North Dakota has enjoyed a booming economy in the past decade, but it has paid for that growth with vast stretches of ecologically rich grasslands, The Washington Post reports. The state is part of the “Prairie Pothole Region,” a grassy swathe pitted with shallow wetlands that stretches from Alberta to Iowa. The habitat is home to diverse plants and animals, including more than half of the United States’ migratory ducks. Thousands of acres of mixed grass prairie have been converted to single-crop farmland, and oil rigs have popped up on ecologically sensitive wetlands. More than 90 percent of prairie pothole grassland in the eastern Dakotas is privately owned, and federal incentive programs such as the Conservation Reserve Program haven’t been enough to persuade landowners to preserve the ecosystem.