Species extinction threats underestimated

BOULDER, Colo., July 8 (UPI) -- A U.S. study finds species extinction threats are underestimated due to a math problem, with extinction risks underrated by possibly as much as 100-fold.

University of Colorado-Boulder Assistant Professor Brett Melbourne said current mathematical models used to determine extinction threat, or the "red-listed" status, of species overlook random differences between individuals in a given population.

He said such differences-- including variations in male-to-female sex ratios and size or behavioral variations among individuals -- can influence their survival rates and reproductive success, thereby exerting an unexpectedly large effect on extinction risk calculations.

"When we apply our new mathematical model to species extinction rates, it shows that things are worse than we thought," said Melbourne. "By accounting for random differences between individuals, extinction rates for endangered species can be orders of magnitude higher than conservation biologists have believed."

The research, funded by the National Science Foundation, is reported in the journal Nature.