Lost Biodiversity

A study published in Science by lead author Tim Newbold of the United Nations Environment Programme and University College London finds that 58 percent of the land area has undergone a loss of biodiversity beyond the "safe" boundary. Chris Mooney explains.

As a conservative or precautionary standard, the researchers therefore assumed that a decline of more than 10 percent of species abundance in a given area (compared with what that abundance was before human interference) represented crossing into a danger zone for biodiversity. But their study found that overall, across the globe, the average decline is already more like 15 percent. In other words, original species are only about 85 percent as abundant (84.6 percent to be precise) as they were before human land-use changes.