Assessing Human Influence and Vegetative Dune Dynamics on Barrier Islands via Satellite Raster Classification

Barrier islands support ecological diversity and offshore ecosystems and provide critical protection to coastal communities. Climate change has intensified the frequency and severity of hurricanes affecting these islands, leading to ongoing erosion. The primary goal of this study was to explore the relationship between human intervention such as development and construction and the vegetative dune systems on Gulf Coast barrier islands in Alabama and Mississippi, USA. This research employed two decades of satellite images of three neighboring barrier islands and employed GIS raster classification to track changes in the vegetative dune system in terms of: (1) dune coverage (surface area of the vegetation), (2) vegetative maturity (vegetation type), and (3) stability (fluctuations in the vegetative coverage over time). Time series and trend analyses were used to compare the results for three neighboring islands. The findings show that Dauphin Island, which features both commercial facilities and vacation homes, exhibited a decrease in total area over time, and had the lowest percentage of vegetative dune coverage and highest level of vegetative fluctuation. In contrast, Petit Bois and Horn Islands, which remain untouched by human activity, displayed significantly higher levels of vegetative maturity and coverage and comparatively less fluctuation. This research provides a foundation for those advocating for dune restoration strategies, development limitations, and conservation regulations as nature-based infrastructure solutions to combat erosion on barrier islands and serves as a point of entry for future inquiries in the field of environmental management.