Wildlife extinction rates 'seriously underestimated'

Guardian (UK): Endangered species may become extinct 100 times faster than previously thought, scientists warned today, in a bleak re-assessment of the threat to global biodiversity. Writing in the journal Nature, leading ecologists claim that methods used to predict when species will die out are seriously flawed, and dramatically underestimate the speed at which some plants and animals will be wiped out.

The findings suggest that animals such as the western gorilla, the Sumatran tiger and the Malayan sun bear, the smallest of the bear family, may become extinct much sooner than conservationists feared.

Ecologists Brett Melbourne at the University of Colorado at Boulder and Alan Hastings at the University of California, Davis, said conservation organisations should use updated extinction models to urgently re-evaluate the risks to wildlife. "Some species could have months instead of years left, while other species that haven't even been identified as under threat yet should be listed as endangered," said Melbourne.

…The researchers analysed mathematical models used to predict extinction risks and found that while they included some factors that are crucial to predicting a species' survival, they overlooked others. For example, models took into account that some animals might die from rare accidents, such as falling out of a tree. They also included chance environmental threats, such as sudden heatwaves or rain storms that could kill animals off.

But Melbourne and Hastings highlighted two other factors that extinction models fail to include, the first being the proportion of males to females in a population, the second the difference in reproductive success between individuals in the group. When they factored these into risk assessments for species, they found the danger of them becoming extinct rose substantially.

"The older models could be severely overestimating the time to extinction. Some species could go extinct 100 times sooner than we expect," Melbourne said….

In danger of extinction: the sun bear, this one in captivity at the Chicago Zoo. Photo by Grendelkhan, Wikimedia Commons, under the terms of the GNU Free Documentation license, Version 1.2