Targeting conservation activities: Cost-effective wetlands restoration in the Central Valley of California.

摘要

This dissertation is about the public benefits that wetlands can provide and how those benefits depend on where wetlands are located in the landscape. The two broad objectives of the research were (1) to further our understanding of the role that landscape configuration plays in the provision of ecosystem services from wetlands, and (2) to enhance our practical ability to account for spatial effects and tradeoffs between competing environmental goals when evaluating, designing, and implementing wetlands policies. Ecologists have generally ignored, or treated in a highly simplified manner, the economic constraints associated with conservation activities, and economists have only recently begun to address these issues. Most work to date on systematic conservation planning has focused on finding the best locations to set aside land for the protection of biodiversity. An economic approach to the problem, where biodiversity reserve networks are designed to maximize the number of species protected subject to budget constraint, has been shown to be much more cost-effective than the standard approach, where reserve networks are designed subject to an area constraint, ignoring differences in costs across sites. This research uses a budget-constrained approach to site selection, and is among the first to use spatially explicit models of production functions for ecosystem services in an optimization framework for prioritizing sites for wetlands restoration. Tradeoffs between two classes of ecosystem services from wetlands, habitat and water quality, were assessed in the Central Valley of California. Habitat benefits were estimated by a count regression model that relates breeding mallard abundances to the configuration of land use in the study area, and water quality benefits were estimated by a spatially distributed hydrologic simulation model of nonpoint source runoff and nutrient attenuation in wetlands. The results suggest that there could be large gains in effectiveness possible from a spatially targeted approach to selecting sites for wetlands restoration in the study area, and that there could be substantial tradeoffs between environmental benefits to consider.