Three years ago, the eastern monarch butterfly population plummeted to 35 million, a drop of more than 95 per cent since the 1990s. More than a billion milkweed plants, which monarchs depend on for survival, had been lost throughout the migratory range — from Mexico to Canada.
Monarchs, like bees, are pollinators that we depend on for much of our food supply. Therefore, their survival impacts us all. We needed more milkweed in the ground, quickly. But many provinces and states listed the plant as noxious, and few nurseries and garden centres carried it.
A lot has changed in three years. The David Suzuki Foundation launched its #gotmilkweed campaign in April 2013 to encourage Toronto residents to plant milkweed in yards and on balconies. Foundation volunteers, called Homegrown Park Rangers, also planted milkweed in local parks and schoolyards. The Ontario government pulled the plant from its naughty list and media stories about the monarchs’ plight took flight.
By winter 2015, the #gotmilkweed campaign had inspired more than 10,000 milkweed plantings in Toronto, with another 11,000 people across the country pledging to help monarchs via the Monarch Manifesto. Last month, the 2016 #gotmilkweed campaign launched, offering milkweed plants in Toronto and Montreal and seed packets for the rest of the country.
How are monarchs doing? Mexican authorities estimated the population that survived the epic 5,000-kilometre journey from the north last fall was three-and-a-half times greater than the year before. Then the weather turned. The worst winter storm in more than 30 years hit the mountainous forest where eastern monarchs overwinter, killing as many as 11 million.
Severe weather is a major threat to monarchs. Near eradication of milkweed along parts of their migratory route is an even more pressing concern. Milkweed has long been found in roadsides, ditches, medians, meadows and fields. But sprawling development coupled with a dramatic increase in use of the herbicide glyphosate (Roundup) has killed tens of millions of the plants.
Since last fall, the David Suzuki Foundation has worked with University of Guelph conservation biologist Tyler Flockhart to assess how to manage linear infrastructure corridors (transmission lines, railways and highways) as potential “butterflyways.” We hope the results will help establish best practices and make an economic case for boosting milkweed and monarchs throughout North American corridors.
Many cities are aiming to make space for bees and butterflies, but the City of Markham wants to become one of the most monarch-friendly municipalities on the continent. This winter, the Ontario city committed to creating the world’s first municipal milkweed nursery, in partnership with the David Suzuki Foundation. It recently became the first Canadian city to sign a mayoral monarch pledge and has started posting “butterfly parking signs” in city parks.
Although milkweed is spreading and monarch numbers have bounced back from historic lows, the population remains more than 80 per cent lower than 20 years ago. This summer, the great-grandkids of butterflies we welcomed last year will return to Canada. I encourage you to continue bringing them home, one milkweed plant at a time.
