Quantcast

David Suzuki: How to Save the Monarch Butterfly

Insights + Opinion

The monarch butterfly is a wonderful creature with an amazing story. In late summer, monarchs in southern Canada and the northern U.S. take flight, traveling more than 5,000 kilometers to alpine forests in central Mexico. The overwintering butterflies cling to fir trees there in masses so dense that branches bow under their weight.

Monarch butterflies have only one food source: milkweed. Photo credit: Shutterstock

The monarch’s multigenerational journey northward is every bit as remarkable as the epic southern migration. Three or four successive generations fly to breeding grounds, lay eggs and perish. The resulting caterpillars transform into butterflies and then take on the next leg of the trip. Monarchs arriving in Canada in late summer are often fourth or fifth generation descendants of butterflies that flew south the previous year.

What may be the monarch’s most striking quirk is its caterpillars’ reliance on milkweed as its sole food source, a phenomenon called “monophagy.” Milkweed plants contain small traces of cardenolides, bitter chemicals monarchs store in their bodies to discourage predators, which associate the butterflies’ distinctive coloration with bad taste. But relying on a single type of plant for survival is a risky strategy that has put monarchs in grave danger.

In the mid-1990s, the eastern monarch population was more than 1 billion. In winter 2013, the population had dropped by more than 95 percent to 35 million, with a modest increase to 56.5 million this past winter. As University of Guelph postdoctoral research fellow Tyler Flockhart notes, a single severe storm could extinguish the entire monarch population. A 2002 snowstorm wiped out 80 million butterflies. A similar trend has been occurring west of the Rockies, where the western population overwinters in California and migrates as far north as central B.C.

Much of the monarch butterfly decline has been pinned on virtual eradication of its critical food source throughout much of its migration path by profligate use of a glyphosate-based weed killer called Roundup, which corn and soybean crops have been genetically modified to tolerate. Blanketing fields with the herbicide kills plants like milkweed. As a result, several U.S. states in the Midwest—the heart of monarch breeding territory—have lost most of their native milkweed, causing monarch reproductive rates to drop by more than 80 per cent.

A recent study suggests glyphosate is merely the first of a one-two toxic punch from industrial agricultural operations. The second is neonicotinoids, the controversial nicotine-based insecticides that have been identified as a chief culprit in the decline of honeybees, along with a host of birds, bees and butterflies. It appears that even at one part per billion, these chemicals can affect monarch caterpillar development, delivering a potential knockout blow for the imperiled insects.

The good news is that many jurisdictions are catching up with the science. Ontario’s government has proposed regulations to reduce neonicotinoids use by 80 per cent over the next couple of years. In early April, the U.S. Environmental Protection Agency issued a moratorium on new applications to use neonicotinoids. I hope this marks the turning of the toxic tide, but time is running out.

What can you do to help? While government agencies in Mexico, the U.S. and Canada are scrambling to hatch plans to save monarchs, the scientific community has been clear: A lot of milkweed must be planted over the next few years. One great opportunity is the many thousands of kilometers of linear corridors—rail, road and hydro rights-of-way—that run throughout the migratory landscape and can be modified to grow milkweed and other pollinator-friendly plants.

Yards, school grounds and parks are also perfect for butterfly gardens and milkweed patches, and planting milkweed in your backyard or balcony garden is a great way to help. Be sure to call your local garden centre or nursery to ensure they stock native milkweed plants this spring.

Find out more about milkweed and information about how to bring monarchs back from the brink at the David Suzuki Foundation’s Got Milkweed campaign website. You can also donate to support Foundation volunteers planting milkweed in the greater Toronto area.

Planting milkweed may seem small, but the combined actions of thousands of concerned citizens stitching together parks and yards with schools and rights-of-way into a glorious tapestry of butterfly corridors could usher in a new, hopeful era for monarch butterflies.

YOU MIGHT ALSO LIKE

Microbeads: A Sign of Our Plastic Consumer Madness

5 Horrifying Images from the Nepal Earthquake

MIT’s Solar-Powered Desalination Machine Could Help Drought-Stricken Communities

EcoWatch Daily Newsletter

Individual standing in Hurricane Harvey flooding and damage. Jill Carlson / Flickr / CC BY 2.0

By Allegra Kirkland, Jeremy Deaton, Molly Taft, Mina Lee and Josh Landis

Climate change is already here. It's not something that can simply be ignored by cable news or dismissed by sitting U.S. senators in a Twitter joke. Nor is it a fantastical scenario like The Day After Tomorrow or 2012 that starts with a single crack in the Arctic ice shelf or earthquake tearing through Los Angeles, and results, a few weeks or years later, in the end of life on Earth as we know it.

Read More Show Less
A pregnant woman works out in front of the skyline of London. SHansche / iStock / Getty Images Plus

Air pollution particles that a pregnant woman inhales have the potential to travel through the lungs and breach the fetal side of the placenta, indicating that unborn babies are exposed to black carbon from motor vehicles and fuel burning, according to a study published in the journal Nature Communications.

Read More Show Less
Sponsored

Teen activist Greta Thunberg delivered a talking-to to members of Congress Tuesday during a meeting of the Senate Climate Change Task Force after politicians praised her and other youth activists for their efforts and asked their advice on how to fight climate change.

Read More Show Less
Ten feet of water flooded 20 percent of this Minot, North Dakota neighborhood in June 2011. DVIDSHUB / CC BY 2.0

By Jared Brey

When Hurricane Michael tore through the Florida panhandle last October, it killed at least 43 people, caused an estimated $25 billion in damage and destroyed thousands of homes.

Read More Show Less
A protestor holds up her hand covered with fake oil during a demonstration on the U.C. Berkeley campus in May 2010. Justin Sullivan / Getty Images

The University of California system will dump all of its investments from fossil fuels, as the Associated Press reported. The university system controls over $84 billion between its pension fund and its endowment. However, the announcement about its investments is not aimed to please activists.

Read More Show Less
Sponsored
Forest fire continues to blaze in Indonesesia on Sept. 18. WAHYUDI / AFP / Getty Images

Nearly 200 people have been arrested in Indonesia over their possible connections to the massive wildfires raging in the nation's forest, officials said this week.

Read More Show Less

By Ngozi Okonjo-Iweala

World leaders have a formidable task: setting a course to save our future. The extreme weather made more frequent and severe by climate change is here. This spring, devastating cyclones impacted 3 million people in Mozambique, Malawi and Zimbabwe. Record heatwaves are hitting Europe and other regions — this July was the hottest month in modern record globally. Much of India is again suffering severe drought.

Read More Show Less
Covering Climate Now / YouTube screenshot

By Mark Hertsgaard

The United Nations Secretary General says that he is counting on public pressure to compel governments to take much stronger action against what he calls the climate change "emergency."

Read More Show Less