A wetland is an area of land that is saturated with water - either all through the year or for varying periods of time during the year.
Sunlight from the sun can penetrate the lower layers of a wetland, owing to its shallow depth. This unique feature facilitates photosynthetic activities, making these water bodies one of the most productive
ecosystems on the planet.
According to the Ramsar Convention on Wetlands , wetlands are “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres.”
Wetlands are diverse in terms of how they form, their geographical location, the biodiversity that thrives in and around them, the nature of soil around/beneath them and in the various ways in which they function. They not only support innumerable plant and animal species but are also indispensable for humans, whose water requirements are in one way or the other met by these systems.
In India, wetlands include most of the natural water bodies - lakes, coastal lagoons, mangroves, peat land and coral reefs. There are also numerous manmade wetlands in our country such as ponds, farm ponds, irrigated fields, sacred groves, salt pans, reservoirs, gravel pits, sewage farms and canals.
Of the hundreds of wetlands in India, only 26 wetlands have been designated as Ramsar Sites, wetlands considered to be of international importance under the Ramsar Convention.
India has about 757.06 thousand wetlands with a total wetland area of 15.3 m ha, accounting for nearly 4.7% of the total geographical area of the country.
Wetlands are amongst the most productive ecosystems on Earth! Diverse and unique habitats in themselves, they provide a range of important goods and services. This makes them invaluable! Here’s what they do for us:
Water supply – Tanks, ponds, lakes and reservoirs provide water for irrigation, domestic needs, fisheries and recreational uses. They also help recharge groundwater and ensure regular water supply for human and livestock consumption.
Aqua Culture – Wetlands serve as breeding grounds for a large variety of aquatic life. They provide livelihood options to a large number of fishermen families which are involved in fishing, both organized and unorganized.
Pollution control – Wetlands act as a sink for pollutants in agricultural and urban areas. They retain contaminants and keep them from running into rivers and streams. Ideally, a well-designed manmade wetland should be used to abate pollution since a natural wetland has the risk of degrading.
Flood control – Wetlands help reduce the impact of flooding by absorbing water and reducing the speed at which flood water flows. While doing this, they trap suspended nutrients which make the floodplains (land next to a river or lake) highly fertile.
Wetlands are considered to be the natural substitutes for conventional flood control investments such as dykes, dams and embankments.
Carbon sequestration – Sequestration is a natural or artificial process by which carbon dioxide is removed from the atmosphere and held in solid or liquid forms. Swamps, mangroves, peat lands, mires and marshes are storehouses of carbon and help keep the carbon cycle in check.
Biodiversity hotspots – Wetlands support innumerable species of plants and animals. Wetlands are also important breeding areas for wildlife and provide refuge to a number of migratory birds. Aquatic plants, fish, amphibians, phytoplankton, mollusks and birds are some of the various species dependent on them.
Some of the migratory birds that visit our wetlands every year are Red Crested Pochards, Brooks Leaf Warbler, White Tailed Lapwing, Orphean Warbler, Sind Sparrow, Rock Eagle Owl and Great White Pelicans.
In Asia alone, 5000 sq km of wetland area is lost to agriculture, dam construction and other uses every year.
India has lost 50 % of its wetlands in the past 100 years!
"According to a survey conducted by Wildlife Institute of India:
-70 to 80% of freshwater marshes and lakes in the Gangetic flood plains have been lost during the last 50 years.
-The mangrove area of the country has been reduced from 7 lakh hectares in 1987 to 4.53 lakh hectares in 1995.
Coral reefs, mangroves and wetlands located in high altitude regions, are among the water bodies that are most sensitive to the effects of climate change!
Islands in glacial, high-altitude lakes, such as the Tsomoriri in Ladakh, were once home to several endangered bird species such as the black necked crane and the bar-headed goose. However, these islands are slowly melting away with a changing climate.
Besides climate change, there are several other reasons that plague our wetlands today. Here are some of them:
• Disposal of solid and liquid waste in wetlands
• Degradation of catchment areas.
• Pollution from industrial and agricultural discharge
• Land being taken over for development
• Tourism
• Overconsumption
• Excessive diversion of water for agriculture
• Increase in population