Participation in the convention on migratory species: A biogeographic assessment

The Convention on the Conservation of Migratory Species of Wild Animals (CMS) is a Multilateral Environmental Agreement (MEA) focused on species that regularly travel across international borders. Despite covering an important group of species, CMS is under-utilized compared to other conservation-focused MEAs. CMS suffers from a lack of participation across North America and most of Asia. Our goal is to illustrate differences in species richness and average range-size across signatory and nonsignatory nation-states using range-diversity plots. We also show differences in the cost of CMS membership relative to species patterns to highlight which countries may be discouraged from becoming CMS signatories. Despite containing many CMS species, large economies such as the United States, Russia, and China are not members of the convention. To facilitate migratory species conservation into the future, CMS should seek to fill gaps in participation, potentially directing recruitment efforts toward nonsignatory states that would receive the largest benefit at the lowest relative cost.