Climate Change Is Destroying Monarch Butterflies’ Winter Habitat

every year, in In early November, one of the world’s most impressive natural wonders took place in the Mexican state of Michoacán. Hundreds of millions of migrating monarch butterflies inhabit the forests of the Mexican Monarch Butterfly Biosphere Reserve, about 100 kilometers west of Mexico City. They fly south for eight months, beginning their journey in the northern United States or southern Canada, where they hibernate over the winter before mating in the spring.

After flying more than 4,000 kilometers, the butterflies landed on the Oyamel fir trees in the Ejido El Rosario region, where they gather for weeks to protect themselves from the wind and cold nights . Without these trees, the butterfly would not be able to make it through this tiring journey.

Oyamere fir grows in a very small climate space that is damp and cold. “Its distribution is very limited to the highest mountains in central Mexico,” said Cuauhtémoc Sáenz Romero, a professor at the University of San Nicolás Michoacán in Hidalgo state. Sáenz Romero is the main author of a book recent research The forest is expected to gradually deteriorate and disappear due to climate change, endangering the butterflies.

Sáenz Romero explains that for roosting monarch butterflies, the oyamel canopy acts as a buffer against local temperature and humidity. “During the day, under the shade of oyamel trees, the environment is 5 degrees Celsius cooler than outside. It is a protective measure against high temperatures. At night, the opposite occurs, causing the ambient temperature to rise by 5 degrees Celsius. The density of the canopy also protects against winter rains. “If When the temperature drops below zero, the butterflies’ wings get wet and they freeze. That’s why these trees represent such a special habitat,” Saenz-Romero said.

After emerging from hibernation and mating in central Mexico, the insects fly north to Texas, where they lay their eggs. “Nonetheless, they need energy reserves to return and don’t have to use that energy to fight off the cold in their overwintering grounds,” he explains.

This fine balance of survival can only be provided by the Oyamere fir. However, some models suggest that by 2090, the region’s favorable climate will disappear. Leading an initiative to establish new wintering sites for monarchs red list Threatened species.