Fire, whether human-caused or started by lightning, has been a part of the prairie ecosystem for thousands of years. Grassland species of the northern great plains evolved under periodic disturbance and defoliation from bison and fire. This periodic disturbance kept the grasslands healthy for thousands of years and is needed to keep them healthy today. It has been one way that the prairie ecosystem has been continually maintained and restored. The Refuge is located in the mixed-grass ecosystem, a geographical area which has been subjected to the effects of fire for centuries. The historical fire frequency on the mixed grass prairie is believed to be once in every 5 to 7 years.
Historic records describe huge prairie fires started by lightning or humans. Reports of early accounts by explorers viewed prairie wildfires as a feeling of danger, a risk, and a spectacle. Lightning-set fires were common in the United States and Canada, however, fires set by native peoples were the type mentioned most often in historical journals, diaries and various other accounts. Throughout the area, the Lakota Sioux set fire to the prairie to provide lush new growth to attract bison.
Fire constitutes one of the most important ecological processes of the prairie ecosystem. Fire may have a severe short term effect while it yields long term positive effects. Fire may expose the soil, increasing soil temperatures and lengthening the growing season. It kills or reduces vigor in some plants and stimulates and invigorates others. Fire quickly cycles nutrients in a prairie by converting plant litter and standing growth to ash, which is absorbed into the soil and made available for plant uptake.
The Refuge has used prescribed fire periodically to manage resources and reduce fuel loadings. From 1969 to 1997, the Refuge conducted 26 burns for a total of 3,453 acres. This is an average of less than one burn per year. In 1997, the Refuge initiated an aggressive prescribed fire program and increased the use of prescribed fire to manage refuge habitat resources. The refuge has prescribed burned over 8,000 acres since 1997, and has plans to continue to treat approximately 2,000 acres annually.