A Review of Habitat Impacts from Residential Docks and Recommended Best Management Practices with an Emphasis on the Northeastern United States

Small docks and floats are common in estuaries and coastal waters worldwide. These structures serve a role in coastal recreation by facilitating access to waterways. However, they can impact shoreline ecological function. While individual environmental impacts are generally minor, increasing dock proliferation and overlap with sensitive coastal resources can result in cumulative impacts that pose threats at the ecosystem level. Docks promote changes in habitat and aquatic communities through alteration of environmental conditions. Here, we review the potential environmental impacts of docks on estuarine and coastal flora and fauna and discuss best management practices (BMPs) to avoid or minimize such impacts with a focus on New England. We consider impacts in relation to the structural components of docks: the piles, decking, and floats. Impacts to salt marsh and submerged aquatic vegetation are a particular focus given the important ecosystem services these vegetated habitats provide and their vulnerability to dock-induced habitat alteration. Potential environmental impacts depend on structure size, design, and location, and can include both short-term (e.g., turbidity from pile installation) and long-term (e.g., salt marsh loss from chronic shading) effects. Such effects can be minimized through BMPs (e.g., construction outside sensitive time-of-year periods, designs to reduce shading). As BMPs tend to reduce rather than avoid environmental effects, cumulative impacts also need to be considered in the permitting process. We recommend that managers develop plans or bylaws that identify sensitive habitats where dock construction should be avoided as well as BMPs to make remaining dock proliferation less impactful.