Integrating biology and economics in seagrass restoration: How much is enough and why?

Although success criteria for seagrass restoration have been in place for s ome time, there has been little consistency regarding how much habitat shou ld be restored for every unit area lost (the replacement ratio). Extant suc cess criteria focus on persistence, al ca, and habitat quality (shoot densi ty). These metrics, while conservative, remain largely accepted For the sea grass ecosystem. Computation of the replacement ratio using economic tools has recently been integrated with seagrass restoration and is based on the intrinsic recovery rate of the injured seagrass beds themselves as compared with the efficacy of the restoration itself. In this application, field su rveys of injured seagrass beds in the Florida Keys National Marine Sanctuar y (FKNMS) were conducted over several years and provide the basis for compu ting the intrinsic recovery rate and thus, the replacement ratio. This comp utation is performed using the Habitat Equivalency Analysis (HEA) and deter mines the lost on-site services pertaining to the ecological function of an area as the result of an injury and sets this against the difference betwe en intrinsic recovery and recovery afforded by restoration. Joining empiric al field data with economic theory has produced a reasonable and typically conservative means of determining the level of restoration and this has bee n fully supported in Federal Court rulings. Having clearly defined project goals allows application of the success criteria in a predictable, consiste nt, reasonable, and fair manner. Published by Elsevier Science B.V.