Before 19th century cultivation, most of the agricultural Midwest, including western and northern Missouri, was covered by tallgrass prairie (fig. 1). About 95 percent of the original tallgrass prairie in the United States has been converted to other land covers (Samson and Knopf, 1994), and less than one percent of the original tallgrass prairie in Missouri remains (Schroeder, 1982; Samson and Knopf, 1994).