Endangered Prairie Butterflies in Manitoba

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Me catching some prairie butterflies in Manitoba (photo by Christa Rigney)


As an undergraduate research assistant at the University of Winnipeg, I began working on a project designed to predict the adult emergence of two endangered prairie butterflies with Dr. Richard Westwood.  Poweshiek and Dakota Skippers have been in decline in recent decades, potentially signalling a wider decline in native prairie habitat integrity.  The best way to quantify population sizes and specific habitat preferences of these two species is to survey adult butterfly populations.  However, the timing of adult flight periods can vary widely from one year to the next and populations are currently restricted to disjunct patches of native prairie, so planning surveys every year is extremely challenging.

Methods and Results:

To give surveyors a better idea of when to start looking for adult butterflies, Richard and I used six years of previously collected survey data together with temperature data from Environment Canada weather stations and on-site soil temperature logger data to develop a degree day model of adult butterfly emergence.  Our model has successfully predicted adult emergence to within +/- 2 days in most years.  We published our results in the Journal of Insect Conservation in 2014 (see Publications and Presentations), and have been using our model to help plan surveys every year from 2012 to the present.

Richard and I, together with Robert Dana (with the Minnesota Department of Natural Resources), are also investigating possible climatic drivers of recent Poweshiek population declines in Manitoba and Minnesota.  Unfortunately, Poweshiek numbers have dropped pretty sharply since the 1980s, but the Minnesota Zoo has been working with the Nature Conservancy of Canada to breed them in captivity and release them back into suitable habitat.