Bad Math = More Extinctions

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


gone_rhino_300x398.jpg We may be underestimating extinction risks by as much as 100-fold. The problem is that current extinction models treat all individual members as the same. You know, one polar bear is more or less a behavioral, programmed clone of the next polar bear.

Ooops. Not so. A new model finds that random differences—male-to-female sex ratios, size differences, behavioral variations—affect individuals’ survival rates and reproductive success. These differences don’t just ripple outward. They tsunami outward into the overall population. Consequently, extinction rates for endangered species can be orders of magnitude higher than conservation biologists previously believed.

The model developed by Brett Melbourne of Colorado University Boulder and Alan Hastings of the University of California Davis monitored populations of beetles in lab cages. “The results showed the old models misdiagnosed the importance of different types of randomness, much like miscalculating the odds in an unfamiliar game of cards because you didn’t know the rules,” says Melbourne.

Some high-profile endangered species like mountain gorillas are already tracked individually. But for many others, like stocks of fish, biologists only measure abundance and population fluctuations. “It’s these species that are most likely to be misdiagnosed,” says Melbourne. “We suggest that extinction risk for many populations… need to be urgently re-evaluated with full consideration of all factors contributing to stochasticity, or randomness.”

The IUCN Red List tallies more than 16,000 species threatened with extinction worldwide. One in four mammal species, one in eight bird species and one in three amphibian species are teetering on the brink. The new study in Nature, “Extinction risk depends strongly on factors contributing to stochasticity,” makes those numbers look tame.

Julia Whitty is Mother Jones’ environmental correspondent, lecturer, and 2008 winner of the Kiriyama Prize and the John Burroughs Medal Award.

We've never been very good at being conservative.

And usually, that serves us well in doing the ambitious, hard-hitting journalism that you turn to Mother Jones for. But it also means we can't afford to come up short when it comes to scratching together the funds it takes to keep our team firing on all cylinders, and the truth is, we finished our budgeting cycle on June 30 about $100,000 short of our online goal.

This is no time to come up short. It's time to fight like hell, as our namesake would tell us to do, for a democracy where minority rule cannot impose an extreme agenda, where facts matter, and where accountability has a chance at the polls and in the press. If you value our reporting and you can right now, please help us dig out of the $100,000 hole we're starting our new budgeting cycle in with an always-needed and always-appreciated donation today.

payment methods

We've never been very good at being conservative.

And usually, that serves us well in doing the ambitious, hard-hitting journalism that you turn to Mother Jones for. But it also means we can't afford to come up short when it comes to scratching together the funds it takes to keep our team firing on all cylinders, and the truth is, we finished our budgeting cycle on June 30 about $100,000 short of our online goal.

This is no time to come up short. It's time to fight like hell, as our namesake would tell us to do, for a democracy where minority rule cannot impose an extreme agenda, where facts matter, and where accountability has a chance at the polls and in the press. If you value our reporting and you can right now, please help us dig out of the $100,000 hole we're starting our new budgeting cycle in with an always-needed and always-appreciated donation today.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate