自然：灌木蒿海洋

　　One of the most overlooked ecosystems in the America West is a massive sea of sagebrush that stretches across 11 states. This spartan landscape supports more than 170 species of birds and mammals. Among those that have adapted to survive here are the Greater Sage-Grouse. Today, they must contend with wells and pipelines tapping the resources buried deep below. The sagebrush and the grouse carry on, but they're losing ground.