In 2018-2019, the area occupied by butterflies to hibernate was 6.05 hectares, which tells us that we must continue working to maintain this trend and reinforce protection measures by Mexico, the United States and Canada.”
Jorge Rickards, General Director of WWF Mexico.
Monarch butterflies travel more than 4,000 kilometers to reach their sanctuary in the country, located in the Oyamel forests in Michoacán and the State of Mexico. Along their route through Canada and the United States, they face increasing threats. Climate change, droughts, and forest degradation are just a few obstacles that these travelers have to overcome.
With everything and adversities, today there is good news for Mexico, since the presence of the Monarch butterfly in Mexican overwintering forests increased 35% in the 2021-2022 season, occupying 2.84 hectares (ha) of forest, compared to 2.10 ha. reported the previous season. This is mainly due to the early repopulation of butterflies in the southern United States. According to the annual monitoring report presented this Tuesday by the National Commission of Natural Protected Areas (Conanp) and the WWF-Telmex-Telcel Foundation Alliance, the Monarchs agglutinated in six colonies (2,174 ha) within the Biosphere Reserve Monarch Butterfly and in four outside it (0.661 ha); in total they are located in five colonies in Michoacán and five in the State of Mexico, occupying 2,835 ha.
In contrast, hibernation in 2020 (2.10 ha) represented 26% less compared to the 2.86 hectares of the previous record. This represents a significant achievement because the work of authorities, countries and, above all, of the communities in the core zone of the Monarch butterfly has been arduous and continuous. This area was recognized in 2008 by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as a Natural World Heritage Site that protects 56,259 hectares, including 13,551 of the core area, between Michoacán and the State of Mexico. , where the priority forests where Monarchs hibernate are found.
However, we must not lose sight of the fact that the hibernation habitat of the species was drastically reduced during the 21st century, we practically lost 16.19 hectares. The variation per year has various causes. According to Gloria Tavera Alonso, general director of Conservation for Development, in 1996-1997 there was the largest forest occupation registered, it was 18.19 hectares, then a series of climatic effects significantly reduced the space occupied, thus, for 2003-2004 the occupation was just over 10 hectares. “This was the turning point for the beginning of a more systematic monitoring.”
In 2013-2014 one of the worst crises occurred, when the population decreased by 95% in all the colonies, at that time all lines of action and work were rethought, to increase the population through reproduction and the increase in reproductive habitat, thanks to the reconversion of the use of glyphosates, the increase in milkweed and aclepias, all conducive to the species Danaus plexippus. On the other hand, in the analysis of the core area, a forest degradation of 20.2 hectares was recorded, due to sanitation, drought and mainly clandestine logging.
Jorge Rickards, general director of WWF Mexico, assures that the effort must continue. “In 2018-2019, the area occupied by butterflies to hibernate was 6.05 hectares, which tells us that we must continue working to maintain this trend and reinforce protection measures by Mexico, the United States and Canada. Monarchs are pollinators important and their migratory journey favors the reproduction —with greater diversity— of flowering plants, which benefits other species in natural systems and contributes to the production of food for human consumption in productive systems”.
Scientific and community instrument for measurement
The authorities explain that in order to carry out the systematic monitoring of the forest occupation of the Monarch butterfly, as of December 2021, the 13 hibernation sanctuaries found in the “Monarch Region” were visited twice a month.
When the colonies are found, their location is established with a Garmin® geopositioner and the perimeter of the forest occupied by the lepidoptera is determined from the tree found in the highest part of the slope, for which the course and direction are recorded. distance from consecutive and peripheral trees of the colony.
With them, it was possible to determine that the largest colony (1,187 ha) was registered in the El Rosario ejido (Sierra Campanario sanctuary, Michoacán) and the smallest colony (0.003 ha) was located in the Crescencio Morales ejido (Lomas de Aparicio sanctuary, Michoacán). Michoacán), this is another piece of good news, as the colony reappeared after being last found in 2003-2004. For its part, in the municipality of Atlautla, adjacent to the Iztaccíhuatl-Popocatépetl National Park, there was a presence of butterflies, but a compact colony was not established.
The variation per year has various causes:
- habitat decline
- Degradation
- Climate change, among others.
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