, maintained by the International Union for the Conservation of Nature (IUCN), which hosts this congress every four years.

Jonathan Baillie, director of conservation programs for the Zoological Society of London, said that a sampling shows that 24% of all vertebrates -- those animals with a backbone -- appear to face the same threat of extinction.

To track the health and abundance of all species is too massive a job, Baillie said, but he suggested that such sampling might be tantamount to creating a Dow Jones Industrial Average index for the planet's biodiveristy. In this case, though, he said, "There's no $700-billion dollar bailout on the horizon."

Holly Dublin, who leads the IUCN's species survival commission, said that more details of the Red List would be unveiled at various presentations and workshops this week in Barcelona as conservation biologists and international officials worked on plans to try to reverse the downward slide of so many species. For instance, she said, a clear picture of a species in trouble, along with information about its habitat, could discourage the World Bank from financing a development project that might imperil that species' existence.

Researchers have sought to make the IUCN's Red List the most trusted assessment of species vulnerability by accummulating the best scientific information without getting tied up in legal definitions or the politics of any particular nation.  The Red List used to be published as a book, but the list has grown so long -- now 44,838 species -- it has evolved into an online catalog at  IUCN.org.

The Red List has several categories, including extinct or extinct in the wild, critically endangered, endangered, and vulnerable to extinction.

Still, these assessments are far from an exact science. The La Palma giant lizard was thought to have become extinct in the last 500 years -- sometime after the Romans brought rats to the Canary Islands off the northwestern coast of Africa. But this lizard was rediscovered last year, clinging to steep cliff faces out of reach of rats. It's now listed as critically endangered.

So, the news isn't all bad. Some species have made a recovery in recent years. The black-footed ferret, for instance, is no longer extinct in the wild after the U.S. Fish and Wildlife Service mounted an extensive captive-breeding program and successfully reintroduced it into the wild in eight Western states. This ferret, which eats prairie dogs, now appears to have three small but self-sustaining populations in South Dakota and Wyoming.

The assessment of marine mammals, the first completed since 1996, did not fully factor in the effects of global warming, the principal scientists said. The results of this study will be published later this week in the journal Science.

Furthermore, the prospects for these animals, may be worse than even the global numbers suggest, said Jan Schipper of Conservation International, who was the lead author of the Science paper. The problem is what he called a surprising lack of information about 836 mammals.

"If you don't know where they are or how many there are, then it's hard to determine if they have viable populations or [are] threatened with extinction," Schipper said.  Given this uncertainty, as many as 36% of land mammals and 61% of whales, seals and other marine mammals could be threatened with extinction.

-- Kenneth R. Weiss

Photo: African elephant. Poached for ivory and meat, this species has declined by 25% since 1979, a drop that falls short of the 30% decline needed to qualify for the Red List category of "threatened with extinction." Credit: Alicia Wirtz

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