The Sundarbans is the world’s largest mangrove forest, spanning across India and Bangladesh. Several studies have been conducted on various aspects of the ecosystem, primarily at a local scale, with most broad-scale studies confined to either the Indian or Bangladeshi part. To enhance the conservation and management of this extensive mangrove ecosystem, comprehensive studies encompassing the entire Sundarbans are essential. The available zonation maps are coarse and inconsistent across the two countries. Considering this, we aimed for a hierarchical zonation of all the Sundarbans. We performed geospatial analysis of high-resolution remote sensing images together with existing zonation information and geospatial characteristics. Using near-infrared and red bands, we derived NDVI and applied reclassification to obtain terrestrial areas of the Sundarbans.

We propose five hierarchical levels with over 200 geographic units at the lowest hierarchical level. Additionally, the data set is inclusive and existing zones/geographic units used in past studies are included. Geospatial analysis was employed to delineate territorial boundaries for each zone, incorporating canals, rivers, and adjacent oceanic areas. This approach accounts for the dynamic nature of mangrove islands, particularly those situated along the southern margin of the ecosystem. This was done to consider the dynamic nature of mangrove islands, especially the ones on the southern side of the ecosystem.

Such a geospatial data set enables a temporal comparison of geographic units for parameters such as vegetation and land area changes, especially after major cyclones. This study also demonstrates the use of this dataset in identifying vulnerable areas of the ecosystem using geospatial information on elevation, biomass, anthropogenic stress, and vegetation changes.