The populations of monarch butterflies in their winter habitats in Mexico have witnessed a dramatic decrease this year, showing a 59% reduction from prior counts. This significant drop to the second-lowest figure since records began is attributed to factors such as elevated temperatures, prolonged dry spells, and loss of natural habitats.
Monarch butterflies undertake a remarkable annual migration across North America, traveling from Canada and the United States to their wintering grounds in Mexico, a journey that no single butterfly completes in its entirety.
The methodology for the yearly evaluation of monarch populations involves measuring the total area occupied by the butterflies as they congregate on tree branches in the pine and fir forests located to the west of Mexico City. These forests are crucial for the monarchs that migrate from the eastern regions of the Rocky Mountains. This year, reports from Mexico’s Commission for National Protected Areas indicate that the butterflies occupied merely 2.2 acres (0.9 hectares), a stark decrease from the 5.4 acres (2.21 hectares) documented last year. The record low was in 2013, with an area of 1.65 acres (0.67 hectares).
The decline is largely blamed on the adverse impacts of climate change, including rising temperatures and drought conditions, which threaten the butterflies’ migration cycle. Gloria Tavera, the conservation director of the commission, highlighted the significant role of climate change in this situation.
Observations reveal that traditional wintering locations had sparse butterfly populations, indicating a possible migration to higher, cooler areas of the mountains. This shift makes estimating population sizes more challenging, as many relocated groups fall outside of monitored regions.
Although the immediate risk of extinction is not a concern, the sustainability of their migration is under threat. The migration, which is the longest known of any insect species, encounters numerous challenges such as habitat destruction, particularly the loss of milkweed which is crucial for laying eggs, and the use of pesticides and herbicides in their migratory path across North America and Mexico.
In response to the dire situation, Humberto Peña, the leader of Mexico’s protected areas, has suggested the formation of a “safe corridor” through the United States and Canada. This corridor would aim to address the threats by reducing the use of pesticides and herbicides, implementing stricter deforestation controls, and protecting the milkweed habitats essential for the monarchs.
The continued existence of the monarch butterfly migration is in jeopardy, necessitating immediate and concerted efforts for its preservation. This extraordinary natural event depends on global cooperation and commitment to ensure its survival.
The populations of monarch butterflies in their winter habitats in Mexico have witnessed a dramatic decrease this year, showing a 59% reduction from prior counts. This significant drop to the second-lowest figure since records began is attributed to factors such as elevated temperatures, prolonged dry spells, and loss of natural habitats.
Monarch butterflies undertake a remarkable annual migration across North America, traveling from Canada and the United States to their wintering grounds in Mexico, a journey that no single butterfly completes in its entirety.
