Cumulative Habitat Impacts of Nearshore Engineering

A multi-disciplinary, multi-institutional research team evaluated a broad range of physical and biological characteristics at six Great Lakes nearshore sites in order to develop and test a conceptual modeling framework to assess linkages between bluff erosion, sediment supply, coastal processes, and biological utilization of nearshore and coastal habitats. The sites were chosen to represent a broad range of hydrogeomorphic conditions, with the objective of assessing the response of these nearshore systems to anthropogenic modifications and coastal change. As a result of this 2-year field effort, new methods and integrated approaches were developed to characterize, map, and assess the dynamic nature of the nearshore zone (area generally less than 10 m water depth). Thus, these data provide an initial quantitative assessment of nearshore change. In addition, our data indicate that shoreline modifications have led to cumulative impacts that have irreversibly modified Great Lakes nearshore coastal habitats and the processes that create and maintain them. Of special note is our observation that altered nearshore substrate dynamics resulting from shoreline modifications may enhance the colonization success of lithophilic aquatic invasive species in nearshore areas of the Great Lakes. Continued development of the shoreline may exacerbate changes in Great Lakes nearshore food-web structures and ecosystem services. Further study and monitoring of these phenomena are needed, and our work suggests that a holistic, multidisciplinary approach is necessary to develop effective management strategies to address these and other issues affecting nearshore areas of the Great Lakes.