Prairies once covered much of North America from the Rocky Mountains to Indiana, with scattered prairies extending to the eastern seaboard, and tallgrass prairies once dominated much of Missouri. These ecosystems are home to more than 300 kinds of grasses and flowering plants along with abundant birds, insects, and other wildlife. Some prairie plants have root systems reaching as deep as 15 feet, allowing them to absorb and retain water and nutrients better than cool season grasses and making them better adapted to survive droughts and fire. Many prairie plants need fire to reproduce and stay healthy, and Native Americans, early settlers, and current conservation managers have used fire to manage prairies. More than 99 percent of Missouri's original prairies have been destroyed through conversion to agriculture, forest growth caused by the lack of fire, or human development, making protection of the remaining prairies especially important. The August A. Busch Memorial Conservation Area and the Weldon Spring Conservation Area contain 30 man-made fishing lakes built between the early 1950s and the early 2000s by damming small creeks and ravines, including Prairie Lake and nearby Fire Lake along Howell Trail. The Missouri Department of Conservation created and manages these lakes for year-round recreation and fishing, stocking them with Largemouth Bass, Crappie, Bluegill, Redear Sunfish, Channel Catfish, Flathead Catfish, Rainbow Trout, and Muskelluge. The department also manages the August A. Busch Memorial and Weldon Spring conservation areas to provide habitat for Missouri plant, fish, and wildlife species, while allowing licensed and permitted hunting for deer, turkey, rabbit, squirrel, dove, waterfowl, and other small game outside the trail.