Effect of management on butterfly and ground beetle diversity in simple and diverse prairie plantings in a reconstructed prairie

Anderson Prairie is a reconstructed tallgrass prairie in Decorah, Iowa, that was planted by Luther College in two stages.  The older planting (1988) was a simple mix of 18 native species, and the newer planting (1998) was a diverse mix containing 76 native species.  To maintain tallgrass prairies, natural periodic disturbances such as fire and grazing are essential.  Anderson Prairie is managed with prescribed fire and mowing (to mimic grazing).  The goal of this study was to compare the effects of burning and mowing treatments of simple and diverse prairie plantings on butterfly (herbivore) and ground beetle (predator) communities, both significant components of the overall biodiversity of tallgrass prairies.  Sampling for plants, butterflies, and ground beetles occurred from June through September 2011 with three replicates in each of the four treatment combinations (simple burned, simple mowed, diverse burned, and diverse mowed).  Species richness, overall abundance, and Shannon diversity indices of the plant, butterfly, and ground beetle communities, as well as overall plant productivity were determined.  As expected, plant species richness was greatest in the diverse plantings, with the fewest species found in the simple mowed treatment.  There was a higher abundance and diversity of butterflies and ground beetles in the diverse mowed treatments, indicating that fire may have a detrimental impact on insect biodiversity.