Earth’s family of more than 5 000 mammal species – all “cousins” to human beings – are now collectively facing a greater crisis than at any other time in their 225-million-year history.
According to a new assessment being released this week, an estimated one in four of the scientifically described 5 487 mammal species are being pushed to extinction, where they will join the 76 mammals known to have permanently disappeared since 1500.
Some 188 mammals are in the highest threat category of “critically endangered,” including the Iberian Lynx which has a maximum population of somewhere between just 84 to 143 adults and which is continuing to decline because of a shortage of its primary prey, the European Rabbit.
In South Africa, the Riverine Rabbit was believed to number only about 250 adults, although recent discoveries of some new populations of this species may have pushed that number up slightly.
The shocking numbers come from the Global Mammal Assessment, the most comprehensive assessment of the world’s mammals.
Details of the assessment are being released in tomorrow’s issue of Science, (“The Status of the World’s Land and Marine Mammals: Diversity, Threat, and Knowledge”).
A Red List of endangered mammal species is also being unveiled at the International Union for the Conservation of Nature’s congress in Barcelona, Spain.
According to researchers who worked on the exhaustive study, somewhere between 25 percent and 36 percent of all mammal species may be in danger of extinction.
“It’s 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 is one of 103 authors of the Science paper.
Smith played a key role in the assessment conducted by more than 1 800 scientists from more than 130 countries working under the auspices of the International Union for Conservation of Nature, in collaboration with top institutions and universities.
“Mammals are important because they play key roles in ecosystems and provide important benefits to humans.
“If you lose a mammal, you often are in danger of losing many other species,” Smith explained.
The assessment shows that at least 1 141 of the 5 487 mammals on Earth are known to be threatened with extinction, but the real situation could be much worse as 836 mammals are listed as “data deficient”, Smith said.
Major causes are habitat loss and over-exploitation for terrestrial (land) mammals, and pollution, global warming, and over-exploitation for marine mammals.
Announcing the Red List, IUCN director-general Julia Marton-Lefevre said hundreds of species could be lost within just decades as a result of human behaviour.
“We must now set clear targets for the future to reverse this trend to ensure that our enduring legacy is not to wipe out many of our closest relatives.”
In the Science article, which includes the contributions of more than 1 700 scientists, the researchers state that 188 mammals are in the highest threat category of “critically endangered”.
China’s Père David’s Deer is listed as “extinct in the wild”. However, the captive and semi-captive populations have increased in recent years and it is possible that truly wild populations could be re-established soon, the authors note.
It may be too late, however, to save the additional 29 species that have been flagged as “critically endangered, possibly extinct”, including Cuba’s Little Earth Hutia – a rodent species – which has not been seen in nearly 40 years.