Sightings of Endangered Butterflies in Southern Ontario Electrify Species Reintroduction Efforts


A mottled dusky butterfly was spotted in Ontario’s Pinery Provincial Park this month following a reintroduction effort last year.Handout

A team of Ontario biologists are celebrating a milestone in their attempt to re-establish the Mottled Duskywing – an endangered butterfly species – at a site in southwestern Ontario.

In recent days, the gray and brown speckled butterflies have been spotted in Pinery Provincial Park, northwest London, where a multi-year project to bring the species back is underway.

“We have had 10 sightings so far. It’s very exciting,” said Jessica Linton, project manager for the effort and senior biologist at environmental consulting firm Natural Resource Solutions Inc.

Last summer, Ms Linton and researchers from the University of Guelph in Ontario released adult Mottled Duskywings and deposited pupae and larvae in the park in hopes that some of the insects would do well enough to survive. in the winter.

The first indication that this happened came 11 days ago when a visitor to the park spotted one of the butterflies and reported it on iNaturalist, a citizen science social network that serves as a clearinghouse for species observations. Ms Linton said as soon as she heard about the report, she and her colleagues went to the park and were able to see some of the butterflies for themselves.

Prior to the reintroduction project, the last confirmed sighting of a Mottled Duskywing in the park was in 1992.

The decline of the butterfly, which is listed as endangered and threatened with imminent extinction in Ontario, goes hand in hand with the loss of its natural habitat, described as the oak savannah. It’s a mixed landscape of hardwood forests and grasslands that once covered large swathes of the American Midwest, with pockets in Canada around the Great Lakes.

Pinery Provincial Park, located on the shore of Lake Huron, is one such pocket that was all but erased, beginning in the 1960s when the area was reforested with pine trees and its natural cycle of fire and regrowth has been deleted. Later, an overabundance of white-tailed deer robbed the park of the mottled duskywing’s favorite food, a shrub called New Jersey tea. Since then, park managers have worked to restore native oak savannah habitat, using measures such as controlled burning and deer harvesting by native hunters.

Jeremy Kerr, a professor and ecologist at the University of Ottawa who is not involved in the Mottled Duskywing project, said returning the park to something like its original state was a difficult but crucial step.

“The scene had to be built before the characters could be introduced,” he said.

Ms Linton said even then the butterflies would have no way of getting to the park on their own. The federally funded project was first to collect specimens about 250 kilometers away near Rice Lake, where the Mottled Duskywing still occurs, and raise them in captivity at the Cambridge Butterfly Conservatory west of Toronto.

After testing the methodology on a surrogate species and working with Mottled Duskywing for two years, the team had bred enough butterflies to attempt a reintroduction last summer. Ms Linton said more butterflies would be brought to the park in July to increase their numbers there.

If the effort continues to show promise, she said, the next step would be to try the same approach in a different location on the shore of Lake Erie, where the Nature Conservancy of Canada has returned a plot of former farmland to its original state.

“If we can create new habitat while trying to make do with what we have, that will be a kind of game-changer for the species,” Ms Linton said.

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