The Effects of Patch-Burn Grazing on Vegetation Structural Heterogeneity in the Northern Tallgrass Prairie of South Dakota

Abstract

Patch-burn grazing was developed as a grazing system to increase vegetation structural heterogeneity in managed grasslands of the central Great Plains. To evaluate this system in northern tallgrass prairie, we compared the structural response of vegetation following patch-burn grazing to that of continuous season-long grazing at two sites in eastern South Dakota. We established two pastures at each site and randomly assigned one pasture at each site to a patch-burn grazing treatment and the other to a continuous season-long grazing treatment. We allotted cow-calf pairs to each pasture during the summers of 2007 through 2009. We burned one patch of the patch-burn grazing pastures each spring for three years, leaving one patch not burned at the end of the study. We measured foliar cover of major plant functional groups, litter cover, and visual obstruction at the end of each grazing season and measured forage quality three times during the final summer. Ordination of principal component patch means showed greater vegetation structural heterogeneity for patch-burn grazing than season-long continuous grazing each year. Our results suggest that patch-burn grazing is a strategy that has potential to increase vegetation structural heterogeneity in northern tallgrass prairies and should be tested at other northern locations.