A wetland is technically defined as:
“An ecosystem that arises when inundation by water produces soils dominated by anaerobic processes, which, in turn, forces the biota, particularly rooted plants, to adapt to flooding.”
The primary factor that distinguishes wetlands from other land forms or water bodies is the characteristic vegetation that adapts to its unique soil conditions. Primarily, wetlands consist of hydric soil, which supports aquatic plants
There are four main kinds of wetlands: marsh, swamp, bog and fen. Sub-types include mangrove, carr, pocosin, and varzea. Some experts also include wet meadows and aquatic ecosystems as additional wetland types.
The Pallikaranai Wetland
Historically, a large part of South Chennai was a flood plain composed of the large Pallikaranai wetland, smaller satellite wetlands, large tracts of pasture land and patches of dry forest.
The Pallikaranai wetland is a freshwater marshland spanning 31 square miles (80 sq Km). It is the Chennai city’s natural primary aquifer recharge system.
The original expanse of the marsh, estimated on the basis of the Survey of India toposheets (1972) and CORONA aerial photographs (1965) was about 5,500 hectares, which has now been reduced to about 600 hectares. Situated next to the Bay of Bengal, about 12.5 miles (20 Km) south of the city centre, it is bounded by Velachery (north), Kovilambakkam (west), Okkiyam Thuraipakkam (east), and Medavakkam (south). It is the only surviving wetland ecosystem of the city and is among the few and last remaining natural wetlands of South India. It is one of the three in the state of Tamilnadu, the other two being Point Calimere and Kazhuveli.
The Pallikaranai wetland is one of the 94 identified wetlands in India under the National Wetland Conservation and Management Programme (NWCMP) of the Government of India that came into operation in 1985–86.
The terrain consists of fresh/saline water bodies, reed beds, mud flats and floating vegetation.
Flora and Fauna
This wetland is literally a treasury of bio-diversity that is almost four times that of Vedanthangal bird sanctuary in the Kancheepuram District of the state of Tamil Nadu, India, 47 miles (75 km) from Chennai where more than 40,000 birds (including 26 rare species), from various parts of the world visit during the migratory season every year.
The Pallikaranai wetland contains several rare and endangered species of plants and animals. It acts as a forage and breeding ground for thousands of migratory birds from various places within and outside the country. Bird watchers opine that the number of bird species sighted in the wetland is definitely more than in the Vedanthangal bird sanctuary.
Figures of the number of fauna and flora found in the Pallikaranai wetland differ among scholars conducting research here.
Among the many quiet contributors to the mapping of India’s natural treasures is Dr. Jayashree Vencatesan, Smithsonian Fellow and researcher, and managing trustee of Care Earth Trust. She obtained a Ph.D. in Biodiversity and Biotechnology from the University of Madras. She is best-known for her research work on biodiversity, and studies wetland ecology.
In 2003, the Tamilnadu State Pollution Control Board assigned her the task of conducting a detailed study of Chennai’s last remaining wetland – the Pallikaranai marsh, which is suffering from degradation caused by human impact. The study had two components — to document the biodiversity and to map the extent of the marsh to define or identify a viable unit of management.
In her work “Protecting wetlands” published on August 10, 2007, Current Science 93 (3): 288–290, she states that the heterogeneous ecosystem of the Pallikaranai marshland supports about 337 species of floras and faunas:
|GROUP||NUMBER OF SPECIES|
Birds, fishes and reptiles are the most prominent of the faunal groups.
However, on August 9, 2013, P. Oppili reported in The Hindu that Dr. K. Venkataraman, Director of Zoological Survey of India (ZSI) while discussing the diversity of species in the marshland, as nine species of amphibians, 21 species of reptiles, 72 species of birds, five species of mammals, 38 species of fish, nine species of shells and 59 species of aquatic and terrestrial insects had been recorded, besides a good number of plankton.
The Pallikaranai wetland is the home to some of the most endangered birds such as the glossy ibis, gray-headed Lapwings and pheasant-tailed Jacana.
Cormorants, darters, herons, egrets, open-billed storks, spoonbills, white ibis, little grebe, Indian Cormorants, darters, herons, egrets, open-billed storks, spoonbills, white ibis, little grebe, Indian moorhen, Black-winged Stilts, purple moorhens, warblers, coots and dabchicks have been spotted in large numbers in the marshland.
The Pallikaranai wetland is also home to some of the most endangered reptiles such as the Russell’s viper.
About 114 species of plants are found in the wetland, including 29 species of grass. These plant species include some exotic floating vegetation such as water hyacinth and water lettuce.
Since 2002, presence of new plants and reptiles have been recorded.
- The Pallikaranai Wetland: Part 2 – The Once Pristine Idyllic Wetland Is Now a Wasteland cum Concrete Jungle! (tvaraj.com)
- February 2, 2014 is World Wetlands Day (tvaraj.com)
- Wetland (en.wikipedia.org)
- Pallikaranai wetland (en.wikipedia.org)
- Study finds 220 fauna species in Pallikaranai (thehindu.com)
Caring for the Earth (thehindu.com)
- Pallikaranai Marshland, Chennai (sudarsanjayasingh.blogspot.in)
- Marsh Melodies (thehindu.com)
- Birds fall prey to dogs at Pallikaranai (thehindu.com)