Low average shoreline change rate in 51 years on the raised Aldabra Atoll

Aldabra Atoll, a raised atoll and UNESCO World Heritage Site in the Indian Ocean, has demonstrated remarkable resilience to sea level rise over 51 years. Despite regional sea level increases of 2–3 mm per year, 61% of its shoreline remained unchanged, while only 24% experienced low average change rates of 0.25 ± 0.36 meters per year—significantly lower than global atoll averages. Accretion and erosion were nearly balanced, affecting similar percentages (12%) of the shoreline, though localized changes included notable transformations like a sandy beach converting to mangrove habitat over 214 meters. Erosion impacted critical turtle nesting sites and the research station, while the lagoon shoreline showed more rapid changes than the ocean shoreline, particularly in areas exposed to wind and waves. The study, using aerial and satellite imagery analyzed via Digital Shoreline Analysis System, suggests that Aldabra’s adaptive capacity is comparable to other Indo-Pacific atolls, emphasizing the need for ongoing monitoring to inform conservation strategies and minimize local impacts on sediment dynamics.

Constance, A., Bunbury, N., Lack, N., Nebiker, S., Obura, D., Fleischer-Dogley, F., & Schaepman-Strub, G. (2024). Low average shoreline change rate in 51 years on the raised Aldabra Atoll. Scientific Reports, 14(1). https://doi.org/10.1038/s41598-024-74595-y