Vulnerability and conservation value of monarch butterfly ( <i>Danaus plexippus</i> L.) roosting habitats east of the Appalachian Mountains, USA

Abstract The monarch butterfly ( Danaus plexippus L.) is a flagship species and pollinator with declining populations. The largest monarch population overwinters in Mexico and completes a fall migration from spring and summer breeding grounds in North America. During fall migration, monarchs fly diurnally and roost nocturnally in aggregations. A roosting habitat is essential to the fall migration; however, stressors such as habitat loss owing to development and climate change endanger these habitats. We sought to determine the vulnerability to loss of a monarch roosting habitat in the Atlantic region. Additionally, we evaluated the connectivity of this habitat with lands currently in conservation management. We conducted a vulnerability assessment of a predicted roost habitat, evaluated habitat connectivity with Morphological Spatial Pattern Analysis, used Zonation to create a relative ranking of areas in the Atlantic region for monarch roost site conservation and mapped Zonation‐ranked areas per their current predicted vulnerability. Predicted suitable roost habitats that occurred in coastal areas were more vulnerable (average vulnerability 54.6 [possible range 0–100]) than those farther inland (average vulnerability 44.6). Most (73%) roosting habitats occurred within large patches, many of which are within the average daily flight distance of monarchs. There was little overlap (7%) between areas with high predicted roost habitat value and current conservation lands. Current conservation actions may be insufficient to preserve the monarch fall migration in the Atlantic region. Continuation of the migration may benefit from management actions within lands managed for conservation and nectaring habitats found outside of protected lands.