Spatial ecological and economic subsidies of the monarch butterfly (Danaus plexippus) in eastern North America

ABSTRACT The monarch butterfly migration of eastern North America has declined substantially over the last two decades. As the three nations spanned by their migration embark upon a tri-national conservation effort aimed at reversing this decline, numerous quantitative ecological analyses have been conducted to inform conservation planning. In addition to this ecological information, it is also important to consider socioeconomic factors that can provide an indication of societal benefit from the monarch butterfly and willingness to engage in conservation activities throughout the migratory range. To this end, we quantified the spatial subsidies—a measure of the mismatch between where people receive economic benefits from a migratory species and where the migratory species receives ecological benefits from ecosystems—generated by the annual monarch migration across eastern North America. Spatial subsidies explicitly link human beneficiaries of ecosystem services derived from migratory species with the ecosystems upon which those benefits depend. Despite the ecological importance of the monarch’s breeding range, we found that social benefits provided by monarchs in the U.S. and Canada are being subsidized at a regional level by migration and overwintering habitat in Mexico. This subsidy results primarily from the much larger number of people living in the northern portion of the monarch range who benefit from the cultural ecosystem services provided by monarchs. At a sub-regional level, results from a hypothetical example suggest that rural landowners are subsidizing urban residents throughout the monarch range, linking rural conservation investment to urban benefits.

Spatial ecological and economic subsidies of the monarch butterfly (Danaus plexippus) in eastern North America