Geo-ecological dynamics of Bhairabkunda Grasslands: flood origins, florican dependence, and conservation need
DOI:
https://doi.org/10.11609/jott.10326.18.9.29743-29750Keywords:
Bengal florican, emerging grassland, flood dynamics, habitat management, hydrological changes, land cover change, long-term monitoring, sub-Himalayan grassland, vegetation successionAbstract
This study investigated the dynamics of land cover change in the Bhairabkunda region of Assam, with a focus on the emergence of grasslands resulting from flood-driven river course changes. The objective was to assess how flooding events and subsequent ecological succession influenced grassland formation and their role in supporting the ‘Critically Endangered’ Bengal Florican Houbaropsis bengalensis. Multi-temporal satellite imagery from Landsat 5, 7, 8, and 9 (1987–2024) with 30 m spatial resolution was analyzed using supervised classification in QGIS to quantify land cover transitions. Ground surveys were conducted in 2024 to validate florican presence and vegetation composition. The results revealed that significant grassland patches emerged after the 1988–1989 floods, which altered the river’s course and deposited sandbars, leading to 9.64 km² of grassland by 1991. However, between 2015 and 2024, rapid woodland expansion reduced grassland to 6.29 km², threatening grassland-dependent species. Bengal Florican sightings during field surveys confirmed the ecological significance of these newly formed habitats. Future projections for 2034, based on the MOLUSCE artificial neural network model, indicated further grassland decline to 4.72 km² and woodland expansion to 9.87 km². These findings demonstrated the dynamic nature of floodplain ecosystems, the influence of hydrological changes on vegetation succession, and the vulnerability of specialized species to habitat contraction. The study concluded that continued monitoring and targeted habitat management are urgently required to conserve grassland ecosystems and ensure the survival of the Bengal Florican in the sub-Himalayan landscape.
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