Assessment of Wetland Change, Community Participation, and Nature-Based Conservation Options of Tanguar Haor, Bangladesh

Abstract

Tanguar Haor, a Ramsar Wetland of International Importance in Sunamganj District, Sylhet Division, north-eastern Bangladesh, is among the most ecologically significant freshwater wetlands in South Asia, supporting over 140 fish species, 51 or more migratory bird species, and the livelihoods of roughly 30,000 people in about 40 surrounding villages. Despite its Ramsar status, the wetland has faced sustained anthropogenic and climatic pressure. This study presents a five-period (1990, 2000, 2010, 2020, 2024) multi-temporal assessment of wetland change using Landsat 5 TM, 7 ETM+, 8 OLI, and 9 OLI imagery processed on the Google Earth Engine (GEE) cloud platform, supplemented by SRTM 30 m elevation data. Open-water extent was mapped using the Normalized Difference Water Index (NDWI), vegetation condition with the Normalized Difference Vegetation Index (NDVI), and land cover with Maximum Likelihood Classification (MLC). The results show an 84.2% decline in mapped open-water area, from 85.83 km² in 1990 to 13.54 km² in 2024, consistent with published evidence of wetland transformation across Bangladesh. Vegetation and terrain analyses confirm a low-relief basin highly sensitive to hydrological disturbance. The paper further examines community participation in wetland governance and proposes five nature-based conservation options — hydrological restoration, community fish sanctuaries, native vegetation rehabilitation, seasonal agricultural zoning, and community-linked ecotourism — arguing that GIS-based monitoring must be integrated with participatory, gender-inclusive governance for long-term conservation success.