The one true historic prairie is the 12-acre Bear Lake Prairie, a marl beach/wet prairie located along the south shore of Bear Lake. This area was historically grazed until the 1970’s. In the 1980’s sporadic controlled fire was introduced, but it did not eliminate the larger browse-resistant hawthorn trees and other larger scattered woody vegetation. In the early 1990’s a concerted effort was undertaken to eliminate woody tree species by cutting and treating their stumps with herbicide. Isolated patches of grey dogwood shrubs were left for nesting habitat, along with scattered red-osier dogwood shrubs. Prescribed fire was introduced on a more regular basis in the mid-1990’s, and continues to be done on a 3-5 year interval. Periodic work continues to remove the woody growth encroaching on the prairie perimeter, and to gradually extend the area exposed to sunlight. The prairie’s adjacency to the Onion Bottoms wetland results in a significantly diverse ecotone that has increased in plant diversity over the years as periodic fire has been introduced.