Estuarine habitat equivalency ratios based on production at multiple trophic levels for use in compensatory restoration

Restoration of estuarine habitats often involves conversion of less valued habitats into those with biogenic structure.  These structured habitats are assumed to provide highest ecosystem services.  The benefits of such compensatory restoration can be quantified using habitat equivalency ratios, which compare relative productivity of different habitat types.  Recently, ratios have used secondary production, since it is easily measured and may account for biogenic structure.  Despite the importance of such ratios, no synthesis of data comparing secondary production in alternative estuarine habitats is available.  We conducted a synthesis of available production data from the east coast of the United States.  Also, we conducted corresponding field experiments to quantify secondary production.  Data were collected from fringing salt marsh, intertidal flat, seagrass, subtidal flat and oyster reef habitat.  Our data synthesis showed that oyster reefs are an order of magnitude higher in secondary production than in other habitats.  Most surprisingly, secondary production was similar between all other habitat types, regardless of presence or absence of structure.  To explain these results, we also synthesized data for primary and tertiary production.  All habitats had ratios of productivity across trophic levels that did not conform to standard trophic transfer efficiencies.  This suggests that changes in one trophic level are not always reflected in others within a single habitat type.  Based on our results, we suggest ways in which habitat equivalency ratios used in compensatory restoration be better calculated.  We compare the east coast production data to data collected from field experiments.