Phumdi
Encyclopedia
Phumdis are a series of floating island
Floating island
A floating island is a mass of floating aquatic plants, mud, and peat ranging in thickness from a few inches to several feet. Floating islands are a common natural phenomenon that are found in many parts of the world. They exist less commonly as a man-made phenomenon...

s, exclusive to the Loktak Lake
Loktak Lake
Loktak Lake, the largest freshwater lake in India, also called the only Floating lake in the world due to the floating phumdis on it, is located near Moirang in Manipur state, India. The etymology of Loktak is Lok = "stream" and tak = "the end"...

 in Manipur
Manipur
Manipur is a state in northeastern India, with the city of Imphal as its capital. Manipur is bounded by the Indian states of Nagaland to the north, Mizoram to the south and Assam to the west; it also borders Burma to the east. It covers an area of...

 state, in northeastern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. 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 square kilometre. This mass constitutes the world’s largest floating park, named Keibul Lamjao National Park
Keibul Lamjao National Park
The Keibul Lamjao National Park is a national park in the Bishnupur district of the state of Manipur in India. It is in area, the only floating park in the world, located in North East India, and an integral part of Loktak Lake....

. The park was formed to preserve the endangered Eld's Deer
Eld's Deer
Eld's Deer , also known as the Thamin or Brow-antlered Deer, is an endangered species of deer indigenous to southeastern Asia. The species was first discovered by westerners in Manipur in India in 1839. The original scientific name Cervus eldi was coined in 1844 in honour of Lt. Percy Eld – a...

 subspecies, called Sangai
Sangai
The Sangai is an endemic, rare and endangered Brow-antlered deer found only in Manipur, India. Its common English name is Manipur Brow-antlered Deer and the scientific name, Rucervus eldi eldi McClelland. It lives in the marshy wetland in Keibul Lamjao about 45 km from Imphal...

 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
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

 has caused proliferation of the phumdis in the lake.

Traditional practice

Although phumdi vegetation has existed for centuries, it was not until 1886 that the Manipur Gazetteer recorded that wetlands with floating islands were used by inhabitants for fishing. Before the Itahi barrage was constructed in 1986, 207 khangpoks (huts or sheds) were reported on the phumdis, but after the dam was completed in 1999, the Loktak Development Authority (LDA) reported 800 such structures. Many of the huts are reported to have been converted into permanent dwellings and about 4,000 people live in these floating huts, earning their living as fishermen. The huts are constructed using plastic ropes, heavy rocks, wood, bamboo, zinc plates and iron rods. Athapums, artificial circular phumdis, which were built by the villagers as enclosures for fish farming, are present on the lake, and this aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

 has caused further proliferation of the phumdis. A tourist lodge has been built on one of the phumdis in Sandra Island.

Ecological composition

The floating mass of matted vegetation, organic debris, and soil that constitutes a phumdi has a thickness that varies from a few centimetres to two metres. Its humus is black in colour and porous, with a spongy texture. Only 20% of a phumdi's thickness floats above the water surface; the other 80% remains submerged. Before the construction of the Loktak Hydroelectric Project, the park area containing phumdis was merely marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

y land, but since the commissioning of the project, two ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s have emerged. One, the body of open water, covers one-third of the area and the other, the phumdi, covers the remaining two-thirds.
The life-cycle of the phumdis has generally been subject to seasonal variation. During the monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...

 season when the water level is high, the phumdis float, but during the dry season, as the water level falls, the phumdis touch the lake bed and absorb nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

s from it. When the wet season returns, they again float, and the biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

, which has enough nutrients stored in the plants' roots, survives. However, the contemporary situation, with high water levels in the lake throughout the year, has meant that the process of 'feeding' on lake–bottom nutrients has been seriously disturbed, resulting in a loss of biomass and a thinning of the islands each year. In January 1999, it was reported that a large section of phumdi in the north of the park had shattered into pieces and drifted away from the park area, theatening the habitat of the Sangai
Sangai
The Sangai is an endemic, rare and endangered Brow-antlered deer found only in Manipur, India. Its common English name is Manipur Brow-antlered Deer and the scientific name, Rucervus eldi eldi McClelland. It lives in the marshy wetland in Keibul Lamjao about 45 km from Imphal...

.
Changes in the water regime due to the construction of the Ithai barrage across the Manipur River have caused changes in the vegetation composition of the phumdis. A study was instituted, from October 2005 to July 2006, to record the vegetation composition and productivity of phumdis in areas of ranging thickness, water depth and soil pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

, accumulating data in both summer and winter. The study recorded 83 plant species of 21 families (Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

and Cyperaceae
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

formed the dominant families); 81 species were recorded in summer and 48 in winter.
The Diversity indices
Simpson index
Simpson's diversity index is one of a number of diversity indices, used to measure diversity. In ecology, it is often used to quantify the biodiversity of a habitat. It takes into account the number of species present, as well as the relative abundance of each species...

 of the plant species were recorded; they were a richness of 48, diversity of 0.29 and evenness of 0.47 in summer. In winter, the respective figures were 81, 0.17 and 0.52. Species richness was found to be different in 48 samples of thin phumdis, 53 samples of thick phumdis and 14 samples on hard ground. The eight plant communities identified during winter and summer were Capillipedium
Capillipedium
Capillipedium is a genus of grass in the Poaceae family.-Species:*Capillipedium annamense*Capillipedium assimile*Capillipedium duongii*Capillipedium filiculme*Capillipedium huegelii*Capillipedium kuoi...

, Leersia
Leersia
Leersia is a genus of true grasses which includes species known generally as cutgrasses. There are about 17 species native to tropical and warm temperate areas of the Americas and Eurasia...

 hexandra
, Oenanthe javanica
Oenanthe javanica
Japanese parsley or Chinese celery is a plant of the water dropwort genus originating from East Asia.While many other species of water dropwort are extremely toxic, Oenanthe javanica is edible, and is cultivated in the People's Republic of China, India, Japan, Korea, Malaysia, Thailand , the...

, Phragmites
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...

 karka
, Kyllinga
Kyllinga
Kyllinga is genus of flowering plants in the sedge family known commonly as spikesedges. They are native to tropical and warm temperate areas of the world, especially tropical Africa. These sedges vary in morphology, growing to heights from 2 centimeters to a meter and sometimes lacking rhizomes...

 triceps
, Pteridium aquilinum
Bracken
Bracken are several species of large, coarse ferns of the genus Pteridium. Ferns are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells . Brackens are in the family Dennstaedtiaceae, which are noted for their large, highly...

, Zizania latifolia
Wild rice
Wild rice is four species of grasses forming the genus Zizania, and the grain which can be harvested from them. The grain was historically gathered and eaten in both North America and China...

and Persicaria perfoliata. Zizania latifolia recorded the highest productivity with (13.90 ± 5.01) g/m2 for winter and (102.96 ± 26.03) g/m2 for summer. Greater productivity was recorded in summer (65.96 g/m2) than winter (15.76 g/m2). Variation of productivity of annuals and perennials were noted according to seasons and type of phumdis.

Wildlife

The largest of all the phumdis in the lake is situated in the southeastern region of the Loktak Lake, which forms the Keibul Lamjao National Park
Keibul Lamjao National Park
The Keibul Lamjao National Park is a national park in the Bishnupur district of the state of Manipur in India. It is in area, the only floating park in the world, located in North East India, and an integral part of Loktak Lake....

. This park is the last natural refuge of the endangered Manipur brow-antlered deer (Cervus eldi eldi), locally known as the Sangai
Sangai
The Sangai is an endemic, rare and endangered Brow-antlered deer found only in Manipur, India. Its common English name is Manipur Brow-antlered Deer and the scientific name, Rucervus eldi eldi McClelland. It lives in the marshy wetland in Keibul Lamjao about 45 km from Imphal...

, one of the three sub species of the eldi's deer listed as an endangered species by the International Union for Conservation of Nature.

Apart from the brow-antlered deer, which is the flagship species of the park, other fauna found in the park are mammals, reptiles, and migratory and resident avifauna
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 species.

Mammal species consist of Hog deer
Hog Deer
The Hog Deer is a small deer whose habitat ranges from Pakistan, through northern India, to mainland southeast Asia...

 (C. porcinus), Wild boar (Sus scrota), Large Indian Civet
Large Indian Civet
The Large Indian Civet is a member of the Viverrid family native to Southeast Asia. In 2008, the IUCN classified the species as Near Threatened, mainly because of the known heavy trade as wild meat.- Characteristics :...

s (Viverra civetta, Viverricula indica), common otter (Lutra lutra), fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...

, jungle cat
Jungle Cat
The jungle cat is a medium-sized cat and considered the largest remaining species of the wild cat genus Felis. The species is also called the swamp lynx but is not closely related to the lynxes....

, golden cat
Golden cat
A golden cat is a medium-sized wild cat belonging to either the genus Catopuma or Profelis. There are three species of golden cats:* African Golden Cat, Profelis aurata* Asian Golden Cat, Catopuma temminckii* Bay Cat, Catopuma badia...

, Bay bamboo rat
Bamboo rat
The bamboo rats are four species of rodents of the subfamily Rhizomyinae. They are the sole living representatives of the tribe Rhizomyini. All are found in the eastern half of Asia.The species are:...

, musk shrew, common shrew
Common Shrew
The Common Shrew or Eurasian Shrew, Sorex araneus, is the most common shrew, and one of the most common mammals, throughout Northern Europe, including Great Britain, but excluding Ireland. It is long and weighs , and has velvety dark brown fur with a pale underside. Juvenile shrews have lighter...

, flying fox, and Sambar (Cervus unicolor).

Reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

 species found in the park are the Keel back Tortoise
Tortoise
Tortoises are a family of land-dwelling reptiles of the order of turtles . Like their marine cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise...

, Viper
Viperidae
The Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, Ireland, Madagascar, Hawaii, various other isolated islands, and above the Arctic Circle. All have relatively long, hinged fangs that permit deep penetration and injection of venom. Four...

, Krait, Cobra
Cobra
Cobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...

, Water cobra, krait (banded) Bungarus fasciatus
Bungarus fasciatus
The Banded krait is a species of genus Bungarus found in Indian Sub-continent, North Asia and Southeast Asia. It is one of the largest kraits with a maximum length up to .- Description :B...

, Asian rat snake (Beauty rat snake
Beauty rat snake
The Beauty Rat Snake is a species of long, slender, semi-arboreal snakes that are native to Asia. Their average length is about 5-7 feet, with an unofficial record of slightly under 10 ft...

), Russels’ viper (Daboia
Daboia
Daboia is a monotypic genus of venomous Old World viper. The single species, D. russelii, is found in Asia throughout the Indian subcontinent, much of Southeast Asia, southern China and Taiwan...

), checkered garter snake, Python
Python (genus)
Python, from the Greek word , is a genus of non-venomous pythons found in Africa, Asia and Australia. Currently, 7 species are recognised. A member of this group, P. reticulatus, is among the longest snakes known.-Geographic range:...

 and Common Lizard (Viviparous Lizard). Python molurus is an endangered species found in the park.

Prominent bird species seen in the park are both migratory and resident avifauna
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 species. Some of the avifauna are the East Himalayan pied Kingfisher
Kingfisher
Kingfishers are a group of small to medium sized brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species being found in the Old World and Australia...

, Black kite
Black Kite
The Black Kite is a medium-sized bird of prey in the family Accipitridae, which also includes many other diurnal raptors. Unlike others of the group, they are opportunistic hunters and are more likely to scavenge. They spend a lot of time soaring and gliding in thermals in search of food. Their...

, lesser sky-lark
Lark
Larks are passerine birds of the family Alaudidae. All species occur in the Old World, and in northern and eastern Australia; only one, the Shore Lark, has spread to North America, where it is called the Horned Lark...

, Northern Hill Myna
Hill Myna
The Common Hill Myna , sometimes spelled "mynah" and formerly simply known as "Hill Myna", is the myna bird most commonly seen in aviculture, where it is often simply referred to by the latter two names. It is a member of the starling family , resident in hill regions of South Asia and Southeast Asia...

, 5) Burmese Pied Myna, North Indian black Drongo
Drongo
The drongos are a family of small passerine birds of the Old World tropics, the Dicruridae. This family was sometimes much enlarged to include a number of largely Australasian groups, such as the Australasian fantails, monarchs and paradise flycatchers...

s, Lesser eastern jungle crow
Crow
Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...

, Yellow headed wagtail
Wagtail
The wagtails form the passerine bird genus Motacilla. They are small birds with long tails which they wag frequently. Motacilla, the root of the family and genus name, means moving tail...

, Spotbill duck, Blue-winged teal
Blue-winged Teal
The Blue-winged Teal is a small dabbling duck from North America.-Description:The Blue-winged Teal is long, with a wingspan of , and a weight of . The adult male has a greyish blue head with a white facial crescent, a light brown body with a white patch near the rear and a black tail. The adult...

, Ruddy Shell duck, Threatened Hooded crane
Hooded Crane
The Hooded Crane, Grus monacha is a small, dark crane. It has a grey body. The top of the neck and head is white, except for a patch of bare red skin above the eye...

, Burmese sarus Sarus Crane
Sarus Crane
The Sarus Crane is a large non-migratory crane found in parts of the Indian Subcontinent, Southeast Asia and Australia. The tallest of the flying birds, standing at a height of up to 1.8 m , they are conspicuous and iconic species of open wetlands...

 , Indian white breasted water hen and Crimson-breasted pied wood pecker.

Environmental issues

The proliferation of phumdis, coupled with severe infestation of the lake by water hyacinth
Water hyacinth
The seven species of water hyacinth comprise the genus Eichhornia. Water hyacinth are a free-floating perennial aquatic plant native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in...

, has substantially impeded water circulation and caused an increase in siltation and deposit of pollutants in the lake ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

. The building materials used to build huts on the phumdi blocks sunlight from reaching the lower depths of the lake water, which has resulted in formation of vertical profiles of the lake water body and decomposition. Further, pesticides and insecticides are used for catching fish or as insect repellent. Degradation is in the form of benthal, which, as it decays, releases toxic gases such as methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

, hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

, and reduces dissolved oxygen
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...

 (DO). This causes the lake water to degenerate into a eutrophic condition, creating a dead water zone called the hypolimnion
Hypolimnion
The hypolimnion is the dense, bottom layer of water in a thermally-stratified lake. It is the layer that lies below the thermocline.Typically the hypolimnion is the coldest layer of a lake in summer, and the warmest layer during winter...

. Above the hypolimnion is a thin layer, known as epilimnion
Epilimnion
The epilimnion is the top-most layer in a thermally stratified lake, occurring above the deeper hypolimnion. It is warmer and typically has a higher pH, but lower dissolved oxygen concentration than the hypolimnion....

, where fish survive to some degree. The benthal is becoming increasingly thick, causing not only pollution of the lake water, but an increase in the shallow part of the lake.

It has been reported that the construction of Ithai Barrage has altered the Loktak Lake and its ecosystem. Siltation has reduced the water holding capacity and has consequently had a negative impact on the power generation capacity at the Loktak Hydro Electric Power Project. Thinning of the phumdi in the Keibul Lamjao area has affected the habitat of the Sangai
Sangai
The Sangai is an endemic, rare and endangered Brow-antlered deer found only in Manipur, India. Its common English name is Manipur Brow-antlered Deer and the scientific name, Rucervus eldi eldi McClelland. It lives in the marshy wetland in Keibul Lamjao about 45 km from Imphal...

, and other aquafauna, avifauna and flora are on the decline; the 35 species (5 mammals, 3 birds, 9 reptiles, 3 amphibians, 12 fishes, 2 molluscs
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...

 and 1 annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...

) are reported to be disappearing gradually.
It is also reported that the soil of the park formed by the phumdis is highly acidic, with unsuitable pH conditions for many species of plants to grow and flourish. Further, the acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ity of the soil has also adversely affected the fish breeding farms. Recent reports indicate that locals are slicing the phumdis into sizeable pieces and towing them with canoes to sell to fish culture owners.

A scientific study of the water quality parameters of physico-chemical and microbiological characteristics and role of phumdis in the Loktak Lake has been conducted by collecting surface water samples on monthly basis from 15 stations, representing 5 zones; northern, western, eastern, middle and southern. The test results indicated that water quality
Water quality
Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...

 in the phumdi area was poor in the northern and southern zones of the lake; test results indicated low dissolved oxygen, low pH (normal range for pH in surface water systems is 6.5 to 8.5) high CO2 and high Biochemical Oxygen Demand
Biochemical oxygen demand
Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for...

 (BOD) but the water quality was good in the open water area. Assessment of the total nitrogen content of the macrophyte
Macrophyte
A macrophyte is an aquatic plant that grows in or near water and is either emergent, submergent, or floating. In lakes macrophytes provide cover for fish and substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife....

 species of phumdis indicated that the following were present in descending order: Salvinia
Salvinia
Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Antonio Maria Salvini, a 17th Century Italian scientist. The genus was published by Séguier, in Pl. Veron. 3: 52. 1754. About ten species exist....

 natans
(1.8%), Zizania latifolia
Wild rice
Wild rice is four species of grasses forming the genus Zizania, and the grain which can be harvested from them. The grain was historically gathered and eaten in both North America and China...

(1.6%), Capillipedium sp. (1.3%), Brachiaria mutica (1.2%), Cyperus
Cyperus
Cyperus is a large genus of about 600 species of sedges, distributed throughout all continents in both tropical and temperate regions. They are annual or perennial plants, mostly aquatic and growing in still or slow-moving water up to 0.5 m deep. The species vary greatly in size, with small species...

 brevifolius
(1.2%), Echinochloa stagnina
Echinochloa stagnina
Echinochloa stagnina is a species of Echinochloa widespread in tropical Africa and Asia, with an invasive status in many Pacific islands....

(1.0%), Phragmites
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...

 karka
(1.0%) and Hedychium
Hedychium
Hedychium is a genus of perennial plants native to tropical Asia and the Himalayas, commonly growing to between 120 and 180 cm tall. Common names include garland flower, ginger lily, and kahili ginger...

 coranarium
(0.94%). The test results confirmed the fact that the phumdis were efficient in absorbing nutrients from the lake water. However, they deteriorated water quality due to reduced light penetration and accumulation of organic matter in the lake ecosystem.

Management strategies

A detailed study has been conducted by the Loktak Development Authority (LDA) in collaboration with Wetlands International
Wetlands International
Wetlands International is a global organisation that works to sustain and restore wetlands and their resources for people and biodiversity. It is an independent, not-for-profit, global organisation, supported by government and NGO membership from around the world...

South Asia
South Asia
South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...

, supported by the India–Canada Environment Facility, implementing a project on Sustainable Development and Water Resources Management of the Loktak Lake. The project addresses the issues relating to water management, sustainable fisheries
Sustainable fisheries
Sustainability in fisheries combines theoretical disciplines, such as the population dynamics of fisheries, with practical strategies, such as avoiding overfishing through techniques such as individual fishing quotas, curtailing destructive and illegal fishing practices by lobbying for appropriate...

 development, community participation and development, catchment area treatment and conservation of wildlife. The Planning Commission of the Government of India, decided in September 2008 that these policies would be implemented over a period of 5–6 years at an estimated cost of over Rs500 crores (US$100 million), and extended the area under management to also incorporate the water of Nambul and other rivers and their tributaries, which are primarily responsible for polluting the Loktak Lake.

In order to resolve the problem of the excessive growth of phumdis that affects the lake ecosystem and local community, a study sponsored by the India–Canada Environment Facility was undertaken by the Tata Energy Research Institute (TERI) to examine efficient ways of converting phumdis into briquette
Briquette
A briquette is a block of flammable matter used as fuel to start and maintain a fire. Common types of briquettes are charcoal briquettes and biomass briquettes.-Constituents of charcoal briquettes:...

s as fodder and fuel pellets, which could be used to meet both energy demands within the region. Two options for the biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

 conversion were studied. The first involved making briquettes of vegetative part of phumdis for use as fodder while the second proposed to pelletise the lower part of phumdis for use as fuel. The study observed that phumdis have nutritional potential as feed material due to its higher crude fibre and crude protein content, but the inorganic
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 content in the root and mat zone was found to be unsuitable for the purpose. The second option of making briquettes from the upper vegetative portion of the phumdis by mixing 12% de-oiled rice bran
Bran
Bran is the hard outer layer of grain and consists of combined aleurone and pericarp. Along with germ, it is an integral part of whole grains, and is often produced as a by-product of milling in the production of refined grains. When bran is removed from grains, the grains lose a portion of their...

 was found to be feasible for using them as fodder. The lower portion, which was densified to make fuel pellets, was found to be suitable for use as fuel. Such pellets were found to have an average calorific value
Heat of combustion
The heat of combustion is the energy released as heat when a compound undergoes complete combustion with oxygen under standard conditions. The chemical reaction is typically a hydrocarbon reacting with oxygen to form carbon dioxide, water and heat...

 of 3,400 calories per kilogram (14,200 kJ/kg) with ash content of 27%. Cost economics were worked out and the study had found it to be “an economically viable and an attractive proposition for the benefit of local population.” The study concluded that extraction of phumdi from the lake could also generate income for the local people who are dependent on the lake for their livelihood. Such a step would protect the lake from the adverse effects of proliferation of phumdis and maintain the ecological balance of the lake, thus converting the waste into wealth. The Planning Commission has also concurred with project proposals to engage interested individuals and private enterprises to begin the commercial venture of manufacturing compost from the phumdis and thus improve the environment of the Keibul Lamjao National Park. The project also envisages removal of 3630 artificial phumdis and compensation to their owners; this is reported to have been implemented.

Another method adopted in the past to tackle the phumdis was by way of diverting them towards the Khordak River. However, as this approach had not been very successful, the State Government planned to construct a canal at Tera Khunou Khong Ahanbi to divert the phumdis to Manipur River. Other methods adopted by the Loktak Development Authority (LDA) to control phumdis and water hyacinth include introducing weevils for the biological control of water hyacinth, which was carried out in collaboration with the Horticulture Institute of Bangalore
Bangalore
Bengaluru , formerly called Bengaluru is the capital of the Indian state of Karnataka. Bangalore is nicknamed the Garden City and was once called a pensioner's paradise. Located on the Deccan Plateau in the south-eastern part of Karnataka, Bangalore is India's third most populous city and...

. Reports have shown this to be an effective method in controlling water hyacinth.

A lake restoration plan based on a decentralised bioreactor
Bioreactor
A bioreactor may refer to any manufactured or engineered device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical process is carried out which involves organisms or biochemically active substances derived from such organisms. This...

 system to eliminate the organic load that enters the lake in the form of non-point and point source pollutants has also been mooted. Phumdis could be harvested in a sustainable manner by conversion into fuel and compost by installing ‘Plug Flow Bioreactors’ in a modular manner around the lake perimeter. Laboratory tests of key species of phumdis have proved its potential to produce biogas
Biogas
Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and kitchen waste can be converted into a gaseous fuel called biogas...

. The bioreactors could also be used to treat sewage and thus arrest flow of organic matter into the lake.

In a recent workshop organized by the LDA on "Management of Phumdis" in the Loktak Lake, which involved presentations by locals, the emphasis was on the need to open the barrage for eight months per year (January, April and June–September) to clear the phumdis, control floods and wash away the silt and waste that had accumulated over time. The LDA is also implementing action plans that are economically viable and technically feasible which would result in livelihood enhancement such as evolving an attractive resettlement plan for the phumdi dwellers backed by remunerative livelihood programs and examine the introduction of fishing nets instead of Athapum, the circular shaped Phumdis floating in the lake, planted or cultured artificially for catching fish.
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