Researchers document world's mammals in crisis

From the report: From majestic African elephants to tiny and often unappreciated rodents, mammals on Earth are in a state of crisis. One in four mammal species on Earth is being pushed to extinction, according to the Global Mammal Assessment, the most comprehensive assessment of the world's mammals.

Writing in the October 10 issue of Science, ("The Status of the World's Land and Marine Mammals: Diversity, Threat, and Knowledge") and unveiling a "Red List" of endangered mammal species (at the International Union for Conservation of Nature World Conservation Congress in Barcelona, Spain), the researchers who worked on the exhaustive study say that from 25 percent to 36 percent of species may be in danger of extinction.

"It is frightening that after millions and millions of years of evolution that have given rise to the biodiversity of mammals we are perched on a crisis where 25 percent of species are threatened with being lost forever," said Andrew Smith, an Arizona State University professor who played a key role in the mammalian assessment. Smith and his research assistant, Charlotte Johnson, are two of the 103 authors of the Science paper.

The Global Mammal Assessment was conducted by more than 1,800 scientists from more than 130 countries working under the auspices of the International Union for Conservation of Nature. It was made possible by the volunteer help of IUCN Species Survival Commission's specialist groups and collaborations between top institutions and universities, including Arizona State University, Texas A&M University, University of Virginia, Conservation International, Sapienza Università di Roma and the Zoological Society of London.

The mammal assessment is the first comprehensive look at the health of terrestrial and marine mammals across the globe. It is a companion assessment to similar documentation of the world's amphibians, released four years ago by IUCN.

"Mammals are important because they play key roles in ecosystems and provide important benefits to humans," Smith explained. "If you lose a mammal, you often are in danger of losing many other species."

The assessment shows that at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction. At least 76 mammals have become extinct since 1500. The real situation could be much worse as 836 mammals are listed as "data deficient."

The culprits driving this precarious position include habitat loss and over exploitation for terrestrial mammals, and pollution, global warming and over exploitation for marine mammals, Smith said.

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