Ecoregion 52b : Paleozoic Plateau (Driftless Area)

The bedrock-dominated terrain of the Paleozoic Plateau ecoregion is strikingly different from the rest of Iowa. Steep slopes and bluffs, higher relief, sedimentary rock outcrops, dense forests, and unique boreal microhabitats differentiate this ecoregion from the Western Cornbelt Plains to the west. The Silurian Escarpment, a prominent physiographic feature that helps define the southern and western boundary this ecoregion, separates the mostly cropland area of the west from the mixed land use of the Driftless Area. Dissolution of the limestone and dolomite rocks results in karst features such as sinkholes, caves, and springs, and makes groundwater vulnerable to contamination. The streams in the Iowa portion of this region occupy entrenched valleys, and have cool waters with high gradients flowing over rocky substrates. The fish communities found here reflect this preference for cool clear water with relative consistency of flow.