Monarch butterflies are now an endangered species


A beloved visitor to the Summer Gardens is officially an endangered species.

The migratory monarch butterfly, the iconic subspecies common to North America, was declared endangered today by the International Union for Conservation of Nature (IUCN), the world’s leading authority on state of biological diversity.

The butterfly, known for its biannual 2,500-mile journey across the continent between its summer and winter zones, has declined 23 to 72 percent over the past 10 years, according to the IUCN.

Although the monarch has long been considered threatened, its listing on the IUCN Red List – the inventory of species conservation status – marks the first time it has been officially declared to be in danger of extinction.

“It’s hard for people to imagine that something that appears in their backyard is under threat,” says Anna Walker, who led the monarch butterfly assessment. She is a member of the IUCN Species Survival Commission’s Butterfly and Moth Specialist Group and Species Survival Officer at the New Mexico BioPark Society.

The threat to monarchs comes from a combination of factors. Habitat destruction over decades in the wintering grounds of migratory monarchs has taken its toll. The impact is felt by both the western population, which is found west of the Rocky Mountains and winters on the California coast, and the eastern population, which is found in the eastern United States and Canada and winters in the fir forests of Mexico. In summer habitats, pesticides used in agriculture have killed monarchs and also milkweed, the plant in which they lay their larvae. Climate change is also a growing threat, as severe weather events such as hurricanes and drought become more frequent along the southern migration routes of butterflies. .

The population of less-studied and more at-risk western monarchs has fallen by 99.9% in recent decades, from around 10 million in the 1980s to just 1,914 in 2021, according to the IUCN. The eastern population decreased by 84% between 1996 and 2014.

Only 1% of insect species have been assessed by the IUCN. It is therefore important to have the monarch on the list. Listing can be a great tool for communicating to the public and to world authorities about the urgent need to conserve the butterfly, Walker says.

Bad news for sturgeons, good news for tigers

The IUCN also announced today that all sturgeon species – 26 in total – are now threatened with extinction, and 17 of them are critically endangered. One species, the Yangtze sturgeon, is now extinct in the wild.

Sturgeons are considered living fossils because the fish remain largely unchanged from the earliest fossil records. They date back 145 million years and coexisted with the dinosaurs.

For centuries, sturgeons have been overexploited for their meat and caviar. While all sturgeon species are protected by international trade law, more than half continue to be poached and sold as delicacies. According to the IUCN, a stricter crackdown on illegal fishing and sales is essential to stop the trade.

The IUCN announcement offered good news for some species, including the tiger. New data indicates that there are between 3,726 and 5,578 tigers living in the wild, 40% more than the population estimated in 2015. This improvement comes mainly from improvements in monitoring as opposed to a baby – boom of the tigers. But the IUCN says it is nevertheless a good sign that the tigers, although still threatened, are stable and potentially on the increase, thanks to conservation efforts. (Read about a dense Indian forest where tigers thrive.)

Hope for Monarchs

For the new assessment, Walker and her colleagues analyzed a huge amount of data on monarch numbers from a variety of sources, which helped reconcile some differences, she says.

A recent and controversial study based on citizen science data from summer nesting sites. suggests that monarch butterflies may be increasing in some places in the United States. It’s the winter data, however, that is most telling, says Walker: “Even if populations rebound in some places during the summer, if overwintering populations continue to decline – or even remain stable – they remain extremely low.”

Last winter, however, offered some hope. A scientific community count of butterflies at 283 winter nesting sites in California, led by the Xerces Society for Invertebrate Conservation, saw a rebound for the western monarch butterfly: 250,000 butterflies were recorded, up from 1,914 in 2021. The winter counts are the most reliable way. to monitor populations, says Walker, because nesting sites are clustered in a small area, making counts more reliable.

Still, “when you think there were 3 to 10 million butterflies in winter in the 1980s, and now there are 250,000,” she says, the overall trend in winter data is not not promising.

“We thought it would be good to take all the data – some of it is contradictory – and put it into this overall context. This way, we use a standardized process” that is not influenced by political or social factors, she says. (Read why the United States refused to list the monarch butterfly under the Endangered Species Act in 2020)

There is also hope for the resilience of monarchs, says Walker. Insects reproduce quickly “so this gives a great opportunity: if we reduce some threats, the butterfly can do the rest of the work,” she says.

“We’re kind of at this critical window where climate change is going to start having a bigger and bigger impact on species,” she says. Increasing the population now may therefore be essential to setting the butterflies up for success.

The fact that migratory monarchs are barnyard insects means that everyone can participate. In North America, planting native milkweed (not tropical, which stays evergreen and may tempt monarchs to choose not to migrate for the winter) is a great way to help them thrive. , she says.

Since “there’s still so much we don’t know” about monarchs, getting involved in community science programs that track and protect butterflies locally is another way to help, she says.

“Unfortunately, this wouldn’t be the first time that a common and widespread species has been able to decline very rapidly and disappear from the face of the Earth,” says Walker – a reference to the passenger pigeon, a once ubiquitous bird that has gone extinct. in the wild in 1914.

But unlike a century ago, today there is an unprecedented awareness of the biodiversity crisis. And it can spur action on behalf of endangered species, Walker says, if people care enough: “I think the monarch has the power to do that.”


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