The Central Plains Experimental Range is on the west side of the Grassland. Animals and plants evolve together, adapting to environmental conditions. The whole complex of interactions between species and their environment makes up the ecosystem. The shortgrass prairie ecosystem evolved from a climate where annual precipitation is low, between 12 and 15 inches, most of it coming as rain from April through June. This semiarid climate has low humidity, high winds, high rates of evaporation, and periodic severe drought.
Blue grama is the Colorado state grass.
Western wheatgrass, sideoats grama, sand dropseed, three-awn, and other grasses are also present. Another native, the prickly pear cactus, carpets the prairie with gorgeous pink and yellow flowers in late spring. Shrubs such as fourwing saltbush, chokecherry, and winterfat are common where soils are favorable. Animals of the prairie have adapted to the climate and vegetation. Mammals that are successful in living here are mainly grazers, who eat grasses and forbs, and burrowers, which live underground for protection from predators and extreme weather.