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She is the queen of butterflies. The most iconic and traveling of them all. The migratory monarch butterfly (Danaus plexippus plexippus) is the first in the collective imagination, with gorgeous orange wings and a tabby pattern that terrifies its predators. But what makes it most famous is the journey the insect makes, barely 0.4 grams, from the United States and Canada to Mexico. The dangers are endless on these 4,000 kilometers. For several years, climate change has affected its fluttering. Although the population has increased slightly to 335,479 specimens, according to the Western Monarch’s 26th annual Thanksgiving Census, conducted by the Xerces Society in California, experts are sounding the alarm about the threats threatening the habitats that pass through.
The migration of the butterfly in the Mexican forests.
This number represents an increase from last year’s total (in which 247,237 were counted), but falls short of the five-year target of an annual average of 500,000 monarchs needed to restore the species included on the Red List of Threatened Species is the endangered category (there are only two others above it: Critically Endangered and Extinct).
“The results of this census are cause for celebration,” Emma Pelton, a conservation biologist at the Xerces Society, said in a statement. “A second straight year of relatively positive numbers gives us hope that there is still time to save your migration. But we know we still have a long way to go to catch up and with recent storms hitting the area it means we’ll start spring with a lot less than that total.
The population of the migratory monarch butterfly has declined by 22% to 72% over the past decade, the International Union for Conservation of Nature (IUCN) warns. Rebeca Quiñonez-Piñón, Monarch Recovery Strategist for the National Wildlife Federation, is even more specific: “Two years ago, that number was down almost 99%. There were only 1,914 copies. There was great concern about such an alarming trend. We figured it wasn’t going to arrive anyway.” In 1997, there were more than 1.2 million of these insects.
Gonzalo Andrade, professor and director of the Institute of Natural Sciences at the National University of Colombia, sees the first effects of climate change in this way 15 years ago. And while he describes how resilient the butterfly itself is, he points out that the destruction of their ecosystems is making it difficult for them to survive. “When torrential rains hit, more snow falls than estimated, heat waves hit… All of this changes the conditions the butterfly needs. It has nowhere to breed and nowhere to hibernate.”
According to the Xerces Society, extreme weather that caused flooding in California damaged the base of the trees that monarchs use to congregate in winter. They broke from their roots and forced them to move to other areas in search of a new haven.
For Quiñonez-Piñón, in addition to habitat destruction that impedes access to breeding grounds or the nectar needed, overuse of pesticides was also key to the loss of these insects. In Mexico, one of the main threats to the species is illegal logging, which is decimating the trees where they overwinter. In fact, the Monarch Butterfly Biosphere Reserve reported a forest cover loss due to clandestine logging of 13.9 hectares last year, up from 13.3 hectares in 2021.
Experts therefore agree that efforts must be concentrated on preserving ecosystems. Quiñonez-Piñón celebrates projects like the Recovering America’s Wildlife Act and the Monarch Act 2021 that promote restoration and mitigation in transit areas. “We cannot slack off on legislation,” he says.
Citizens also have “duties”. “One of the most important points is awareness,” he explains. “Many of the wintering grounds in Canada are on private sites, and individuals need to come on board.” Also, encourage responsible gardening by neighbors by planting native milkweed and nectar plants, necessary for monarch caterpillars and adults. If they disappear, he warns, “it’s everyone’s loss.”