A MODEL FOR ESTIMATING SPATIAL SUBSIDIES ASSOCIATED WITH THE ECOSYSTEM SERVICES PROVIDED BY MIGRATORY SPECIES

Migratory species support ecosystem process and function in multiple areas, establishing ecological linkages between their different habitats. As they travel, migratory species also provide an array of services to people in many different locations, producing socio-economic linkages between different regions. These linkages create the potential for discrepancies between the areas that most support a species’ population viability – and hence their long-term ability to provide services – and those areas that benefit most as a result of services provided by the species. Even when such discrepancies are recognized, however, there is no established method for their quantification, or for the equitable redistribution of income that could help offset the cost of conservation efforts aimed at preserving a migratory species, its unique ecological functions, and the value we derive from them.

Utilizing examples of important migratory species, we present a conceptual framework for estimating both how much a particular location supports the provision of ecosystem services in other locations, and the extent to which locally derived benefits are dependent upon other locations. We further describe a method for estimating the net payment, or subsidy, owed by or to a location that balances benefits received and support provided by locations throughout the migratory range of multiple species. The ability to recognize and quantify these spatial subsidies from migration could provide a foundation for the establishment of markets that internalize the costs and benefits of protecting migratory species, thereby creating economic incentives for cross-jurisdictional cooperative management. The information requirements to fully realize the potential of this approach are substantial; new data, data-integration, and assessment methods are necessary. We argue, however, that the utility of ecosystem services as a framework for environmental management and conservation is severely limited without the capacity to explicitly account for migration and ecosystem services provided by migratory species.