Implications of Cumulative Impacts to Estuarine and Marine Habitat Quality for Fish and Invertebrate Resources

Nearshore environments are nurseries for estuarine nekton and are preferentially sought out within an estuary. Habitat is the template on which population and community dynamics occur, and many linkages between habitat and nekton production are being altered by development. Thus, we are studying this linkage (function) while it is changing. We reviewed the literature on habitat alteration in nearshore environments, focusing on small-scale changes and their cumulative impacts. On a small scale, bulkheads and levees eliminate or significantly reduce access to intertidal marsh habitat, but these can accumulate to a larger area of impact, fragmenting habitat and reducing connectivity. Cumulative impacts are problematic because they are not immediately noted and build up over time to produce a more substantial impact. The creation of habitat patchiness (non-continuous segments) caused by development has received little attention but contributes to reduced environmental sustainability. Direct or indirect modification of landscapes influence access to nursery habitat for nekton and can reduce growth, increase mortality, and modify settlement and post-settlement habitat use patterns. Policymakers must make cumulative impacts an important item in their coastal management strategy, as there is growing evidence that created wetlands do not function like natural ones even after several decades.