Hit the snooze on that ecological doomsday clock for a minute: The world's species may not be going extinct quite as fast as we thought they were. Scientists may be overestimating the crisis by as much as 160%, according to a recent study.

The research was published online Wednesday in the journal Nature.

While stressing that the global extinction crisis is still indeed a crisis, the study's two authors called for a better mathematical model to predict how fast the world's diversity is disappearing.

The massive loss of species occurring today may constitute the sixth mass extinction of life on Earth. It is caused in large part by habitat destruction, which can be blamed on human encroachment. The rate of biodiversity loss, however, is difficult to estimate, said study coauthor Stephen Hubbell, an ecologist at UCLA.

One of the models that scientists use reverses what's called the species-area relationship: This starts with the number of species in a certain area and then measures how many new species pop up as the surveyed area increases.

Extinction rates, at first glance, should be the opposite of that relationship — losing species as land is lost. So researchers run the equation backward to calculate how fast species are disappearing.

But that's not an entirely accurate way to measure extinction, Hubbell said. The species-area relationship counts the first member of each species to appear — so running it backward would count the first member of each species to disappear. But just because one individual dies doesn't mean all of them have, he said.

To read the full article by Amina Khan click here.

Published: Monday, May 23, 2011

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