Fire was an important component in keeping the brush from overpopulating rangelands and keeping the grasses in a healthy state. Plants are influenced by soil types which compose ecological sites. Locate an area where this is evident. For instance, post oak grows on shallow soils, grasses grow on prairie soils. These are different soils and ecological sites.
Animals convert sunlight that is stored in the forage plants they eat.
This would include both livestock and wildlife. Since humans cannot live by eating the grass or shrubs, they must rely on the animals to convert this forage into something usable. The rangeland is a complex system. The quality of water and the production of food and fiber for now and for future generations is dependent upon how well the range and grasslands are managed. Depending upon your location, most of the land was open prairies with scattered timber except for the forested areas.