Distribution of exotic mangroves Sonneratia apetala in China for 2024

In China, previous studies focused on the total area of mangroves using remote sensing technique, neglecting expansion of the exotic mangrove species Sonneratia apetala, even when the species is encroaching on habitat of native species. We proposed a robust and interpretable approach to identify the exotic species, applied this approach to generate S. apetala map in China for 2024 using Sentinel-1/2 imagery, and revealed its expansion since start of the SDGs by combining existing datasets.

The approach, in the form of a decision rule — VH ≥ –14.390 & B11 < 0.084—achieved an overall accuracy of 97.0% for the generated S. apetala map. Evaluated using 159 field samples, the S. apetala map for 2024 achieved an accuracy of 91.8%. The total area of the exotic species in China for 2024 was 3675 ha, which is ~ 1.25 times the area in 2020 and ~ 1.99 times the area in 2016.