Karner blue butterfly program gets wings
"We don't know what the impacts of climate change will be. To be ready for it, we need to have the tools in place to respond to short or long term changes in the climate. Once the egg moving technique is proven, within a year or two, we'll be capable of moving butterflies to newly restored areas. If things get hotter and dryer, and as populations become stressed, we can move the butterflies north as needed."
That was U.S. Fish and Wildlife Service (USFWS) Biologist Chris Trosen, talking about the potential impact of an innovative new project designed to assist the migration of Karner blue butterflies.
Last December, the USFWS awarded a total of $803,000 to St. Croix Wetlands Management District (SCWMD) to distribute to public and private partners to identify and restore habitat to assist migration of the Karner blue butterfly. Large-scale habitat loss and degradation across the historic range of the butterfly led to its listing as a federally endangered species in 1992.
Cooperative agreements will provide $100,000 to the Wisconsin Department of Natural Resources (WDNR), $150,000 to the St. Croix River Association (SCRA) and $150,000 to the University of Minnesota (UMN). The balance of the funding will be used to purchase materials and hire staff and independent contractors.
At the heart of the grant is a concept that has been widely speculated about but never tested. If proven, it will dramatically impact both the technique and economics of propagating the Karner blue butterfly.
The grant, two years in the works, will help realize a concept championed by WDNR Area Supervisor Pete Engman.
"We were talking about the methods of moving butterflies from one place to another. We've done a lot of oak savanna restoration on Fish and Wildlife land in St. Croix County and southern Polk County and Karner blue butterflies really like oak savanna. Pete suggested, 'Why don't you just move the eggs.' Historically, folks have moved Karner blue butterflies by capturing adult females, bringing them into captivity to allow them to lay eggs, letting the eggs hatch and become adults, then releasing the adults back out in the field in areas where they don't have butterflies or they want to increase the existing population," explained Trosen.
The live capture method works but it's expensive, as much as several hundred dollars per butterfly.
Phase one of the project is the most important, testing whether Karner blue eggs can be harvested in the wild and propagated indoors.
For the last two years, volunteers from the Friends of the SCWMD along with students from New Richmond High School agriscience teacher Rachel Sauvola's classes have been planting native lupine on USFWS Waterfowl Production Areas preparing habitat for the re-introduction of Karner blue butterflies. This year, the students have also been growing lupine indoors in a greenhouse on campus awaiting the arrival of eggs to be harvested by University of Minnesota graduate students.
Native lupine provides the sole food source for Karner blue larvae; the same role milkweed plays for Monarch butterflies.
The grad students, under the supervision of the WDNR, will use endangered species permitting to collect Karner blue eggs from the population located in the Crex Meadows and Fish Lake Wildlife Areas in Wisconsin. They will transport the eggs to New Richmond High School and relocate the eggs next to the lupine in the greenhouse. The added protection and control provided by the greenhouse should maximize the survival of the first flight and second flights of the butterflies.
Karner blue eggs look like tiny white hats about the size of a plastic pinhead with an indentation in the middle. They can be found within 6 inches of the ground on or near lupine. After hatching, the larva will move up to 2 meters to find the stems of lupine. The students will need to relocate the eggs close enough to the stems of the Lupine for the larva to find them.
Karner blue butterflies propagate in two flights. The spring flight lays eggs within seven to 10 days of becoming adults. Those eggs then hatch the following spring. Karner blue butterflies only migrate up to two miles emphasizing how critical it is to link suitable regions of habitat together to create corridors to enable the butterflies to move should their habitat become too hot or dry.
Phase two of the plan is to move the project outdoors, releasing the adults into the restored habitat in the waterfowl production areas in Wisconsin and Minnesota and continuing to relocate eggs into the habitat as well. The habitat will be evaluated this year with the plan to begin organized releases in 2018.
Butterfly landing sites will be evaluated for percentage and mixture of canopy, a key characteristic in determining suitable habitat for Karner blues. The habitat must have enough lupine to support the larva and young adults and also enough early spring flowering plants like spiderwort and late flowering plants to sustain the multiple flights of butterflies. The spectrum of the canopy for Karner blues must range from zero or open, to 70 percent coverage. Male butterflies like the open while females require shade to lay their eggs. The correct canopy also helps protect against the heavy rain events we are beginning to experience more frequently with climate change.
Graduate students under the supervision of monarch expert, Dr. Karen Oberhauser, Professor, Department of Fisheries, Wildlife and Conservation Biology at the University of Minnesota, will be responsible for the research and monitoring connected to all phases of the project.
That monitoring will include helping to determine specific areas from which to collect eggs so as not to impact the health of the existing populations of Karner blues in Crex Meadows and Fish Lake. Some of the money from the grant is designated to be used to improve habitat for the butterflies and includes prescribed burns and chemical treatments to combat the growth of brush and species that would choke out the lupine and other valuable flowering plants. Eggs that might normally be lost in a burn or chemical treatment can be targeted for collection.
Phase three of the project may be the most ambitious, to restore and connect enough habitat to reintroduce Karner blue butterflies to their historic range. That range traditionally ran in a giant Nike-like swoosh from Ontario Canada southwest down through Grantsburg and the Crex Meadows, Fish Lake Wildlife areas, down along the both sides of the St. Croix River through Polk and St. Croix counties, and east toward Menomonie. At one time, the range of the Karner blue butterfly extended as far south as the Indiana Dunes State Park, but hotter, dryer conditions have pushed populations further north.
A cooperative agreement between the USFWS and SCRA will enable Executive Director, Deb Ryun and her staff to play an integral role in monitoring grasslands both public and private and maintaining habitat over the life of the project until 2020.
"If this program works, and there is no reason to believe it won't, we'll be able to move the butterflies north at much less cost. There is science behind it with all the work the grad students will be doing. And it will be published so down the road people will be able to use and reproduce this technique to move butterflies," said Trosen.
Trosen is equally proud of the wildlife and human communities this grant will nourish.
"Bringing national dollars back to our local area, to work with existing partners and create new partnerships, all to do good things for wildlife, it's tough for us to pass up those opportunities. The many dollars this project will bring to habitat restoration benefits not just the Karner blue butterfly but also the ducks and pheasants, all species that depend on that habitat."