Concurrent Effects of Fire Regime, Grazing and Bison Wallowing on Tallgrass Prairie Vegetation

We examined the effects of fire regime and bison activity on the plant communities of active bison wallows and the surrounding grazing lawns at Konza Prairie Biological Station in northeastern Kansas, USA. In both mid-June and late July the grazed sites had higher species richness and more vegetation cover than the wallow edges regardless of fire regime. The percent cover of most dominant perennial species was significantly higher on grazing lawns than in wallows. Annual species and exotic species had significantly higher cover in wallows than in grazing lawns and in annually burned sites compared to those burned at a 4-y interval. Overall, treatment effects on community structure and individual species abundance were stronger in the June. However, in July there was significantly more bare ground wallows around sites burned at a 4-y interval, suggesting increased wallowing activity at these sites. This finding suggests a strong effect of fire regime on seasonal bison activity, which further indicates the importance of multiple interacting disturbances for generating local- and landscape-level vegetation patterns in tall grass prairie.