Mapping the Migration

Abstract

Monarch butterfly populations have been declining at an accelerating rate. While local mitigative measures can provide some relief, the larger scale loss of habitat and lack of flyway continuity must also be addressed. This study utilized a site suitability model to rank all locations within the Western monarch migratory zone in relation to factors that collectively attribute to butterfly viability, sustainability, and functionality. The two overarching study goals were to identify flyway gaps and to compare the model outcomes with geolocated butterfly sightings. The model weighed temperature, precipitation, elevation, and land cover/use factors based on their overall impact on site suitability. In addition to these factors, wildfires, solar farms, genetically modified crops, snow/ice cover, and open water were modeled as uninhabitable zones incapable of sustaining butterfly populations. The study results illuminated the heterogeneity of the Western monarch migratory range as well as raised questions regarding possible abnormal butterfly behaviors.