Monarch butterfly overwintering sites in Mexico are critical to population survival. Protecting these sites from logging and disturbance delivers direct welfare benefits to billions of overwintering individuals.
The concentration of potentially billions of monarch butterflies in small overwintering forest patches creates both opportunity and vulnerability for welfare at enormous scale. When overwintering conditions are appropriate, monarchs experience a dormant state that minimizes energy expenditure and enables survival through winter. Logging that reduces forest cover or opens gaps exposes butterflies to lethal cold or warm temperature extremes that kill concentrated populations. A single severe weather event or logging incursion can kill tens of millions of individuals simultaneously. Protecting the specific microclimate characteristics of overwintering forests through zero-tolerance logging enforcement and community economic incentives prevents welfare catastrophes at a scale almost impossible to achieve for any other species conservation intervention.