Indices of biotic integrity in stated preference valuation of aquatic ecosystem services

Stated preference surveys often give minimal attention to distinctions between intermediate and final ecosystem services, leading to the potential for welfare estimates that overlook, misrepresent or double count associated values. This paper illustrates potential mechanisms through which multimetric indexes of the type developed in the ecological literature, here an index of biotic integrity, can be used within stated preference survey scenarios to both improve the validity of survey responses and provide otherwise unavailable information on willingness to pay for intermediate and final ecosystem services. We illustrate the approach using a choice experiment application to the restoration of migratory fish in a Rhode Island watershed. Where assumptions of the model hold, results can allow transparent disentanglement and estimation of marginal values for both intermediate and final ecosystem services.