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If you live in North America, there’s a good chance you’ve seen a Monarch butterfly, if you haven’t really enjoyed their pit stops in your area. Black and orange beauties are a sure sign of the changing seasons, whether their arrival heralds spring, summer, or fall where you live. With a flutter, flutter, they hover as they glide over our gardens, looking for a sip of nectar or a milkweed leaf on which to lay their eggs.
But these special sightings are becoming rarer as butterfly populations decline. The largest eastern population of butterflies declined by 84 percent from 1996 to 2014, the Reports of the International Union for Conservation of Nature (IUCN)while the smaller western population has declined by nearly 99.9 percent since the 1980s.
Experts from the IUCN, which maintains the IUCN Red List of Threatened Species, officially listed the species as endangered this July. It means that they face a very high risk of extinction in the wild.
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Monarchs have a special migration pattern: it takes them several generations to travel across the continent. In summer, they live in the US and southern Canada, drawing nectar from flowers and laying eggs exclusively on milkweed plants. In winter, they congregate at only a few sites in California and Mexico. It’s in these places that the decline has been most severe, calling the insects endangered: In the winter of 2020-2021, they were only found in about five acres of forest. In California, they only counted 1,914 butterflies.
Monarchs’ biggest threat is logging and loss of habitat in their wintering range. If the specific forests where these butterflies disappear overwinter, so will the monarchs. Add to that the widespread removal of milkweed plants, which are necessary for monarchs to reproduce, throughout their breeding range, thanks especially to improvements in the herbicides farmers use to keep farm fields weed-free. To top it off, with climate change bringing extreme temperatures, droughts and changes in when flowers bloom, it’s no wonder butterflies are in so much trouble.
Monarch’s roost. (Credit: Mike Budd/USFWS)
The IUCN Red List is independent of the endangered species list maintained by the US Fish and Wildlife Service, which offers legal protection to the species under the Endangered Species Act. Although the Red List has no legal backing, it is considered the gold standard for assessing the status of species worldwide.
The new list is important, explains entomologist Anna Walker, because it provides a frame of reference for how threatened a species really is from being lost. “I think it’s really important to put the conservation status of an iconic species like the monarch in a global context,” says Walker. “It gives people a way to contextualize, how concerned should we be?”
Walker, a species survival officer for the New Mexico Bioparks Society, led the monarch assessment. He is a member of the IUCN Species Survival Commission Butterfly and Moth Specialist Group.
How to list an endangered species
To add a new species to the IUCN Red List, conservation biologists like Walker put together a comprehensive report on how much species numbers have declined and how fast, how much of their habitat has been destroyed, what threats remain, what conservation efforts are in progress and more.
“Most of the insect species I’ve looked at just don’t have information, and it’s really frustrating,” he says. “We did a project where we looked at all 132 firefly species in North America, and more than half of them were data deficient, which means we don’t know enough about the species to determine whether or not it’s at risk of extinction. . That’s very common.”
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Fortunately for the monarchs, Walker had plenty of information to compile the report. “There was a lot of data to sort through, because not only is there academic research on it, but it’s also a species that benefits from community science,” she says.
Walker says the most critical data for the assessment was the population counts of the monarchs’ hibernating areas. “Because this butterfly clusters in a small area during the winter, it’s relatively easy to determine how many there are,” she explains. “In addition, the population that spends the winter is smaller, it is when it has the fewest number of individuals and, therefore, it is when it is most vulnerable.”
A Monarch butterfly sips nectar from a New England Aster. (Credit: Greg Thompson/USFWS)
How citizen scientists drive conservation
Walker says her work in conservation would be easier if more people contributed to citizen science projects. “There just aren’t enough researchers, we don’t have enough resources for just scientists to go out and collect all this data,” she says. “There are millions of insects, and we understand very little about most of them.”
Monarch butterflies have been something of an exception due to their popularity. They’re easy to notice and identify, they’re aesthetically pleasing, they’re even easy to raise in classrooms or at home to release into the wild. As for insects, they are incredibly well studied and their decline is well documented.
“It’s very, very important and people can make a big difference,” she says. “And I think the monarch is a good example of that.”
Get Involved: Find citizen science projects helping monarchs near you at ScienceNearMe.org!
For example, monarch tagging programs like the Southwest Monarch Study have led many researchers to understand where specific populations, such as those in Arizona, hibernate. “We definitely have the scientists in the community to thank for much of the understanding we have about migration,” says Walker.
Milkweed observations, which can be submitted through citizen science apps like iNaturalist, can guide restoration efforts (where is milkweed missing?) and tell conservation biologists where important milkweed habitats are found.
Even general butterfly observations are also helpful. For example, the North American Butterfly Association conducts an annual butterfly count, and that data is also useful for monarch conservation. “Even if you’re not looking for monarchs specifically and are just looking for butterflies in general, you can contribute to monarch research,” says Walker.
A future for monarchs
Walker came across some good news while working on the IUCN report. Although monarch numbers remain too low, their decline appears to have at least slowed somewhat. Their summer breeding populations have been more stable of late. Walker suspects that a large part of this is due to milkweed planting efforts. “People are planting milkweed in their gardens and parks, and it looks like this could be making a big difference,” he says.
Do you want to participate? Learn more about citizen science projects and other opportunities to help monarchs at Science Near Me. Science Near Me is a free resource to help you find opportunities to participate in all kinds of science events, projects, and programs near you, in person and online. Your citizen science projects come from partner SciStarter.org, which hosts thousands of citizen science projects on the Internet! Find ways to report monarch sightings, participate in tagging campaigns, raise caterpillars, attend monarch events, and more at ScienceNearMe.org.
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