Butterflies that once numbered in the millions have virtually disappeared from Upper Midwest prairies

Erik Runquist saw it for a moment, then it was gone. Walking a tract of Nature Conservancy-owned prairie outside Moorhead, Runquist caught a glimpse of a Dakota skipper, a thumbnail-sized, orange and brown butterfly. It perched atop a coneflower before disappearing into the prairie grass. "Skippers are evasive. You may get only a few seconds to be able to find it before it zips off the coneflower, especially if it's a windy day," said Runquist, the Minnesota Zoo's butterfly conservation biologist. "Once they get in flight, it's almost impossible to find them again. "Fifteen years ago or so, it wasn't so hard to spot a Dakota skipper in Minnesota. But something's changed. Butterflies that once numbered in the millions have virtually disappeared from Upper Midwest prairies.
Another once-abundant butterfly, the Poweshiek skipperling, has also vanished in that time. There hasn't been a sighting here since 2008. It's on the federal endangered species list.

Runquist and other scientists aren't sure what's happening, but they worry the butterflies' disappearance is an ecological warning shot, a sign of a larger environmental problem on the prairie.

"Butterflies are tremendously sensitive to small changes in environmental conditions," he said. "They've alerted our attention that, yeah, there are probably some pretty significant problems on our prairies that we weren't necessarily tuned to."

Prairie butterfly populations naturally declined as Minnesota prairies were turned to farmland over the past century, but their dramatic decline in the past 20 years has scientists puzzled.

"We don't have a cadaver to do post-mortem on," said Robert Dana, a Minnesota Department of Natural Resources entomologist who searches for Poweshiek skipperlings and Dakota skippers at sites across the state every year.

Prairie butterflies began to disappear rapidly in the early 2000s, despite efforts to preserve and restore prairies, he said. "It's very disconcerting to discover that after saving so many prairies, we are not yet on secure ground with the insects."
Source: MPR News, July 12th, 2016
http://www.mprnews.org/story/2016/07/12/minnesota-prairie-butterflies-d…