Wetland mapping at 10 m resolution reveals fragmentation in southern Nigeria

Abstract Wetland ecosystems play key roles in global biogeochemical cycling, but their spatial extent and connectivity is often not well known. Here, we detect the coverage type of wetlands at 10 m resolution across southern Nigeria (total area: 147,094 km 2 ), thought to be one most wetland-rich areas Africa. We use Sentinel-1 Sentinel-2 imagery supported by 1500 control points for algorithm training validation. estimate that swamps, marshes, mangroves, shallow water cover 29,924 with 2% uncertainty 460 . found larger mangrove smaller marsh than suggested earlier, coarser studies. Average continuous wetland patch were 120, 11, 55 13 mangrove, marsh, swamp, respectively. Our final map pixels captures small patches which may have been observed earlier mapping exercises, 20% being < 1 ; these clustered around urban centres, suggesting anthropogenic fragmentation. approach fills a knowledge gap between very local (< 400 ) studies reliant on field aerial photos, low (> 250 pixel dimensions) datasets provides data critical both improving land-surface climate models conservation.