Prior to Euro-American settlement, the Loess Hills were characterized by a diverse assemblage of prairie, bur oak savanna, and scattered pockets of bur oak woodlands. These biological communities are dependent upon frequent fire (average fire return interval is speculated to have been 3-7 years but evidence suggests it may have been annual) and periodic grazing. In the past, fires were ignited seasonally by lightning and by Native Americans for agricultural purposes, travel, and warfare, and grazing was primarily attributed to bison and elk herds.
During the late 1800s and early 1900s farmers burned the Loess Hills to stimulate forage production and remove invasive brush. Since then, throughout much of the Loess Hills the development of towns, roads, and farmlands, combined with rigorous fire suppression, have effectively eliminated the ecological force of fire. The native ungulates were extirpated from the region as well.
The removal of bison and elk and the elimination of fire has resulted in a continuing degradation of the biological communities in the Loess Hills. Restoring the fire and grazing regimes are necessary to renew the integrity of the entire system.