Wisconsin Butterfly Conservation Program Could Be a Model for Future Efforts
By Ed Ricciuti
An endangered butterfly with a one-inch wingspan is the focus of a cutting-edge recovery program in Wisconsin that has become a model for other recovery plans for imperiled species. A history of the program, described in an article published in American Entomologist, could be a blueprint for similar efforts to save habitats and the species dependent on them, according to Gene Kritsky, editor-in-chief of the journal and Chair of Biology at Mount St. Joseph University in Cincinnati, OH.
The paper is “Conserving Karner Blue Butterflies in Wisconsin: A Development of Management Techniques.” Its authors are a father-daughter team, Robert J. Hess, retired from the Wisconsin Department of Natural Resources, and Dr. Anna N. Hess, formerly of the Wisconsin DNR and now with its counterpart in Minnesota.
An extremely specific diet and highly specialized habitat requirements make the Karner blue (Lycaeides melissa samuelis) more vulnerable to threats than species that are generalists. Its caterpillar feeds only on the leaves of wild lupine plants, which grow on dry, sandy patches in what are called “barrens,” a savanna-like landscape dotted with scrub oak and stands of jack pine. Of the original 32 million acres of barrens in the Upper Midwest, less than eight million remain — the biggest chunk in Wisconsin, with other areas in Ohio, Minnesota, Michigan, and Indiana. Scraps of similar habitat with Karner blues survive in New York and New Hampshire. In Wisconsin, the barrens are an ecotone, called the “tension zone,” where a mixed coniferous forest meets a hardwood forest to the south.
The Karner blue was identified only in 1944 in Karner, NY, by Lolita author Vladimir Nabokov, an entomologist as well as a novelist. By 1992, as its habitat dwindled, only one percent of the population survived and the United States Fish and Wildlife Service (USFWS) listed it as a federally endangered species.
Once a species is federally listed, public- and private-sector activities that can significantly modify or degrade its habitat are limited. Use of land can be severely curtailed, with each activity requiring an “incidental take” permit from the USFWS, a lengthy and involved bureaucratic process. A Habitat Conservation Plan (HCP), identifying how the take will be reduced and mitigated during economic development, must be approved before issuance of a permit.
The listing had an immediate impact in Wisconsin.
“The threat of “take … nearly brought Wisconsin’s forest industry, one of the state’s primary economic sectors, to a halt in the tension zone,” said the authors of the paper. USFWS regulation of habitat use not only bridles business interests, but can stir passions over property rights and even opposition to perceived overreach by the federal government. The Karner blue listing impacted parties ranging from power companies and farmers to local highway departments and land developers. With remarkable foresight, the Wisconsin DNR quickly involved these parties in a process to streamline the permit process, which not only made it more palatable to them but also enlisted them as willing partners in Karner blue conservation.
Over six years, the DNR and its partners birthed an HCP for the Karner blue that was the first of its kind in the nation. Never before had a blanket take permit and accompanying HCP been approved to cover the activities of multiple companies, agencies, and individuals across an entire state, the authors wrote. The agreement permit allows the partners – today, more than 40 in all — to operate under an umbrella incidental-take permit instead of applying individually to the USFWS for each activity and reapplying when the permits expire.
Announcement of the Karner blue HCP approval was attended with considerable hoopla from the USFSW. Then-U.S. Secretary of the Interior Bruce Babbitt declared, “This is the first comprehensive statewide HCP and the most inclusive agreement of its kind in the country,” calling it a model for other states to consider.
The USFWS has praised the program, saying it “represents a tremendous effort by a diverse partnership and has the potential to ensure habitat for the Karner blue butterfly in suitable areas across the state.”
The federal agency added that “the general public’s attitude toward endangered-species management has become much more positive. Collaboration has built trust between governments and citizens, enabling meaningful and widespread protection for the Karner blue.”
Partners carry on normal activities, such as mowing, herbicide applications, and timbering under legally binding conservation agreements with the state. Alliant Energy, which serves approximately 1 million electricity customers and 420,000 natural-gas customers in the Upper Midwest, is one such partner. It continues operating in butterfly habitat while limiting field activities during the Kaner blue’s flight season, and it trains crews to minimize their impact on wild lupine plants. Employees conduct wild lupine and butterfly surveys each year, focusing on habitat where line clearance or construction projects are scheduled.
Much of the disruption that occurs on Karner blue habitat actually helps the long-term survival of the species, even if it kills individual butterflies and eggs. Under natural conditions, the barrens succeed to mature forest, which shades out wild lupine. Browsing and grazing by wildlife, storms, and fires can slow the transition. Once mature, the forest may eventually revert to barrens after trees die due to insects and disease. Harvesting timber, prescribed burns, and mowing can replace the natural forces that maintain barrens.
From a management standpoint, the Karner blue HCP departed from the norm because it approached conservation over the entire range of the species in the state rather than focusing on small, localized populations. That’s important because butterflies “don’t recognize property lines,” Kritsky said.
Most Karner blue populations are small and separated, but are actually linked by dispersal. Karner blues usually produce two generations annually. In April, the first-generation caterpillars hatch from eggs deposited late in the previous summer. By mid-May, the caterpillars pupate, emerging from their chrysalises by May’s end or the beginning of June. By the end of June, these adults have mated and the females have deposited eggs. It takes only a week for the eggs to hatch as the year’s second generation of caterpillars. These, in turn, are adults in July. The eggs that result from their mating hatch the following spring.
The HCP takes into account that butterflies from one patch of lupine may disperse to others, creating a metapopulation composed of many smaller units. A “metapopulation,” according to the HCP, must cover at least 25 acres and have three to five subpopulations. Management can be tailored to even larger population units — more than 640 acres — containing at least 6,000 Karners. With this broad-brush approach, management can focus on the broad dynamics of shifting Karner blue populations over the landscape, rather than on small numbers of individuals in patches than can be no more than a few acres.
Approaching Karner blue conservation across a wide landscape of barrens takes on added significance in the light of climate change. The tension zone has a high level of biodiversity because it is the southern limit for many northern species, and it’s the northern limit for many with a southern range. Southern oaks meet northern pines, and the southern Louisiana water thrush encounters the northern snowshoe hare.
“As our global climate continues to warm, appropriate temperature regimes for the Karner blue and other barrens species are likely to move northward,” the authors wrote. New insights into barrens management may enable conservationists to create habitats that are stepping stones for Karner blues and other barrens species as they and their climatic zone shift to higher latitudes.