A BSIP study (June 2026) reconstructed nearly 4,000 years of climate, vegetation and flood history on Majuli Island by analysing pollen and sediment cores, providing palaeo‑climatic baselines for adaptation in the Brahmaputra floodplain.
Geographical & Ecological Profile
- Formation & Boundaries: Fluvial river island of the Brahmaputra alluvial valley; bounded by the Brahmaputra (south), Kherkutia Xuti (north) and Subansiri (NW).
- Wetlands (Beels): Network of beels acting as habitats for migratory birds and indigenous fish; hydrological buffers within the floodplain.
- Important Bird Area: Wetlands designated IBA; hosts threatened species such as the Greater Adjutant Stork.
Key Findings of the BSIP Study
- Method: Palynology and sedimentology used to reconstruct 4,000 years of environmental change.
- Early Holocene Phase (~4,000 BP): Warm, humid interval with intensified monsoon and high sediment deposition.
- Monsoon Variability: Alternating wet and dry centuries drove shifts in river course, discharge and flood frequency.
- Little Ice Age Signal: Cooling/drying phase correlating with the global Little Ice Age (approx. 14th–19th centuries).
Challenges
- Riverbank Erosion & Area Loss: Island area declined from ≈1,200 km² (early 20th c.) to <500 km² (early 21st c.) due to bank slumping and avulsions.
- Drivers: High monsoon discharge, loose alluvial soils, increased sediment load from upstream deforestation (Arunachal Pradesh, Tibetan catchments) and episodic flash floods.
Adaptation Strategies
- Eco‑engineering: Deep‑rooted grasses (vetiver, Bermuda) and geo‑textile sand bags for bank stabilisation.
- Wetland Restoration: Rejuvenation of beels to act as floodwater sponges and recharge groundwater.
- Community Measures: Flood‑resilient practices — Bao dhan (deep‑water rice), and elevated Chang ghar stilt houses.
IASPOINT Booster Facts
- First river‑island district: Declared in 2016 by the Government of Assam.
- Guinness record: World’s largest inhabited river island (surpassed Marajó).
- Palynology: Study of pollen and spores from sediments to reconstruct past vegetation and climate.