Bison are a keystone species on the prairie. That means they have a large effect on the natural environment. Grazing is one example.
Grazing creates shorter grass heights, providing habitat for wildlife species that prefer sparse plants, like grasshopper sparrows. Bison mostly feed on grass, which opens space for more wildflowers to grow.
You may have noticed large bare areas throughout the bison enclosure. These are called wallows. Bison create these bare dirt depressions by rolling on the ground. They do this to get rid of biting insects, to shed hair, and to cool off when it is hot. Bulls also wallow to leave their scent and display their strength.
Wallows can actually be beneficial to prairie ecosystems. Large wallows collect water during rainfall, creating habitat for amphibians and aquatic insects. Some types of plants and invertebrates also benefit from the soil disturbance.
Another way bison shape the prairie is by moving seeds to different locations. As bison roam, they carry seeds in their stomachs and in their fur. This helps plants move throughout the prairie ecosystem. They also provide fertilizer that can help plants sprout. So even though our herd is relatively small, it has a large impact on the surrounding prairie.