The monarch butterfly in Mexico: a conservation model.

Area of Science:

• Ecology
• Conservation Biology
• Entomology

Background:

• Millions of monarch butterflies (Danaus plexippus L.) migrate annually from North America to overwintering sites in Mexico and California.
• The International Union for Conservation of Nature (IUCN) listed migratory monarchs as endangered in 2022 due to significant population declines.
• Key drivers of monarch decline include herbicide use, climate change impacts, and habitat loss from land-use changes.

Purpose of the Study:

• To analyze conservation actions for monarch butterfly overwintering sites and migration.
• To evaluate the effectiveness of the Monarch Butterfly Biosphere Reserve established in 2000.
• To emphasize the importance of monitoring overwintering monarch colonies in Mexico.

Main Methods:

• Analysis of conservation strategies implemented for monarch overwintering sites.
• Review of the establishment and impact of the Monarch Butterfly Biosphere Reserve.
• Monitoring of the area covered by overwintering monarch colonies in Mexico over the last decade.

Main Results:

• The Monarch Butterfly Biosphere Reserve was established in 2000 as a key conservation action.
• Conservation of overwintering sites in Mexico represents ongoing efforts since their discovery.
• Over the past 10 years, overwintering monarch colonies in Mexico covered an average area of 2.72 hectares (±0.47 SE).

Conclusions:

• The conservation of monarch overwintering sites in Mexico is a critical and continuous effort.
• Monitoring the area occupied by these colonies is essential for understanding population status.
• These large concentrations of monarch butterflies are vital for the species' survival.