Why in news?
Researchers from Nagaland University warned that changes in land use around rivers feeding Loktak Lake are deteriorating water quality. The study found that intensive agriculture, shifting cultivation and expanding settlements in the catchment have increased nutrient and sediment loads, threatening the lake's biodiversity and the livelihoods of local communities.
Background
Loktak Lake, situated in Manipur, is the largest freshwater lake in northeastern India. It is famous for its floating islands known as phumdis-mats of vegetation, soil and organic matter that provide habitat for numerous species. The lake supports irrigation, drinking water supply and fisheries for thousands of people. The Keibul Lamjao National Park, located on a phumdi, is the world's only floating national park and home to the endangered brow-antlered deer (Sangai). Loktak is listed on the Montreux Record of the Ramsar Convention due to ecological threats.
Key points
- Impact of land-use change: The nine rivers feeding Loktak Lake traverse agricultural fields, settlements and shifting cultivation areas. The study recorded elevated levels of nutrients, suspended solids and coliform bacteria in these rivers, indicating that runoff from farms and towns is degrading water quality. Excess nutrients accelerate the growth of aquatic weeds that choke waterways and disturb fish habitats.
- Ecological significance: Loktak hosts over 132 plant species and 428 animal species, including rare orchids, freshwater snails and the Sangai deer. The phumdis support around 200 aquatic plants and 400 animal species. These floating islands are vital nesting sites for birds and breeding grounds for fish.
- Threats to phumdis: The Ithai barrage built downstream maintains high water levels year-round, preventing phumdis from periodically touching the lakebed to replenish nutrients. As a result, the mats are thinning and breaking apart. Uncontrolled weed growth, pollution and land reclamation further threaten these unique ecosystems.
- Need for community-based management: The study recommends regulating land use in the catchment, controlling sediment runoff and involving local communities in conservation. Sustainable agriculture and eco-tourism could support livelihoods while reducing environmental stress on the lake.
Conclusion
Loktak Lake is a lifeline for thousands of people and a sanctuary for rare species. Protecting its water quality and floating islands will require integrated watershed management, strict pollution control and cooperation between government agencies and local communities.
Sources: The New Indian Express; NASA Earth Observatory.