Oak savanna restoration for the Karner blue butterfly
The Karner blue butterfly (Lycaeides melissa samuelis) is a federally endangered species and is only found in one location in Minnesota. This small, beautiful butterfly inhabits oak savanna and requires lupine plants on which to lay its eggs. Oak savannas are one of the rarest native plant communities in Minnesota. Once covering more than five million acres in Minnesota, less than 4500 acres of savanna remain today. Many of these acres are becoming overgrown or are being invaded by invasive species such as honeysuckle, buckthorn and Japanese barberry. The Nongame Wildlife Program is working in partnership with the Division of Fish and Wildlife to restore oak savannas, particularly in areas where the Karner blue butterfly are known to occur. This work is challenging because oak savannas and lupine need some disturbance such as fire to maintain them. The butterflies are not known to be able to survive fire.
The Nongame Wildlife Program conducts annual monitoring transects to get a population index for Karner blues. While our populations are very low, we are managing to keep hanging on. Current restoration efforts involve removing invasive species and reintroducing fire in three valleys in southeastern Minnesota. There are twelve oak savanna valleys identified for recovery, but currently the work is being done to the three highest priority sites. More than 40 acres of oak savanna is well on its way toward restoration. Hopefully, the Karner blues will follow suit.