Waubay National Wildlife Refuge lies in the Prairie Pothole Region of the northern Great Plains, where shallow wetlands scattered across the prairie were formed about 10,000 years ago when glaciers scoured the landscape, gouged out millions of basins, and left them to fill with water as the ice melted. Today this region provides important habitat for more than 50 percent of the continent's waterfowl. Prairie potholes are natural, shallow wetlands, many of them seasonal and dry during warmer months, and they provide water and food resources for hundreds of species while also replenishing groundwater, filtering nutrients and chemicals, and sustaining critical wildlife habitat. Ducks need grass for nesting, and grassland species such as sharp-tailed grouse also benefit from conservation of grasslands and prairie potholes. Fire towers remain as relics of the past, while fire is now used as a tool to manage grassland habitat through prescribed burns that help control invasive species and rejuvenate native prairie plants. Prairie plants are adapted to survive and even thrive after fire, including wildfires, and Maximillian sunflower is one of hundreds of flower and grass species that make up tallgrass prairie.