| Scope and method of study. Grazing distribution patterns and behavioral observations were used to assess the range ecology and physical effects of bison reintroduced to a tallgrass prairie site in Oklahoma. Patterns of grazing distribution were analyzed in relation to a prescribed Seasonal burning program initiated on the site in 1993. Microhistological fecal analysis was used to investigate seasonal botanical composition of bison diets. The effects of bison horning and wallowing behavior on the physical structure and diversity of the site was assessed by comparing landscape structure before and after bison reintroduction. Social and seasonal patterns in these two behaviors were assessed from behavioral observations.;Findings and conclusions. All types of seasonal burns were preferentially grazed by bison; unburned areas generally were avoided except by bull groups. Regression analysis revealed that the age and size of prescribed burn patches accounted for a significant amount of variation in bison grazing patterns. The most prominent vegetation group on the site, tallgrasses, was predictably the largest dietary component across all seasons. Sedges also were prominent in the diet, despite being relatively uncommon in the study area compared to grasses. Forbs were strongly and consistently avoided as a food item by bison. Diets varied also by season, with sedges being more prominent in winter and spring, and decreasing in summer and fall. Bison homing behavior significantly affected small trees and other small woody vegetation in the study area. About 4% of the small woody vegetation present on the landscape at the time of bison reintroduction was severely damaged or destroyed by bison rubbing and horning in a 2-year period. Willows were especially affected by bison, which was likely due to their widespread occurrence in the study area. Bison wallowed throughout the year. Numerous new wallows were formed by bison at higher elevations on sandy soils. Wallow distribution was associated closely with the prescribed burn pattern on the landscape. |
