Unmasking shoreline responses and land-use intensity on oceanic islands through a 26-year analysis from Gran Canaria

Human presence and activity on beaches have led to significant environmental and landscape transformations. This study provides an island-scale case study demonstrating how beach color and sediment composition have influenced urban and tourism development while affecting shoreline stability. This research also examines medium-term shoreline change of eighteen selected beaches on Gran Canaria (Canary Islands, Spain), across a gradient of human influence, as a representative case for oceanic islands undergoing intense development pressure. Geographic information systems (GIS), historical and current orthophotos (1998–2024), and official inventories provided multi-source data to classify beach types according to their use and transformation degree, analyze the beach shoreline evolution with the Digital Shoreline Analysis System (DSAS), and finally unmask the true beach shoreline trend after identifying the interventions produced on them. Results reveal heterogeneity with three shoreline evolution trends: i) natural beaches exhibiting stable or progradational shorelines; ii) urban beaches displaying higher alteration rates and greater dependency on engineered sediment management; and iii) semi-urban beaches showing intermediate dynamics, influenced by both natural and anthropogenic processes. Critically, this evidence establishes an empirical foundation for developing differentiated coastal management strategies for beaches. These strategies should emphasize adaptive approaches that balance conservation objectives, climate change response, and coexistence with tourism and urban pressures.