A Changing Landscape
Wind, rain and the Little Missouri River carved the distinctive “badlands” from the plains and its underlying sedimentary rock. These geologic forces expose and constantly alter bands of sandstone, bentonite clay, and lignite coal. Although yearly rainfall totals less than 15 inches, it often arrives during heavy downpours that cause erosion. Lightning strikes and prairie fires can ignite the lignite coal. Sometimes burning for years, the coal veins bake nearby sediments into a brick-like rock known locally as scoria that is harder and more resistant to erosion than surrounding material. Erosion’s differential effect on this juxtaposition of hard and soft materials has produced the buttes, knobs and ridges common in the western landscape.
Animals have also altered the landscape. Grazing animals like pronghorn, mule deer, elk, bison and prairie dogs have influenced Plains plant ecology. Beavers altered the direction and flow of streams and rivers, cutting into and eroding new areas of the soft rock.
Humans, in particular European settlers, have had a dramatic impact on the landscape. Railroads and roads disrupted normal animal migration patterns. Ranching altered the number and distribution of herbivores, seen as competitors for grazing. Once enormous populations of bison faced near extinction after settlers spread across the plains. Large predators were exterminated because they posed a risk to livestock. Farming has replaced native plant ecosystems with uniform swaths of crops, significantly reducing plant and animal diversity. Use of herbicides and pesticides further reduced remaining natural plant and insect communities.
The pace and scale of human impact on the landscape has increased dramatically with industrialization and the emergence of the fossil-fuel based economy. Mining, oil and gas development bring disturbance, traffic and pollution to local areas. These practices and the economy that drives them also have wide-spread, long-term impacts on the landscape as burning of fossil fuels contributes to climate change.