The Sundarban
Photographs byJaime Rojo
ByMarti Trgovich
The flapping wings of millions of monarch butterflies at the Monarch Butterfly Biosphere Reserve in Michoacán, Mexico, create a fluttering sound that Alfonso Alonso describes as “magical.”
The butterflies migrate from the northern United States and southern Canada each year moral in time for Día de los Muertos on November 1 and 2, when celebrations in many parts of Mexico honor deceased ancestors.
The serendipitous timing may have resulted in the assumption that a monarch butterfly who visits you represents the soul of a departed appreciated one. “For the local tradition, it’s miles just like the souls of their of us that have passed away are coming back to reunite with them,” says Alonso, a conservation biologist with the Smithsonian’s National Zoo and Conservation Biology Institute, who’s been finding out monarch butterflies for about 30 years. The orange wings also resemble the shade of the cempasúchil flower, commonly aged at altars and funerals in Michoacán. “[The reserve is] a spiritual trip.”
However a unusual survey, revealed lately in Acta Oecologica, suggests that this annual overwintering monarch “hotspot,” which is also a UNESCO World Heritage residing, can be threatened by a staple of Mexican delicacies and American brunches: the ever-popular avocado.
“The expansion of avocado is a unusual threat that wasn’t there 20 years ago,” says survey co-author Diego R. Pérez Salicrup, an ecologist at the Universidad Nacional Autónoma de México who has studied the monarch populations at the reserve for 15 years. Mexico exports more than 2.4 billion pounds of avocados to the U.S. each year, and nearly 90 percent are from the region around the biosphere. “It’s imposing a unusual tension on the monarchs.”
A butterfly ‘hotspot’ at threat
LIMITED TIME OFFER
Millions of butterflies resolve in the sacred fir trees, 10,000 ft above sea level, at the reserve each autumn. Heading downhill, conifer and pine-oak forests separate the biosphere reserve from the avocado plantations below.
The survey looked at avocado expansion between 2006 and 2024 and modeled what future avocado production may presumably survey like based on diversified climate fashions. The findings counsel that by 2050, one-third of cultivable areas in the lowlands inaugurate air the biosphere reserve will no longer be suitable for avocado production, probably pushing avocado plants to greater elevations.
That’s a mountainous grief for the monarchs. Even the expansion of avocado production into the pine-oak forest—moral beneath the monarchs’ perches on sacred fir trees, also known as oyamel trees—can be dangerous for the monarchs because whereas they count on fat stores for many of the iciness, they also want nectar that’s available in the forests below. And pesticides on the avocado plants would also harm butterflies and other pollinators, which is ultimately bad for the avocados, too.
Ever expanding avocado plantations approach the foothills of Cerro Pelón, a volcanic peak inner the butterfly reserve in Michoacán, Mexico.
“Avocado production is dependent on pollinators,” says survey co-author Eduardo Sáenz, an environmental scientist at the Universidad Nacional Autónoma de México who has been finding out the butterflies for 15 years. “So or not it’s very contradictory how the avocado production is threatening local pollinators, along side monarch butterflies.”
The location of the butterfly migration “hotspot”—80 miles west of Mexico City, in forested mountains—was came across only 50 years ago. The Monarch Butterfly Biosphere Reserve commemorates its 25th anniversary this year; it obtained its name in 2000 when the Mexican executive expanded its stable area to more than 138,000 acres.
The lowest level of forest, the pine-oak forest, is currently “at once impacted” by avocado expansion, Sáenz says. However the survey authors also mapped out diversified climate change scenarios, and each forecasted avocado production encroaching upon the stable butterfly territory in the mountains. “Within the worst-case scenario, warmer climates are going to reach greater elevations faster, and that’s going to be easier for potential producers to flip these forests into avocado plantations,” Pérez Salicrup says.
In that scenario, the microclimate of the forest would turn out to be a more tolerable condition for an avocado orchard. “Suitable areas for avocado production will reach contemporary elevations the place monarch butterfly colonies are,” says Sáenz, who has a deeply personal relationship with the biosphere. His father was a forest engineer who would convey Sáenz to the biosphere when he was a child. “Literally, I aged to play with my toys under monarchs flying around,” he says.
Scientists don’t know why monarch butterflies chose this area in particular to roost, but Alonso, who was not inquisitive about the unusual survey, suspects the microclimate of the mountains attracts them. The chilly weather allows the butterflies to conserve energy sources for the iciness.
“We aged to have certain temperature and humidity at 1,500 meters above sea level. Now you may have these same temperatures and humidity worthy greater, maybe 2,000 meters elevation,” adds Pérez Salicrup. “We have to understand that this very surprising change and tantalizing climate may eventually facilitate the expansion of avocados greater up into the mountains each year.”
Streaked with sunlight and crowded collectively for warmth in iciness, monarch butterflies blanket fir trees El Rosario Sanctuary in the Monarch Butterfly Biosphere Reserve of Michoacan, Mexico.
Inexperienced gold
You May Also Treasure
Whereas the core of the Monarch Butterfly Biosphere Reserve is stable, along side the buffer zone to a lesser extent, the fringes are not—and enforcement can typically be iffy, especially with the advent of cartels dipping into “green gold.” A 2025 paper notes that organized crime gadgets that relied on heroin for earnings lost money after fentanyl came onto the scene in 2014; many of these cartels diverse, along side “extortion and theft in licit industries, such as the avocado sector.”
In fact, the “expanding criminal networks” and violence in the region have been
