Science and experience show that the resources national parks are set aside to preserve are affected by conditions beyond their boundaries. Yellowstone National Park, for example, encompasses 2 million acres, but less than 10 percent of the greater ecosystem required to support viable populations of its wildlife. From this, the oldest national park, to the newest conservation initiative—Colorado Plateau Dark Skies Cooperative formed to protect natural darkness and starry skies—the National Park Service is scaling up conservation across large landscapes.