Canadian/U.S. researchers concerned that southern Manitoba's lack of snow spells bad news for endangered butterfly
With as little as six centimetres of snowpack at the Manitoba Tall Grass Prairie Preserve, scientists with the Nature Conservancy of Canada along with Minnesota researchers are concerned for the well-being of the already endangered, poweshiek skipperling.
The poweshiek skipperling is a critically imperilled butterfly that in Canada can only be found in the Vita area of southeastern Manitoba.
Listed as endangered in both Canada and the United States, the species has been drastically declining everywhere it occurs. Although the cause of the decline is not fully understood, a team of Canadian and American conservation experts are working diligently to find out.
In 2015, only 36 adults were observed in Canada, and less than 500 world-wide, despite being formerly widespread and predictably common across the nothern Great Plains.
Although basic life history information is currently lacking, and the exact mechanism by which the caterpillars survive winter is unknown, researchers are concerned that low-snow conditions may negatively impact poweshiek skipperling survival.
Snow is an excellent insulator that would normally help protect hibernating caterpillars from Manitoba's typically cold winter temperatures.
Minnesota Zoo butterfly conservation expert Dr. Erik Runquist also notes that recent above-freezing temperatures and lack of snow could also drive at least three other sources of mortality:
- the warmth could cause caterpillars to wake prematurely and burn fat reserves that they need to survive until spring;
- warm temperatures could allow for mold to develop in the leaf litter that the caterpillars depend on for winter shelter; and
- caterpillars could dry out due to exposure to dry winter air. Poweshiek skipperling caterpillars hibernate at ground level, where humidity is higher due to snow cover.
The Nature Conservancy of Canada is hosting a meeting of Canadian and U.S. poweshiek skipperling conservation experts next month. Raising awareness of this small, prairie species, now much rarer than the giant panda, could be key to its survival.
In the past, tall-grass prairie stretched across millions of hectares, and the loss of a single poweshiek skipperling location due to exceptional weather or some other factor would not have been cause for concern - individuals would presumably recolonize sites.
"Given the rapid decline of the species across its entire global range, Manitoba's poweshiek skipperlings now lie several hundred kilometres from the nearest populations in the U.S. We are in a race against time to understand the cause of this species' decline," said Cary Hamel, Manitoba Science Manager with the Nature Conservancy of Canada.
People are urged to contact the Nature Conservancy of Canada if they would like more information on the poweshiek skipperling and what they can do to help.
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