Prairies in the Hills

Prairies in the Hills. Iowa's Loess Hills. When Lewis and Clark saw western Iowa in 1804, the land was almost completely covered with prairie grasses and wildflowers. Now, very little of this vegetation remains. The largest tracts of undisturbed prairie found in Iowa are here in the Loess Hills. These prairie plants have lived here for thousands of years. Over 300 species of plants have been identified by biologists, many native to Iowa only in the Loess Hills. These prairies are classified as "mixed grass" prairies. They contain the "tall grass" species like switchgrass, big bluestem and Indiangrass, the "mid-grasses" such as little bluestem and side oats grama, and the "short grass" plants like blue grama and buffalograss. Prairie wildflowers, called forbs, share this habitat with the grasses. Some of the forbs commonly seen include leadplant, compass plant, coneflower, asters, blue eyed grass and yucca., Threats To The Prairie , Timber is a natural enemy of the sun loving prairie. The invading woody plants move slowly up hillsides, increasing in growth until their shade eliminates the prairie vegetation. The first plants to begin the assault are coralberry, sumac and dogwood. These plants produce the shade and wind protection allowing trees such as red cedar, burr oak, and others to sprout. In Iowa, trees are not rare like the native prairie. The mixture of forbs and grasses found in the Loess Hills evolved naturally here for thousands of years. Wildfires and herds of buffalo helped control the spread of trees and shrubs in pre-settlement times. These natural forces are no longer present. The challenge now for saving the remaining prairie is to stop the woody invasion. The primary management tool currently used to achieve this, is periodic burning of the prairie.