On September 19, the first monarch butterflies crossed the Rio Grande on their migratory journey to the forests of Michoacán and the State of Mexico, where they protect themselves from the winter hanging from the trees in huge clusters.
The date has drawn the attention of Mexican environmental authorities, because it represents an advance in the traditional migration season, which is in October.
But what has puzzled them the most is a decrease in the number of hectares of forest occupied by butterflies this year, one of the lowest recorded since 2018. Environmentalists are turning their eyes to the extreme temperatures generated by La Niña - a phenomenon in the one that the global temperature drops and that is increasingly exacerbated by climate change— and the deforestation registered in the reserve that is the sanctuary of the butterfly to explain this change in behavior, which increases fears about its preservation.
The monarch butterfly flies 5,000 kilometers from Canada to Mexico to hibernate and reproduce, in what is one of the greatest natural spectacles in the world.
This winter, however, the monarchs have covered just 2.1 hectares of land, a marked reduction compared to the 2018 season, when they occupied more than 6 hectares of forest.
If this trend continues, the authorities fear that it will reach the situation of 2014, when the butterfly colonies decreased by 95%, with only 0.67 hectares occupied.
The disappearance of a flower known as milkweed, a delicacy for the butterflies that have it as one of their main sources of food, the increasingly extreme temperatures in winter and the clearing of the forests where their sanctuary is put at risk the migration of the butterfly and its own survival.
Jorge Rickards, director of the World Wildlife Fund (WWF) in Mexico, reported this Thursday that between 2019 and 2020, 20.2 hectares of forest have been lost in the Butterfly Biosphere Reserve, 13.3 of them due to clandestine logging. , which affects the essential water reserves to guarantee the permanence in the region of the monarch.
"Without a doubt, the issue of soil moisture, the environment, are essential elements for the monarch butterfly," Rickards explained at a press conference.
"To the extent that we allow the degradation of the forest there is less water catchment, with a negative effect for the monarchs."
Gloria Tavera, a biologist with the National Commission for Protected Natural Areas, classifies the phenomenon as "water stress" and assures that this winter entire colonies of butterflies have come down in search of water to the houses of the towns near her sanctuary.
The sanctuary of the monarch, which is shared between the States of Michoacán and Mexico, is threatened by the boom in avocado cultivation, a fruit that is in great demand in the United States and of which Michoacán is the world's leading producer.
Many farmers, overwhelmed by poverty, cut down the pine forests to cultivate the so-called green gold.
But mafias are also involved in the destruction of the forest cover that develop an entire illegal economy that includes loggers, clandestine centers for the processing of forest resources and transporters, whose juicy business is to disguise raw materials, mainly pine wood, oak. and oyamel.
“It is difficult to establish the precise cause of the increase in logging [during the 2019-2020 period].
However, the change in land use is the issue that must be stopped with greater support for all communities.
It is necessary to increase support programs for sustainable productive projects ”, says Rickards, from WWF.
The loss of the forest is compounded by the extreme temperatures that are recorded in North America as a result of climate change.
This year the La Niña phenomenon has occurred, which has the potential to generate a harsher winter.
"In 150 years we had not seen those low temperatures in Texas and since 1962 there have not been such extreme cold in Tamaulipas," says Gloria Tavera.
This biologist says that frosts degrade forests and affect flower fields where monarch butterflies feed and reproduce, which is of particular concern to environmentalists.
"There hasn't been much mating movement in the colonies, and in spring the butterflies are ready to return [to Canada]," he explains.
"Let's hope that temperatures will rise in the following season to keep this migratory phenomenon alive," says the biologist.
If the cold becomes extreme again, the monarch will lose her warm Mexican refuge and this would end her dazzling migratory phenomenon.
