American Indians used fire in a variety of ways, but primarily as a hunting tool. A 1680 account by Father Louis Hennepin described how American Indians would set fire to the grass all around a herd of bison, allowing only one passage for escape. The hunters would station themselves along this passage, sometimes killing as many as 120 bison in one day. These autumnal fires promoted new growth in the spring, which attracted herds of bison. Today, park staff members replicate the impacts of American Indian and lightening-set fires through prescribed burns.
Grazing is equally important in maintaining a prairie ecosystem.
Missouri grasslands were once occupied by great herds of bison, elk and deer. The last elk herds were driven from the state in the early 1800s, and the great herds of bison were hunted nearly to extinction, by 1890. To help restore the effect of grazing, bison were reintroduced to Prairie State Park in 1987, and elk in 1993. The current size of the park bison herd is 45, with 19 calves expected to arrive soon. Grazing and fire play crucial roles in supporting prairie life.