July 16, 2013, 2:57 p.m.
A once-common prairie butterfly is being called a “canary in a coal mine” because of a rapid decline that is prompting researchers from Canada and the United States to try to save it.
The little brown butterflies, known as the Poweshiek skipperling, were once so plentiful that researchers didn’t even bother to count them. Now there are fewer than 200 left in Canada, most of them in Manitoba.
Cary Hamel with the Nature Conservancy of Canada said the butterfly’s rapid decline is a sign that the prairie grass ecosystem is at risk.
“Butterflies are a bit of a canary in a coal mine. They’re really sensitive to changes in weather. They’re sensitive to changes in habitat loss. They’re sensitive to changes in habitat loss. They’re sensitive to invasive species and land management,” Mr. Hamel said.
“The fact that the Poweshiek skipperling and other prairie butterflies are all declining should really have us stand up and take notice that something is going wrong with our native prairies.”
Since the butterfly is primarily found on land owned or managed by the conservancy, the organization is doing all it can to ensure the creature’s survival, Mr. Hamel said. It has partnered with researchers at the University of Winnipeg, the University of Michigan and the Minnesota Zoo to keep the fluttery creature alive.
Richard Westwood, professor of Environmental Science and Studies with the University of Winnipeg, said the Poweshiek Skipperling once would have thrived from Canada all the way down to Texas — just like the original tall grass prairie.
But that habitat has shrunk dramatically.
“The tall grass prairie is probably the most threatened ecosystem in North America. There is only about one per cent of it left,” Prof. Westwood said.
“(The butterfly is) being confined to these very, very small remnants in comparison with the vast areas of prairie that used to exist before.”
Making matters worse, the Poweshiek skipperling is a bit of a “homebody” and can’t travel to a different part of the ecosystem if it is threatened, Prof. Westwood said.
“If you have something catastrophic happen to that particular prairie — it gets farmed or grazed too heavily or wildfire comes along and destroys the habitat or wipes out the species — it’s pretty well finished in that particular area,” he said. “You don’t get movement between these isolated areas.”
Prof. Westwood said researchers are cautiously optimistic the species can be saved with the right mixture of education and intervention. Some farming practices and wildfires that are particularly devastating to the species could be prevented.
As a kind of insurance policy, the Minnesota Zoo has collected eggs from some of the females and will be hatching them in a controlled setting. Erik Runquist, butterfly conservation biologist with the zoo, said the goal is to breed a stable population before eventually reintroducing the insects into the wild.
The butterflies are very vulnerable and have been particularly battered by poor weather this year, Dr. Runquist said. The zoo wants to help kickstart the population by treating the butterflies like any other endangered species, he said.
“If you think of tigers, there are only 3,500 wild tigers in the world. Most of the tigers that are in zoos are part of a managed, co-operative breeding program focused on maintaining large, genetically robust populations.
“We want to do the same thing with the butterflies.”