MEXICO CITY – Mexico has seen fewer hectares (acres) occupied by the monarch butterfly during its latest hibernation in the forests of the nation’s central region, the head of the National Natural Protected Areas Commission, Luis Fueyo, said.

According to recent monitoring, during the 2011-2012 season a total of 10 hibernating colonies occupied 2.89 hectares (7.13 acres) of woodland in the states of Michoacan and Mexico, some 28 percent less than the 4.02 hectares (10 acres) the year before.

Fueyo told a press conference that the decline was caused by the drought in the fall of 2011, coinciding with the migration period of the monarch, which soars thousands of kilometers (miles) from the United States and Canada to the Mexican forests.

He recalled that during the last 19 seasons there have been wide fluctuations in the extension of colonies, from a high of 18.9 hectares (46.7 acres) in 1996 to a low of 1.92 hectares (4.7 acres) in 2009.

The official said the extent of woodland occupied by the colonies is used as an indicator of the population migrating to Mexico each year, instead of numerical estimates which are more prone to error.

Fueyo said that the conservation of the monarchs is a concern not only for Mexico but also for the United States and Canada where they reproduce and where, in his opinion, it is a vital necessity to control the use of insecticides and other chemicals that affect the butterfly’s survival.

For his part, the Mexican director of the World Wildlife Fund, Omar Vidal, said that, apart from the effects of climate change such as drought, the use of insecticides affects plants that nourish the larvae and increase the mortality rate of the monarch butterfly during migration. EFE