Using community science to map western monarch butterflies (Danaus plexippus) in spring

Area of Science:

• Ecology and Conservation Biology
• Entomology
• Citizen Science Applications

Background:

• Migratory species conservation requires understanding their full annual cycle, including periods of low abundance.
• Western monarch butterflies (Danaus plexippus) have faced significant population declines.
• Early spring is a critical but poorly documented period for western monarch breeding and population expansion.

Purpose of the Study:

• To investigate the distribution and potential breeding habitat of western monarch butterflies during the understudied early spring period.
• To assess the effectiveness of community science initiatives in gathering data on rare migratory species.
• To understand the factors contributing to population expansion from overwintering sites.

Main Methods:

• Utilized data from a community science initiative, the Western Monarch Mystery Challenge, from February 14th to April 22nd over three years.
• Integrated data from iNaturalist to supplement monarch distribution records.
• Analyzed monarch records to identify potential early spring breeding habitats across multiple ecoregions.

Main Results:

• Identified potential early spring breeding habitats for western monarchs spanning a large geographic area and diverse ecoregions.
• Observed monarchs likely eclosed in the current year, indicating both movement and reproduction contribute to early spring population growth.
• The Western Monarch Mystery Challenge yielded significantly more early spring records (33.0/year) compared to previous years (5.1/year).

Conclusions:

• Community science initiatives are valuable tools for increasing data collection on rare species during critical life cycle stages.
• Early spring monarch observations suggest a combination of dispersal and reproduction drives population expansion.
• Further research and sustained community science efforts are crucial for effective western monarch conservation.