Valuing beach ecosystems in an age of retreat

摘要

California's coast is eroding, along with its iconic sandy beaches. As a result, the pressure for already extensive coastal armoring of these dynamic shorelines is increasing. Beach loss will accelerate with sea level rise, as will the rate of armoring, unless checked by major public policy initiatives. To conserve functional beach ecosystems for the public good, adaptation strategies need to include preservation of shorelines without armoring and the restoration of natural coastal processes. As in many other ecosystems, investigations of the full value of ecosystem services of intact dune-beach-surf zone systems and the development of protocols for robust measurement of indicators of those services are incomplete. Consequently, valuation of the ecological functions and services (except for storm buffering and recreation) of beaches are rarely applied to mitigate for armoring projects. To move forward in developing a viable approach for mitigating the increasing losses to sandy beach ecosystems associated with the multitude of coastal armoring projects on open coast sandy shorelines, we considered several economic valuation methods and suggest that ecosystem replacement cost should be considered as part of any mitigation strategy. Using this framework, we propose a mitigation system for shoreline armoring projects that is: 1) intended to minimize long term loss of the resources and services of intact beach ecosystems, 2) based on simple metrics, 3) easy to interpret and apply, and 4) capable of being used in conjunction with a mitigation banking system.