/ 14 October 2008

On the brink

The scimitar-horned oryx
The scimitar-horned oryx

Nearly a quarter of the world’s land mammal species are at risk of extinction and many others may vanish before they are even known to science, according to an extensive survey of global wildlife.

At least 1 141 of the 5 487 known species of mammals are threatened, with 188 listed in the ”critically endangered” category. One in three marine mammals are also threatened, according to the five-year review.

The assessment, conducted by the International Union for the Conservation of Nature (IUCN) Red list, involved more than 1 700 experts in 130 countries and confirms the devastating impact of forest clearing, hunting, fisheries, pollution and climate change on the populations and ranges of the world’s most studied class of animals.

Jan Schipper, director of the global mammals assessment, a partnership between Conservation International and the IUCN, called for countries to be held responsible for the fate of fauna within their borders and an international coalition to save species that cross national boundaries.

”We’re looking at a 25% decline over the long term, yet for mammals there is no bail-out plan. There is no long-term conservation strategy that is going to prevent species extinction in the future,” he said. ”As human beings, we should be ensuring that we don’t cause other species to go extinct.” Disturbingly, the figures are likely to be a conservative estimate, because scientists have insufficient data on 836 species to even classify how threatened they are. If these are all at risk, it would mean 36% of the world’s mammal species are in danger of becoming extinct.

Among the critically endangered species is the Iberian lynx (Lynx pardinus), with only 84 to 143 adults remaining.

Experts believe 29 others may already have become extinct, including the Yangtze river dolphin and the little earth hutia, a small rodent endemic to islands off Cuba, which has not been seen in nearly 40 years. Two species, the scimitar-horned oryx and Pere David’s deer, are extinct in the wild and live on only in captivity. Many species, such as the grey wolf and brown bear, have experienced substantial population declines and seen their ranges contract as their habitats have been destroyed.

More than half of the world’s mammal species for which trends are known are in decline, the report found.

”We are getting far too used to seeing these reports bemoaning the fate of the planet or the decline of animals. I am really concerned that we have become deadened to this sort of depressing information and now simply ignore it without stopping to think about the implications,” said Mark Wright, chief scientist at World Wildlife Fund (WWF). ”The IUCN report shows that, with our ill-considered management of the earth and its resources, we are threatening the future of wildlife and nature and denying our children the chance to experience what we have experienced.”

The survey, which is published by the journal Science Today, identifies extinction hot spots where vast numbers of species are under threat.

Typically, these are regions with a rich diversity of species that all face a similar threat to their environment. Threatened land mammals are concentrated in south and south-east Asia. There, a staggering 79% of monkeys and apes face extinction. Other hot spots include the tropical Andes, the Cameroonian Highlands, the Albertine rift in central Africa and the Western Ghats in India.

”Often there is habitat loss from deforestation, either for farming or timber, and that leaves the animals living on small patches of land. Then, on top of that, you have hunting, with an enormous number of people who are entirely reliant on natural resources to feed themselves. That has really set up a perfect storm over south-east Asia,” said Schipper.

The greatest threats to marine mammals are being caught in fishing nets or being struck by shipping vessels, although for the Yangtze river dolphin pollution is a major contributor.

Climate change is already having an impact on amphibians and plant life, but it is expected to put increasing pressure on mammals too, either by destroying their environment, such as the Arctic ice sheets that are home to polar bears, or by forcing their prey elsewhere.

Among the most threatened mammals are those only recently discovered. Since 1992 349 new mammal species have been identified, but 51% of these face extinction, compared with 23% of species known before 1992. ”Species may be vanishing even before they are known to science,” the scientists write in the journal.

There is a glimmer of hope among the bleak assessments. At least 5% of the threatened species now have stable or rising populations, many of which are the focus of huge conservation efforts.

”The problem we face is that without the political and public will to spend money on species conservation, we are pressed up against the wall,” said Schipper. ”By making this data public, we’re hoping it’ll reach the people who make decisions about where money is spent.” —