Assessing Coastal Dune Vegetation Trajectories and Eco-Geomorphological Resilience Under Thermal and Hydric Stress Signals Across Five Beaches of Santa Marta, Colombia from 2015 to 2025

The coastal dunes of the Colombian Caribbean show highly variable vegetation dynamics between 2015 and 2025. The study was conducted on five different beaches: Lipe, Salguero, Costa Verde, Gairaca, and Mendihuaca. Satellite images and SAVI estimates were used to evaluate changes in vegetation cover. The results show that Gairaca and Mendihuaca are ecosystems with the greatest ecological stability, due to their high vegetation values, lower mobile-sand presence, better moisture retention, and lower thermal stress. On the other hand, Lipe, Salguero, and Costa Verde show more fragmented cover, dominated by sparse vegetation and bare soils, which demonstrate greater geomorphological and ecological vulnerability. The period from 2015 to 2020 shows a general decrease in vegetation vigor, possibly related to water stress and adverse climatic conditions. After 2020, there were signs of recovery, although not with the same intensity at all sites. Salguero showed vegetation recolonization but still did not present structural consolidation. Lipe was the most unstable system, with greater degradation and low recovery capacity. This study confirms that vegetation cover is a key indicator of resilience, stability, and ecological succession in coastal dunes.