A comparison of adult butterfly communities on remnant and planted prairies in Northeast Iowa

Tallgrass prairie now covers less than 0.1% of its historic range in Iowa.  As the prairie declined, so did populations of native butterfly species like the Regal Fritillary (Speyeria idalia), Poweshiek Skipperling (Oarisma poweshiek), and Monarch Butterfly (Danaus plexippus). Prairie plantings have been used to reconstruct tallgrass prairie habitat. The goal of this project was to compare adult butterfly abundance and diversity between remnant prairies and prairie plantings. If prairie plantings are successful in restoring prairie function and structure, we expected that there would be no difference in abundance or diversity between planted and remnant prairies. Surveys were conducted in 4 planted and 4 remnant prairies during the summer of 2015 in Northeast Iowa. A modified “Pollard Walk” technique was used following a meandering transect in each prairie at approximately 3 week intervals. Butterfly sightings were recorded using the Unified Butterfly Recorder (UBR) app which records geographic position of each sighting. Identifications were done “on the wing” and butterflies collected only when necessary for identification. If a butterfly was observed nectaring on a flower, the species of flower was also recorded. Overall, 2863 butterflies representing 42 species were observed.  Surprisingly, monarchs (n=544) were the most common butterfly observed in 2015, but no regal fritillaries or Poweshiek skipperlings were observed at several sites that previously hosted them.  Overall, almost twice as many butterflies were observed on remnant prairies (n=1870) compared to planted prairies (n=993), although species richness was slightly higher on planted prairies (36 species) than remnant prairies (34 species).