Mapping the premigration distribution of eastern Monarch butterflies using community science data

Area of Science:

• Ecology
• Conservation Biology
• Entomology

Background:

• Effective conservation of migratory species requires knowledge of their distribution throughout their life cycle.
• Monarch butterfly (Danaus plexippus) overwintering sites are known, but premigration distribution data is limited.
• Previous studies relied on postmigration data, assuming equal mortality rates across natal origins, which may not be accurate.

Purpose of the Study:

• To estimate the premigration distribution of Monarch butterflies (Danaus plexippus) in North America.
• To identify key geographic areas and management jurisdictions crucial for conserving the premigration Monarch population.
• To provide a foundation for future research on migration mortality rates, distribution, and causes.

Main Methods:

• Utilized community science data collected before the fall migration period.
• Controlled for potential sampling biases in the citizen-reported data.
• Developed a distribution map to visualize Monarch abundance prior to migration mortality.

Main Results:

• Identified Minnesota, Texas, and Ontario as provinces/states with the highest estimated Monarch abundance before migration.
• Highlighted the importance of these regions for Monarch conservation, irrespective of their large geographical size.
• The generated map serves as a critical resource for understanding premigration population dynamics.

Conclusions:

• The premigration distribution map is essential for targeted conservation strategies for Monarch butterflies (Danaus plexippus).
• This research identifies key regions and management jurisdictions with significant responsibility for premigration Monarch conservation.
• The findings will aid future studies investigating Monarch migration ecology and mortality factors.