by Rachael Moeller Gorman



Graphic by Matt Zang

Despite all the ways humans reshape the land, roughly half our planet remains wild. Using on-the-ground measurements and satellite imagery, researchers sponsored by Conservation International—a nonprofit environmental organization in Washington, D.C.—identified 37 wilderness regions that cover 54 percent of Earth's land. These regions are defined as patches larger than 6,200 square miles that retain at least 70 percent of their original vegetation and that harbor fewer than 15 people per square mile. Better still, 17 percent of the world's plant species are concentrated in five high-biodiversity wilderness areas that cover just 6 percent of Earth's surface. These sparsely populated areas are obvious targets for conservation efforts, yet the vast majority of their area is not protected. Gustavo Fonseca, executive director of the Center for Applied Biodiversity Science at Conservation International, worries about threats from mining, grazing, deforestation, and other human activities. "It's now a question of whether we can get ahead of development trends and establish protected areas and more benign land uses," he says.