Monarchs Die by the Millions in Mexican Storms

MEXICO CITY, Mexico, February 14, 2002 (ENS) - A severe winter storm that swept across the Mexican state of Michoacán in January has killed as many as 250 million Monarch butterflies on their wintering grounds, according to the World Wildlife Fund Mexico.

Monarch butterfly biologist Dr. Lincoln Brower estimates that 80 percent of the El Rosario Monarch colony and 74 percent of the Chincua colony could have died as a result of these severe climate conditions.


Dr. Lincoln Brower, shown here at Sweet Brier College. (Photo courtesy Sweet Briar)
Dr. Brower, professor of zoology at the University of Florida, considers this to be the worst mortality he has witnessed in his 25 years of studying and visiting the Monarch colonies in Mexico.

Still, Monarch butterfly population experts say, the total number of dead Monarchs is greater than previous estimates for total living Monarchs in these colonies. Scientists are now reevaluating the butterfly populations.

The director of the World Wildlife Fund (WWF) Mexico Program Office, Juan Bezaury Creel, said that the high mortality "has coincided with a year when an exceptionally high number of Monarchs arrived to the overwintering sites."

The unique high altitude pine-oyamel fir forest ecosystem of the states of Mexico and Michoacan, provides critical winter habitat for millions of Monarch butterflies that migrate 2,500 miles from Canada and the United States.


Monarch butterflies in Mexican pine-oyamel fir forest (Photo courtesy Mexico Connect)
For the past two decades, these forests have been logged and severely fragmented, and the deforestation may have contributed to the massive Monarch deaths, conservationists say. They have been warning for years that the Monarch population would suffer if logging continued to degrade their forest habitat.

The freezing temperatures on January 12 and 13 were severe but not record breaking. World Wildlife Fund Mexico says the mortality "may be attributed to the deadly combination of severe wet rains followed by freezing temperatures since it has been demonstrated that dry Monarchs can survive at lower temperatures" than wet ones.

A healthy and intact forest serves both as an umbrella and a blanket that protects the monarch colonies from severe weather.

The government of Mexico expanded the Monarch Butterfly Biosphere Reserve in November 2000, and WWF Mexico reports that since then the total volum of wood taken from the core zone of the reserve where most of the butterflies overwinter has been cut to "minimal levels." Local community leaders and an increased law enforcement presence have helped halt the logging.

At the end of November 2001, President Vicente Fox announced the creation of the Monarch Butterfly Conservation Trust Fund, a six million dollar trust fund which will provide the necessary financial resources to support longterm conservation activities by the local communities within the core zone. In collaboration with the Fondo Mexicano para la Conservación de la Naturaleza (FMCN), WWF helped the Mexican government design this conservation strategy to protect the butterflies.

It is the first time in Mexico’s history that a conservation trust fund has been created specifically to offer incentives to local communities who will receive payments to perform conservation and sustainable use activities instead of logging.