- The critical floating habitats of the rare sangai, or dancing deer, in Loktak Lake in Manipur, India, are losing out to mushrooming agricultural practices and human settlements, a new study has found.
- The loss of floating islands from the southern and northern part of Loktak is a “major concern,” the study noted, one that could lead to the “destruction of the only floating national park in the world.”
- Much of the changes in the unique floating meadows of Loktak Lake can be attributed to the construction of the Ithai barrage on the Manipur River in 1979 for a hydroelectric project, researchers say.
The iconic Loktak Lake in the Indian state of Manipur is famous for its unique floating islands made of mats of soil, plants and organic matter at various stages of decomposition, all naturally bundled together. One of the largest of these floating island meadows is the last natural refuge of the rare sangai (Rucervus eldii eldii), also called the brow-antlered or dancing deer. But these floating habitats, locally called phumdis, are losing ground to mushrooming agricultural practices and human settlements, a new study published in Environmental Monitoring and Assessment reports.
These changes in land use patterns can be linked to the construction of the Ithai barrage on the Manipur River in 1979 for the Loktak hydroelectric project, the study notes.
Scientists looked at satellite data from 1977 to 2015 (from the pre-barrage to post-barrage period) and found that the area of phumdis had declined over the years.
“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,” lead author Rajiv Kangabam, a postdoctoral fellow at Assam Agricultural University, told Mongabay-India.
The 247-square-kilometer (95-square-mile) Loktak Lake is listed as a Ramsar Wetland of International Importance, cradled in the floodplain of the Manipur River. About one-and-a-half hours’ drive from Manipur’s capital, Imphal, the lake and the resident sangais are the principal attractions for travelers.
Loktak is also northeast India’s largest freshwater lake, and like a jewel in a crown, it is positioned almost centrally in the state of Manipur, which shares a border with Myanmar. Teeming with a diverse range of flora and fauna, the lake ecosystem lies within the Indo-Burma Biodiversity Hotspot.
A source of water for hydropower generation, irrigation and drinking water, the lake has become a hotbed of tourism and related developmental activities. The ancient water body has also nurtured fishing and agriculture, shaping the region’s socio-economy. According to the folklore of the Meitei, Manipur’s culturally dominant indigenous group, the lake was home to India’s very own Loch Ness monster, a mythical horned python called Poubi Lai.
Now, the wetland system is in the crosshairs of development and tradition, with environmental conflicts underpinned by changes largely ascribed to the nearly 40-year-old Ithai barrage.
The floating national park and the dancing deer are under threat. Video by Kartik Chandramouli/Mongabay.
Deer that dance on the world’s only floating park
The sangai was believed to have gone extinct until a remnant population was discovered in the early 1950s. Today, only about 260 of the deer remain, according to the forest department, while wildlife biologists from the Wildlife Institute of India put the figure at fewer than 100 adult breeding individuals.
Ubiquitous in folk art and lore, the sangai is also the state animal of Manipur. The emblematic species lends its name to the annual Sangai festival organized by the Manipur government each November.
The dancing deer are concentrated within the 40-square-kilometer (15-square-mile) Keibul Lamjao National Park (KLNP), a large floating meadow on the southern rim of the lake, and the only known floating national park in the world. It was created in 1977 to conserve the last of the sangais and the lake biodiversity within the phumdi ecosystem.
Phumdis, part submerged, part floating, are the elements that make the Loktak ecosystem unique. These islands are also critical in supporting the weight of the sangai (also called dancing deer for their dainty gait) as they negotiate their way through the floating islands. Two-thirds of the saucer-shaped lake is dotted with these floating meadows.
But the loss of floating islands in the southern and northern part of Loktak is a “major concern,” the study noted, one that could lead to the “destruction of the only floating national park in the world.” It indicates an increase in open water area, human population and agricultural area.
In terms of land use changes, the highest loss reported in the study is in phumdis with thin vegetation (49 square kilometers, or 19 square miles), followed by phumdis with thick vegetation (9 square kilometers, or 3.5 square miles), while there was an overall increase in open water bodies (27 square kilometers, or 10 square miles), agricultural areas (25 square kilometers, or 9.7 square miles) and settlements (5.8 square kilometers, or 2.2 square miles).
Kangabam said the rapid growth in human settlements was associated with the submergence of vast swaths of agricultural lands, a fallout of the construction of the Ithai barrage.
“It was estimated that 20,000 hectares of arable land” — about 49,000 acres, but unofficially up to four times larger — “was submerged, resulting in the loss of employment of the local people,” he said. “This led to increase in human pressure on the lake resources, leading to increase in human settlement and a high demand for fish.”
Loktak Lake over the years. Slide to view the disappearing phumdis.
The study authors also identified the need for proper implementation of the Manipur Loktak Lake (Protection) Act of 2006 to guide the increasing human activity in the lake area, in order to protect Loktak through sustainable management and conservation of the rich biodiversity.
The analysis also underscored the need for regular monitoring and implementing proper land use practices in and around the lake to restore the degraded ecosystem plagued by pollution and an altered aquatic regime.
“There is a need to balance ecological protection and human needs,” Kangabam said. “Without provision of alternative livelihood options, the human pressure on the lake will go up and this will be disastrous for the lake.”
Oinam Rajen, of the All Loktak Lake Areas Fishermen’s Union Manipur (ALLAFUM), agreed. At least 200,000 people are directly dependent on the lake for fishing, he said, but the supply isn’t enough to meet the demand.
“This is mainly because the migratory fish from Chindwin-Irrawaddy river system to Manipur river system have declined steadily after the barrage came up. Human settlements have gone up and so has paddy cultivation,” Rajen said.
For his part, he called for the 2006 Act to be scrapped.
“This is compounded by the fact that we are prevented from carrying traditional fishing equipment inside the lake as per provisions of the Act,” he said. “Rights of fisherfolk are being curtailed in the name of conservation. We are importing fish from other states to make up for the deficiency.”
Around 9 percent of the total population of Manipur, or about 200,000 people, dwell in 12 towns and 52 settlements in and around the lake, earlier dubbed a “lifeline” for the people of Manipur.
By absorbing the annual monsoon runoff, the lake plays an important role in flood control and conserves water through the dry months.
The cultivation of rice is the traditional practice in the phumdis, said Kangabam, adding that it’s also a source of livelihood for the rural fishermen who live in the surrounding villages and also on the phumdis in traditional huts called khangpok. Some rice varieties can also grow in the submerged conditions of the phumdis.
Resembling green rings, man-made aquaculture ponds called athaphum, created by segregating portions of phumdis, are used for fishing. Fresh and fermented fish hold sway in the Manipuri diet.
The operationalization of the Ithai barrage in 1983 for hydroelectric power generation and irrigation purposes, without proper planning, has been linked to a multitude of problems shrouding the once pristine lake.
In 1986, the Manipur government constituted the Loktak Development Authority (LDA) to check the deteriorating condition of the lake and improve the lake ecosystem alongside boosting development in the field of fisheries, agriculture and tourism while conserving the catchment area.
Declines in fish resources affecting the livelihoods of the fisher communities; enhanced soil erosion leading to wetland sedimentation due to shifting cultivation and loss of vegetal cover in the catchment area; reduction in water holding capacity of wetlands as a consequence of siltation; encroachments and prolific growth of aquatic vegetation — these are all some of the problems listed by the LDA on its website.
The gradual degradation of the lake and associated swamplands has 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.”
Serving as the receptacle for about 30 rivers and streams, Loktak Lake has turned into a dumping ground for the untreated waste that is drained into it from these water bodies, including the highly polluted Nambul and Nambol rivers. The barrage is the only outlet for the rivers.
“In addition, the establishment of the Ithai barrage has disrupted the normal flushing pattern of the lake and also interfered with the natural process of synthesis and breakdown of the phumdis,” Kangabam said, referring to the unique sink-and-swim cycle of the floating islands critical to their growth and function.
In previous years, during the monsoons when the water level would go up, the phumdis would float on the lake surface; 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.
When the rains returned, the islands, with their nutrient-laced plant roots, would float again. However, that cycle is now broken, as the Ithai barrage 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 [dry] winter season,” Kangabam said. “This has prevented nutrient uptake by the islands, thereby reducing their thickness.”
Kangabam and co-authors of the study have flagged this reduction in thickness as a “major concern” for the sangai.
Rajen said water pollution, and the resulting enrichment of nutrients, had fueled the growth of aquatic weeds and led to the proliferation of the phumdis at a certain point in time after the barrage came up.
“Before the construction of the Ithai barrage, the phumdis would proliferate, and during the rainy season, they would be discharged from the lake to the Manipur River, thereby maintaining the population,” Kangabam said. “But the construction of Ithai barrage blocked the passage and changed the flushing mechanism.”
Rajen said it was due to the efforts of the fishing communities that the phumdis were prevented from pervading the entire lake.
“We took it upon ourselves to clear off the excess phumdis. Since time immemorial, the fishing communities have maintained the lake,” he said.
The subsequent decrease of phumdis from the central part of the lake is due to the removal of the biomass by authorities to maintain the water quality, Kangabam said.
“The proliferation of phumdis has decreased from the central part. In the northern and southern part the phumdis remain as it is. But human activities have increased in those parts so overall phumdi area has gone down,” Kangabam said.
Bioprospecting for bacteria in the phumdis
Saving the lake is also advantageous for bioprospecting of potential bacteria for their use in agriculture as plant growth promoters or biofertilizers.
Recently, a team of scientists isolated 26 bacterial strains from the phumdi sediment and lake water, which they say can be used in sustainable agriculture.
These isolates from Loktak Lake have the potential to be used for the production of industrially important enzymes and in agriculture as plant growth promoters (such as siderophores, indole acetic acid or IAA), said Milind Mohan Naik of Goa University’s Department of Microbiology, in a study published in Current Science.
Among the 26 Loktak bacterial isolates, for instance, Enterobacter tabaci strain KSA9 is found to produce siderophore, IAA, which is involved in nitrogen fixation, phosphate solubilization and ammonia production.
The presence of plant growth promoting microorganisms was expected from phumdi sediment, due to the fact that local people have long used phumdi sediment as a biofertilizer in agriculture. It exhibits good plant growth promotion that may be attributed to the presence of bacteria. But that bacterial diversity is facing threats due to the overall disturbance of the ecosystem.
Beset by declines in both the water quality and the ecosystem, Loktak Lake has become a battleground between the Loktak Development Authority and a section of fishermen, with both parties trading charges on who is responsible for destroying the wetlands.
The fishermen’s union says that in the name of cleaning the lake, the LDA is damaging the lake; the authority, meanwhile, says the fishermen and their floating huts are the ones doing the harm.
“Enforcing the Manipur Loktak Lake (Protection) Act, the government … began to clear the lake of human settlements in 2011,” Rajen said. At the time, he said, there were 1,100 huts built on the phumdis; 777 of them were burned and hundreds of families were evicted since then. “The fisherfolk were dubbed ‘occupiers,’” Rajen said.
According to activist and researcher Ram Wangkheirakpam of the NGO Indigenous Perspectives, the Loktak Protection Act requires a “proper review,” given that it doesn’t conform to the requirements of the Ramsar Convention or to the more recent National Wetland Convention Rules 2017.
“The Act does not cover the whole of the lake,” Wangkheirakpam said. “It excludes the water sports area at Takmu that they have carved out as also the Keibul Lamjao National Park. There are two resorts, and two hotels coming up, they are also trying to evict some 450 families for the resort in the name of tourism promotion in the state.” He said the Loktak Development Authority was a failed institution and required a comprehensive revamping of its constitution and composition.
“It is clear that this Act has been twisted to fit in certain kind of activities while putting traditional users as victims,” Wangkheirakpam said. “Traditional livelihood options have somehow been sidelined while non-traditional activities are being promoted. The local community must be included in conserving this wetland.”
Kangabam, R. D., Selvaraj, M., & Govindaraju, M. (2018). Spatio-temporal analysis of floating islands and their behavioral changes in Loktak Lake with respect to biodiversity using remote sensing and GIS techniques. Environmental monitoring and assessment, 190(3), 118.
Salkar, K., Gadgil, V., Dubey, S. K., Naik, M. M., & Pandey, R. R. (2018). Largest freshwater lake ‘Loktak’ in Manipur needs urgent conservation. Indian Academy of Sciences.