One-fourth of wild mammal species may face extinction, shows survey

The baiji, or Chinese river dolphin, is teetering on the edge of extinction and may have already joined the list of species that have vanished from Earth. Others are not far behind.

Scientists have determined that about 25% of the world’s 5,487 species of mammals face extinction. The proportion of marine mammals in trouble appears to be higher, with an estimated one-third under serious threat of being wiped out. Many are killed when they are struck by ships or become entangled in fishing gear.

About half the world’s remaining species of apes, monkeys and other primates face threats from hunting or deforestation to make way for farming, 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.”

Scientists find these extinctions particularly worrisome because a diversity of species helps stabilise the planet. Each extinction can disrupt this balance and ripple through the food chain, making it more difficult for other species, including humans, to survive.

The bleak assessment was released in Barcelona 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.

The Red List has several categories, including extinct; extinct in the wild; and those threatened with extinction, including the critically endangered, endangered and vulnerable.

Jonathan Baillie, director of conservation programs for the Zoological Society of London, said that a sampling shows that 24% of all species of vertebrates appear to face the threat of extinction.

Holly Dublin, who leads the IUCN’s species survival commission, said more details of the Red List would be unveiled in Barcelona this week.

Researchers have sought to make the IUCN’s Red List the most trusted assessment of species vulnerability by accumulating 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 it has grown so long — now 44,838 species — that it has evolved into an online catalog at iucn.org/redlist.

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 this week in the journal Science.