Application of the fire-grazing interaction model for conservation in the tallgrass prairie of Oklahoma

Background/Question/Methods

The 1.5M ha Flint Hills of Kansas and Oklahoma comprise the largest tallgrass prairie landscape in North America.  Fire is regularly applied by ranch managers across a sizable portion of this privately-owned landscape. Grazing regimens typically stress uniformity which combined with high fire frequency result in a largely homogeneous landscape with lowered biodiversity potential.  Increasing landscape heterogeneity is a goal of The Nature Conservancy (TNC) in the Flint Hills.The first step in addressing the landscape homogeneity concern has been development and demonstration of biodiversity-focused range management tools.  At TNC’s 16,100 ha Tallgrass Prairie Preserve in northeastern Oklahoma, a free-ranging bison herd has for the past 18 years interacted with randomly selected burn patches that approximate historic seasonality and frequency of fire.  Currently, 2,700 bison graze on 9,600 ha of tallgrass prairie and crosstimbers woodlands.  The fire-bison interaction produces a vegetative structural and compositional heterogeneity in an ever-shifting landscape patch mosaic.

Results/Conclusions

Realizing that a fire-bison regime is not likely to be highly exportable to the private ranching sector, TNC has been working with university research partners to develop cattle management regimes that incorporate some of the same “biodiversity friendly” elements as fire-bison.  Oklahoma State University has been the leader in the development of “patch-burn grazing” regimes that promote heterogeneity using cattle, and directly challenge the long-held “evenness of use” paradigm of range management.  Over 4,600 ha at the Tallgrass Prairie Preserve is dedicated to cattle patch-burn grazing research and demonstration.  Research results have been encouraging:  heterogeneity and biodiversity can be enhanced with little or no decrease in livestock production.  The next step is implementation at the landscape scale, and a host of tools and strategies are being developed to promote heterogeneity-focused range management practices in the Flint Hills.