Extinction rates challenged by University of Alberta scientist

(Edmonton) A widely used scientific method of estimating extinction rates of various species on the planet is being challenged by a University of Alberta scientist, and the findings indicate that those losses may be vastly overestimated.

Using mathematical data, Fangliang He of the University of Alberta and his colleague, Stephen Hubbell of the University of California, have found that a formula used to predict species extinction due to habitat loss is flawed, and can therefore lead to inaccurate calculations.

Using large mapped forest plots and habitat ranges of birds in the United States, the researchers were able to show that over-estimation of impending extinction caused by habitat loss, can be more than 160 per cent.

“Mathematically, we have proven that this method for estimating extinction rates is flawed,” said He, a Canada Research Chair of biodiversity and landscape modelling, and professor of renewable resources in the Faculty of Agricultural, Life and Environmental Sciences at the U of A.

The research appears online in the latest issue of Nature.

Currently, the formula used by scientists to determine extinction rates is based on calculating species loss by reversing the curve describing how the number of species rises as more habitat area is examined. But the research of He and Hubbell contends that the habitat area required to remove the last plant or animal of its kind is almost always much larger than the sample area needed to encounter the first individual of a species.

That said, “habitat loss is real and is a growing threat to the survival of many species,” He noted. “These results don’t mean the world can be complacent about extinction.”

Improving geographical databases on the distribution of biodiversity around the globe for more accurate results “should be an international priority”, He said. “We currently only have knowledge about the threatened status for less than three per cent of a total of two million known species on Earth. A database on geographical distribution of species is essential to assessing endangered status for many more species.

“The good news about these findings is that it buys us, as scientists and conservationists, some time to conserve biodiversity,” he added.

Nature article: http://www.nature.com/nature/journal/v473/n7347/full/nature09985.html