Species already listed as endangered may be racing toward extinction 100 times faster than originally thought, according to a new study led by the University of Colorado at Boulder.
Author Brett Melbourne says today’s extinction-risk models have drastically underestimated the speed at which endangered species will perish.
“It’s a mathematical misdiagnosis,” said Melbourne, an assistant professor in the ecology and evolutionary biology department at CU-Boulder.
According to the study, current extinction models factor in only random, unavoidable acts — for instance, an animal being run over by a car — and external, random events, such as climate change or weather impacts that can affect birth and death rates.
Melbourne says those calculations leave out important factors: the number of males versus females, and size and behavioral variations.
The study, published today in the journal Nature, immediately drew the interest of conservationists nationwide.
“I think what they have done is provide a technical, important fix to help us build a better mathematical model for small populations,” said Stuart Pimm, a conservation ecologist with Duke University. “It’s important that these mathematical models recognize these factors,” he added.
The revelation is apt to affect few of the 16,000 species worldwide currently listed by the International Union for Conservation of Nature, formerly the World Conservation Union, as threatened with extinction.
That’s because most of the plants and animals on that list already exist in such small numbers that mathematical models predicting their extinction were not necessary.
Pimm said at least 99 percent of the species on the 2007 Red List of Threatened Species, compiled by the IUCN, “are not based on mathematical models at all.”
But if Melbourne’s work gains traction in the conservation field, it could lead to a dramatic expansion of the number of species added to that “red list.”
“There could be thousands of species that aren’t on the list simply because their populations were large enough,” Melbourne said. “It is quite important to go back to these species.”
The study was co-authored by Alan Hastings of the University of California-Davis. “We hope that conservation biologists will think about our mathematical framework,” Melbourne said. “Our study is really a springboard for more detailed work.”
Steve Graff: 303-954-1661 or sgraff@denverpost.com
