Karner Blue Butterfly Conservation 

The Detroit Zoo is participating in a federal recovery plan for the endangered Karner blue butterfly. Once common from Minnesota to Maine, populations of this butterfly are suffering due to loss of habitat. In many cases, local populations have disappeared entirely. The Zoo is working with the Michigan Department of Natural Resources to restore the oak savanna habitat at the Petersburg State Game Area near Dundee, where the butterfly was last seen about 20 years ago, to the proper plant community to support Karner blue butterflies. Once the group determines that the habitat is suitable, the Zoo can begin to breed Karner blue butterflies from stock taken from viable populations in western Michigan and release them at the restored site. It will probably take about six or seven years to establish a viable population in southeast Michigan.

Detroit Zoo Butterfly Program Coordinator Laura Harris, who heads the project, says, "The main factor endangering the Karner blue butterfly is habitat loss. The oak savanna is a fire-dependent habitat. Over time people have suppressed fires. What happens next is called succession: without fire, larger shrubs and trees begin to grow in open areas. The prairie species cannot thrive under the canopy of the trees and shrubs and they die out. Much of the restoration work involves re-creating the clearings, whether through physical brush removal or through controlled burning."

"This summer we’ve made a lot of progress by conducting controlled burns in several areas," Harris adds. "It helped native plants thrive and pushed back some invasive species. We’ve also planted several species of wild flower plugs and lots of lupine, which is the Karner’s one and only host plant. Data collection will help determine if the nectar plant and lupine densities would be appropriate to support the butterfly. Trial breeding began at the Zoo in 2007 in order to establish our protocol for raising Karner butterflies in captivity. We are targeting the summer of 2008 for release of captive-reared Karner blue butterflies at the restored site."