Manipur, Jul 29 (IANS/Mongabay): The states iconic Loktak Lake and its floating islands (phumdis), the last natural refuge of the critically endangered Sangai deer, are losing ground to mushrooming agricultural practices and human settlements, reports a study.

Changes in land use patterns may be linked to the construction of the Ithai barrage in 1979, downstream of Manipur river, for the Loktak Hydroelectric Project.

There is a need for regular monitoring and implementing proper land use practices in and around the lake in order to restore the degraded ecosystem plagued by pollution and an altered aquatic regime.

The 246.72 square km lake is a Ramsar Wetland of International Importance cradled in the floodplain of the Manipur river. About an hour and a half from Manipur's capital Imphal, the lake and the resident Sangais are the principal attractions for travellers.

A source of water for hydropower generation, irrigation and drinking water supply, the lake has become a hotbed of tourism and related developmental activities.

Using satellite data from 1977 to 2015 (from the pre-barrage to post-barrage period), scientists have mapped the decline of the phumdis that are critical in supporting the weight of these animals (also called dancing deer for their dainty gait) as they negotiate their way through the floating islands.

"We have observed a loss in phumdi area that is equivalent to more than double the increase in agricultural areas in a span of 38 years from 1977 to 2015," Rajiv Kangabam, from Assam Agricultural University and lead author of the study, told Mongabay-India.

Protecting the wetlands ecosystem with the phumdis is crucial to conserve the Sangais, because the beautiful animals are concentrated in the 40 square km Keibul Lamjao National Park (KLNP), that is a floating meadow. It is considered as the only floating reserve in the world.

Only 260 dancing deer remain, as per the forest department while biologists from Wildlife Institute of India say the figure is less than 100 adult breeding individuals. The Sangai was believed to have gone extinct until a remnant population was discovered in the early 1950s.

Ubiquitous in folk art and lore, the Sangai (Rucervus eldii eldii) is also the state animal of Manipur.

The phumdis are floating mats of soil, plants and organic matter at various stages of decomposition, all naturally bundled together. Part submerged, part floating they are the elements that impart uniqueness to the Loktak ecosystem. Two-thirds of the saucer-shaped lake is dotted by these floating meadows.

"It was estimated that 20,000 ha (83,000 ha unofficial) of arable land was submerged resulting in the loss of employment of the local people. This led to increase in human pressure on the lake resources leading to increase in human settlement and a high demand for fish," Kangabam said.

The authors of the study also identified the need for the proper implementation of the Manipur Loktak Lake (Protection) Act, 2006 in order to guide the increasing anthropogenic activities in the area, to protect the Loktak through sustainable management and conservation of the rich biodiversity.

"There is a need to balance ecological protection and human needs. Without provision of alternative livelihood options, the human pressure on the lake will go up and this will be disastrous for the lake," Kangabam said.

Oinam Rajen of All Loktak Lake Areas Fishermen's Union Manipur agreed with the inference. "At least two lakh people are directly dependant on the lake for fishing. The demand for fish has increased. However, adequate fish is not available in the lake. This is mainly because the migratory fish from Chindwin-Irrawaddy river system to Manipur river system have declined steadily after the barrage came up," said Rajen.

However, he demanded scrapping of the 2006 Act. "We are prevented from carrying traditional fishing equipment inside the lake as per provisions of the Act. Rights of fisherfolk are being curtailed in the name of conservation. We are importing fish from other states to make up for the deficiency," rued Rajen.

By absorbing the annual monsoon flood, the lake plays an important role in flood control and conserves water through the dry months.

In 1986, the Manipur government constituted Loktak Development Authority (LDA) to check the deteriorating condition of the lake and to bring about improvement of the lake ecosystem.

Gradual degradation of the lake and associated swamplands sparked international concern with the water body being included in the Montreux Record in 1993 as a result of problems such as "deforestation in the catchment area, infestation of water hyacinth, and pollution."

Earlier, during the monsoons when the water level would go up, the phumdis would float on the lake surface and in the dry season they would sink to the lake bed and sponge off the nutrients there which were essential for the growth of vegetation.

However, the Ithai barrage (10.7 metres high and 58.8 metres long) for the Loktak hydroelectric project has resulted in "permanent flooding" of the lake.

"Now, there is continuous storage of water in the park area as a result of the barrage and islands float throughout the year even during the winter season. This has prevented nutrient uptake by the islands, thereby reducing their thickness," said Kangabam.

Kangabam and co-authors of the study have flagged this reduction in thickness as a "major concern" for the Sangai.

Oinam also pointed out that water pollution and resulting enrichment of nutrients, fuelled the growth of the aquatic weeds and led to the proliferation of the phumdis at a certain point in time after the barrage came up.

Beset with dwindling water quality and ecosystem, the lake has been battleground between the LDA and a section of fishermen with both parties trading charges on who is responsible for destroying the wetlands.

The fishermen's union claims that in the name of cleaning the lake, the LDA is damaging lake while the authority alleges the fishermen and their floating huts are the ones harming the lake.

According to activist and researcher Ram Wangkheirakpam of Indigenous Perspectives, the Loktak Protection Act requires a "proper review" for the fact that it does not conform to the requirement of the Ramsar Convention nor to the more recent National Wetland Convention Rules 2017.

"It is clear that this Act has been twisted to fit in certain kind of activities while putting traditional users as victims," Wangkheirakpam said.