Dinah Robinson
The numbers are in and the news is not good for monarch butterflies. A shocking decrease of 59 percent in the eastern monarch population was reported by the annual WWF survey for the 2023-2024 winter season.
The forest area occupied by the overwintering monarchs was down to 2.2 acres from the previous 5.5 acres. This is the second smallest overwintering population since monitoring began in 1993.
The migratory monarchs are split into two populations which are separated by the Rocky Mountains. Eastern monarchs overwinter in Mexico and the western population migrates to Southern California. The number of western monarchs overwintering in California dropped by 30 percent this past winter, according to a statement from the Xerces Society.
There is little meaningful protection for migratory monarch butterflies and what does exist is inconsistent. In Canada, the federal government lists them as a species of “special concern” under the federal Species at Risk Act. The United States Fish and Wildlife Service lists monarchs as a “candidate species” for inclusion on the list of endangered or threatened wildlife. Their overwintering habitat in Mexico is also under threat of logging.
What is causing the collapse?
The main driver of the steep decline is the scarcity of milkweed, the exclusive source of food for the monarch caterpillars. There are several root causes of this habitat loss.
Extreme weather, farming practices, use of GMOs and pesticides (e.g., glyphosate), and development in urban areas that eliminates greenspace are the main reasons. Habitat fragmentation is another key component. Butterflies need connected corridors to support frequent stops to feed and lay eggs.
What’s at stake?
CBC Radio recently interviewed Greg Mitchell, research scientist with Environment and Climate Change Canada, based at Carleton University’s Wildlife Research Centre, and the Canadian lead for the Tri-National Monarch Science Partnership.
He had just returned from his third visit to the same site in the central Mexican forest where a colony of monarchs roost in winter. On his first visit, in 2019, he said, there were “millions of butterflies hanging off the fir trees. The branches are bending, they’re drooping, there’s so many butterflies hanging off them.” This year, his impression was very different. His colleague described it as an “empty cathedral,” and Mitchell said, “the forest was beautiful but there weren’t any butterflies.”
According to population viability analysis, the probability is growing that migratory monarchs will go extinct unless there is a dramatic population turnaround.
“If we don’t start acting now, based on the research, we’re at risk of not seeing very many monarchs in Canada, going forward,” Mitchell stated. He’s still optimistic and encourages everyone to plant lots of milkweed and native nectar flowers to aid in the recovery.
Planting for butterflies
Monarchs migrate up to 4,000 km. They therefore rely on thousands of communities across Canada, the U.S., and Mexico on their trips each year. The monarch lays eggs as she travels north to Canada in the spring. The caterpillars voraciously munch on milkweed before they metamorphose into butterflies. Once born, the trip north continues. There are 4-5 generations born every year and most survive just 2-6 weeks. The last generation born in the late summer must complete the entire flight back to Mexico and survive 6-9 months until spring.
Milkweed is the monarch’s host plant. It is the only food that the caterpillars can consume. Several species of milkweed are native to Ontario; swamp milkweed, butterfly weed, common milkweed, and the less common poke milkweed that’s good in shade gardens. Having a variety of species can support pollinators for longer, as they flower at slightly different times from June to September.
Host plants are critical on the flight north and during the summer months when caterpillars are growing. Nectar plants are important throughout the year to supply fuel for the adult butterflies and they are critical in the fall, when the last generation heads south.
Butterflies prefer flowers with flat surfaces or tight clusters of flowers because they need to rest while they drink nectar. Some good options are coneflowers, goldenrods, black-eyed susans, and asters (host plant for the Pearly Crescent and the Silvery Checkerspot Butterfly caterpillars).
Seeds of hope
In Centretown, gardening group representatives and individuals are collaborating to create a pollinator pathway connecting parks and neighbourhood gardens in a way that best supports native pollinators. Small bees, butterflies and moths can only travel short distances before they need to refuel. It’s important to have a series of pollinator gardens that create a connected corridor, from one buffet of flowers to the next – little islands of beautiful plants for humans and food for pollinators.
We’ve already been busy locating plantable spaces, collecting seeds, and identifying community partners and volunteers. We want to create a Pollinator Pathway connecting Dundonald Park gardens via the Frank Street Bee Butterfly Garden to the St. Luke’s Pollinator Garden.
Many communities across Canada are participating in the Butterflyway project, initiated by the David Suzuki Foundation in 2017. The foundation has trained over 1,400 Butterflyway Rangers in hundreds of communities across Canada. The Rangers act are team leaders who connect with neighbours to create pollinator gardens.
Ecology Ottawa is also running the Rewilding Ottawa! Project as part of its biodiversity campaign. They’ve helped create pollinator gardens in three locations across the city. They are trying to educate and inspire Ottawa residents to plant gardens for native pollinators everywhere they can. They have also created a map to track the progress.
Even Canada Post has got the buzz, with its annual stamp release featuring environmentally important native wildflowers including Butterfly Milkweed.
Helping the Pollinator Pathway project
If you want to participate in the Centretown Pollinator Pathway project, there are many ways you can help. We’re looking for volunteers to assist with
- identifying plantable spaces,
- planting seeds and flowers,
- maintaining the new plants by watering and weeding,
- adding pollinator gardens and plantable spaces to a mapping tool, encouraging residents to plant pollinator gardens in front, side, and backyards, and on balconies, porches and rooftops.
Contact fbgardener@prontonmail.com or dinah.robinson.bee@gmail.com to express your interest.
Let’s continue to make Centretown a beautiful place for pollinators and people.