ECOMORPHODYNAMIC FEEDBACKS AND COUPLINGS BETWEEN LANDSCAPE UNITS AFFECT BARRIER ISLAND RESPONSE TO CHANGING CLIMATE

摘要

Because barrier islands are low-lying and dynamic landforms they are sensitive to changing environmental conditions such as rising sea level, increases in the frequency of strong storms, and changes in the species composition of coastal vegetation. The continued existence of barriers will depend on the degree to which they can maintain elevation above sea level and migrate landward as conditions change. Interactions between ecological and morphodynamic processes (i.e., ecomorphodynamics) play a critical role in determining how barrier systems will evolve in the future. Model experiments and observations illustrate the importance of ecomorphodynamic feedbacks, as well as couplings between island and backbarrier marsh environments, in influencing 1) the rate of formation, maximum height and morphology of coastal dunes, 2) overall island state (high vs. low) and the potential for rapid transitions in state to occur in response to gradually changing forcing; and 3) the persistence of back-barrier marshes, and thus the influence of back-barrier marshes on the rate of migration of barrier islandmarsh systems.