Each fall, the monarch butterfly, instantly recognized and beloved by children and adults throughout North America, travels thousands of miles to 12 mountaintops in central México to spend the winter from November to March. This is one of the most spectacular migrations carried out by an insect. And yet, the monarch’s migration is in peril. Habitat loss at the monarch’s winter home in Mexico threatens the survival of this amazing migration.
The overwintering environment in Mexico is a ruggedly mountainous terrain, remote, and densely forested by stately pine trees and oyamel firs. Monarchs cluster in pendulous masses, occasionally flying to drink from nearby streams. The oyamel thrives at the high altitudes (over 10,000 feet), with a number of pine species growing further down the slopes. Below the mountain tops, the once-forested lands have been cleared over the decades for subsistence agriculture, and for wood and timber for domestic use by the region’s poor residents. These vital forests are also the upper peaks of the watershed that provides drinking water for Mexico City and serve as an important carbon sink and oxygen generator.
The Reserve, designated by the United Nations as a World Heritage Site, was created to protect the monarch colonies’ largest and most frequently established overwintering sites. No logging is permitted within the core zone of the Reserve, and only managed cutting is allowed in the buffer zone. However, illegal logging for commercial gain occurs in both areas. Governmental patrols strive to reduce illegal logging, but this is difficult given the isolation, the terrain, the complex local governance, and the economic appeal of timber. Irresponsible tree removal in the core and buffer zones creates ‘holes in the blanket’ subjecting the monarchs to a freezing death during occasional fierce winter storms, such as the mass destruction that occurred in January 2002 that killed a quarter of a billion monarchs.