Another Wisconsin Butterfly Will Be Added to the Federal Endangered Species List
The Poweshiek skipperling butterfly will be added to the federal endangered species list. That will make for 10 butterflies on the list.
By Lee Bergquist of the Milwaukee Journal Sentinel, Nov. 23, 2014
Experts thought the endangered Poweshiekskipperling would disappear in places like Wisconsin but survive in historic strongholds of western Minnesota, Iowa and the Dakotas.
Just the opposite happened.
Wisconsin is one of the last remaining places where the little brown butterfly can be found. But even here it lives a tenuous existence.
One — maybe two — sites in Wisconsin are inhabited by the prairie butterfly. It is also found in Oakland County, Mich., and one location in Manitoba.
All are on the periphery of the native range of a butterfly named for a Fox Indian chief. The U.S. Fish and Wildlife Service estimates that 90% of the butterfly’s population in nearby states has been wiped out.
“The Poweshiek skipperling is currently in danger of extinction throughout its entire range,” the agency said last month in announcing it would be listed as a federal endangered species. The protections go into effect this week.
The state listed the species in 1989. Both the state and federal listings prevent private landowners from destroying the insect. In Wisconsin’s case, the Poweshiek (pronounced pow-a-sheek) is believed today to inhabit only public-owned land.
“It’s been a very dramatic decline, and the frustrating thing is that I don’t think that anyone really knows what caused it,” said Owen Boyle, section chief of species management at the Department of Natural Resources.
Susan Borkin of the Milwaukee Public Museum is a local expert on the Poweshiek. She could not find the butterfly in Scuppernong Prairie State Natural Area in Waukesha County in 2013 and 2014.
In 2011, she counted 63 a day during peak flight periods on 20 acres of butterfly habitat.
In the spring of 2012, the DNR conducted prescribed burns of Poweshiek habitat at Scuppernong overBorkin’s objections. She found 45 on peak days that summer.
Based on her counts going back to the early 1990s, Scuppernong had more Poweshieks than any place in the state.
Then after 2012, she found nothing.
The only known sighting in 2014 came from independent researchers Scott and Ann Swengel of Baraboo, who found four last summer in Green Lake County in the Puchyan Prairie State Natural Area.
The conversion of tall grass and mixed-grass prairies to farming across the Midwest, beginning in 1830, was probably the biggest factor, according to the Fish and Wildlife Service.
But this wouldn’t account for the large-scale decline in the last 10 or 15 years.
“It was not the classic extinction due to ‘destruction of habitat’ for most of the sites,” said Borkin, curator of invertebrate zoology at the museum who has studied the butterfly since the early 1990s.
“It was really surprising how quickly they went out. It caught us all a little by surprise.”
Other possibilities: Borkin said that it could have been the introduction of new pesticides, extreme weather changes such as drought, heat waves, bitterly cold winter or flooding, or a combination of factors.
The Fish and Wildlife Service says the restorative powers of natural fire activity, which has been lacking on many prairies, may have hurt the species by harming the grasses. However, the Swengels, who have studied the butterfly across the Midwest, believe the benefits of fire for the Poweshiek are overblown.
And then there is the Poweshiek itself. Unlike the monarch butterfly, whose populations are also plummeting, the Poweshiek is not capable of long migrations.
It pretty well lives in one spot, regardless of changes in local habitat. Rapid, erratic fliers, they live in their butterfly stage for no more than a week. It can fly about a mile, according to the Fish and Wildlife Service.
In the winter, in a larval form, it clings to a blade of grass and is guarded by antifreeze-type protection in its body.
Borkin opposed the DNR’s decision to conduct a burn at Scuppernong on about 20% of the butterfly’s habitat.
In a July 2011 letter to the DNR, she recommended against burning the prairie, “primarily because we don’t know what’s causing the wide-range species decline, this is the only population in WI that can be considered reasonably viable…”
She also said the Poweshiek is “well known to have a negative response to fire.”
In spring of 2012, shortly before the burn, a letter from the agency’s Bureau of Endangered Resources to Borkin and the Fish and Wildlife Service said the agency was going ahead.
The prairie hadn’t been burned in 15 years and only a portion of the butterfly’s habitat would be affected, the agency said.
Also, the property contained the prairie white-fringed orchid, a federal threatened species that would benefit from fire since it is “profoundly shade-sensitive in critical life stages,” an agency official wrote. Burning would remove woody debris that crowds out the orchid.
“I’d argue that we acted very responsibly,” Boyle said. “A lot of what the DNR has to do is balance the needs of many species.”
Both Borkin and the Swengels didn’t blame the DNR for the disappearance of Poweshiek at Scupperong.
“We are disappointed,” said Scott Swengel. “But we realize we don’t control everything — it’s not all about the butterflies.”
The summer of 2012 was extremely hot and dry. That year, Milwaukee set a record as being the warmest on record. The following spring was unseasonably wet.
“Weather played a huge role in knocking out the populations,” Borkin said. “It was a combination of factors that worked against this species.”
What happens if the Poweshiek becomes extinct?
“The Poweshiek is insignificant in the bigger picture,” Ann Swengel said in an email.
“But it’s a huge warning that we don’t understand nature as well as we think we do.”