Loktak Lake, the largest freshwater lake in India, also called the only Floating lake in the world due to the floating phumdis (heterogeneous mass of vegetation, soil, and organic matters at various stages of decomposition) on it, is located near Moirang in Manipur state, India.The etymology of Loktak is Lok = “stream” and tak = “the end”.The Keibul Lamjao National Park, which is the last natural refuge of the endangered sangai or Manipur brow-antlered deer (Rucervus eldi eldi), one of three subspecies of Eld’s Deer, covering an area of 40 km2 (15 sq mi), is situated in the southeastern shores of this lake and is the largest of all the phumdis in the lake.
Phumdis are a series of floating islands, exclusive to the Loktak Lake in Manipur state, in northeastern India. They cover a substantial part of the lake area and are heterogeneous masses of vegetation, soil and organic matter, in different stages of decay. The largest single mass of phumdi is in the southeastern part of the lake, covering an area of 40 km2 (15.4 sq mi). This mass constitutes the world’s largest floating park, named Keibul Lamjao National Park. The park was formed to preserve the endangered Eld’s Deer subspecies, called Sangai in the Manipuri language, indigenous to this area.
Phumdis are used by the local people for constructing their huts for fishing and other livelihood uses, and are inhabited by about 4000 people. Athapums are artificial circular phumdis, built by the villagers as enclosures for fish farming; aquaculture has caused proliferation of the phumdis in the lake.
This ancient lake plays an important role in the economy of Manipur. It serves as a source of water for hydropower generation, irrigation and drinking water supply. The lake is also a source of livelihood for the rural fisherman who live in the surrounding areas and on phumdis, also known as “phumshongs”. Human activity has led to severe pressure on the lake ecosystem. 55 rural and urban hamlets around the lake have a population of about 100,000 people.
A rich biodiversity with habitat heterogeneity has been recorded during a scientific survey carried out between January 2000 and December 2002 in different habitat patches of the lake. The lake’s rich biological diversity comprises 233 species of aquatic macrophytes of emergent, submergent, free-floating and rooted floating leaf types.
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