The influence of inland habitat conditions on the status of estuary

Observations worldwide of eutrophication, hypoxia, and contaminant loadings in estuaries have prompted researchers to wonder how the condition of coastal and estuarine habitats is influenced by local compared to upriver conditions and how human disturbances are modulated on different spatial scales. Recent progress in characterizing the condition of both riverine and coastal habitats through the National Fish Habitat Action Plan (NFHAP) has allowed us to directly address these challenging questions. NFHAP's inland assessment initially characterizes 17 types of riverine habitat impacts using multivariate approaches that weight impacts based on biological response. To examine how these impacts affect estuarine condition and how they are modulated by watershed size, region and latitude, we analyzed dependency of inland and estuarine variables and compared “disturbance scores” for areas within 1) the same hydrologic unit as the estuary, or 2) units upstream of the estuary's hydrologic unit. We used general linear models to relate these two sets of data to a number of variables focusing on water quality and eutrophication metrics as publicly reported by multiple agency efforts throughout the U.S. This novel approach provides insight into the links between inland water quality and the condition of coastal habitats.