McCormack Loess Mounds
Points of Interest:
- See plants of the Great Plains without leaving Missouri.
- Enjoy views of the wide Missouri floodplain from the hill prairie summits.
- See flocks of waterfowl descend on Squaw Creek National Wildlife Refuge located below these loess hills.
Natural Features Description:
These steep hills are formed of loess – highly angular silt particles – that was deposited over a period of 10,000 years. Loess soil can hold together at sharp angles and is very well-drained. This combination of steep slopes that face south and west along with rapid internal soil drainage gives rise to environmental conditions more similar to the mixed-grass prairies of the Great Plains. In addition this part of Missouri only gets 37 inches of rain adding to the dry conditions of the loess hill prairies.
These loess hill prairies are dominated by a mix of mid-grass species, little bluestem, sideoats grama, plains muhly, and hairy grama, along with the tallgrasses, big bluestem and Indian grass. Wildflowers more typical of the Great Plains include downy painted cup, nine-anther prairie clover, and skeleton plant. Not only are there plant species here disjunct from the center of their ranges in the Great Plains, there are also a katydid, the prairie meadow katydid, and a grasshopper with a funny name, the short-winged boopie, that are more typical of the Great Plains. Research indicates that loess hill prairies need periodic fires to thrive. Fire scars on ancient bur oaks at nearby sites indicate that before 1820 fires occurred every six years in these hills. Today, Conservation Department employees use thinning and controlled fires to keep woody plants from taking over.
This natural area is within Jamerson C. McCormack Conservation Area. From Interstate 29 take exit 79 and head west on Highway 159. In about 3 miles you will see a conservation area parking lot on your left (east). Park here. A field access road serves as a hiking trail to provide access to the natural area. Hunting is permitted.