Using remote sensing to evaluate coastal erosion and accretion to guide conservation of turtle nesting sites

Using a remote sensing approach, we examined changing patterns in currents, waves, and tides and their impacts on coastal erosion and accretion at Jeen Womom Turtle Nesting Coastal Park (JWTNCP) in West Papua, Indonesia. This area is part of one of the most diverse marine ecosystems in the world and is used by four species of sea turtles. We quantified rates of coastline changes and oceanographic dynamics between 2012 and 2018 using remote sensing interpretation methods with data compiled from Landsat 8 and two oceanographic data providers: Indonesia Geospatial Information Agency and Copernicus Marine Environment Monitoring Service. We found evidence that coastlines were both eroding and accreting with high variation among years. In general, we found that areas with evidence of accretion were those near river deltas where sedimentation from rivers counteracted erosion from waves. In all other areas, coastlines were dominated by erosion due to increased wave strength at high tides and related to sea-level rise. We suggest that turtle nesting conservation should prioritize efforts near river outlets where beaches are likely to persist for a longer duration than other areas.