KARNATAKA

Destruction of wetlands bodes ill for the future

Udupi May 9. The massive destruction of wetlands in Udupi and Dakshina Kannada districts is causing concern as it could lead to long-term economic and environmental damage.

According to the Convention on Wetlands of International Importance held at Ramsar in Iran in 1971, and to which India is a signatory, wetlands are defined as "areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres".

The Ramsar Convention also provides that wetlands "may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands." The Ramsar Convention extended not only to fresh water sources such as rivers and lakes, but also coastal and shallow marine ecosystems, including coral reefs, artificial water bodies, and underground water resources.

There are more than 24 Ramsar sites in India -- major wetlands, which should be conserved from the biodiversity point of view. Some of these include the Sunderbans in West Bengal and the Chilka Lake in Orissa.

The World Wetlands Day is celebrated on February 2 every year. The Ramsar Convention was initially meant for conservation of wetland birds. Later, it was realised that wetland ecosystems were cradles of biodiversity upon which, besides birds, countless species of plants and animals depended for survival. Of the 20,000 species of fish in the world, more than 40 per cent live in fresh water. Wetlands are renowned for high levels of endemic species, especially fish and invertebrates. Many varieties of prawn, mollusc, and insect are found only in the wetlands. The theme of the World Wetlands Day this year is "Wetlands: Water, life and culture".

Wetlands hold water either permanently or temporarily so that it percolates into the ground, thus making it essential for water conservation. They are intimately associated with the economic and cultural aspects of human beings. For instance, many people subsist on snail-catching during monsoon when they cannot go out for fishing.

There are about 540 large and small ponds, and a 141-km.-long coastline with many important estuaries lined on it in Udupi and Dakshina Kannada districts. The Gangolli estuary in Udupi District is one of the 17 important estuaries in India identified by the Man and Biosphere (MAB) Programme of the UNESCO. Similarly, there are other estuaries such as the ones at Udyavar, Mulki, and Someshwara. These estuaries are cradles of marine animals such as prawn and fish. Marine prawns breed in estuaries and then go back to salt water. A threat to an estuary is a threat to these animals. Estuaries in Udupi and Dakshina Kannada districts attract migratory birds such as Terek Sandpiper, Curlew Sandpiper, Redshank, Greenshank, Dunlin, Sanderling, Ruddy Turnstone, Temmenik's Stint, Little Stint, Black tailed Godwit, Little Sand Plover, Little Ringed Plover, Brownheaded Gull, and Blackheaded Gull, among others.

N.A. Madhyastha, Principal, Poornaprajna College, Udupi, and an authority on wetlands, says that many rare birds have been recorded at the Gangolli estuary, but due to the intensive prawn culture in the region now, birds such as Green Sandpiper, Whimbrel, and Avocet have stopped coming here.

Another essential aspect of the estuarine ecosystems is the mangroves, which are economically important as they are the sources of firewood and medicine. The estuaries also help stabilise the sea shores and river banks.

As regards inland water in these districts, nearly 75 per cent of ponds are dying due to siltation and overgrowth of weeds. Weeds cover the Anekere Lake in Karkala. Ecologically, it has reached a stage wherein in a couple of years, it will be land for most part of the year. One of the immediate consequences of this will be scarcity of water around the lake. Since this lake is very shallow it will not hold water, thereby checking percolation leading to depletion of groundwater. If immediate measures are not taken, scarcity of water may hit the lake. This also holds true for the other ponds in both the districts.

About four decades ago, people used to construct bunds across streams in September to check the flow of water into sea. This water conserved till December facilitated the recharging of groundwater. This is no longer being followed leading to scarcity of water in the districts.

Urbanisation has also led to depletion of lakes and ponds. About a decade ago, there were many small ponds in Udupi and Dakshina Kannada districts, which held water till the end of December, giving enough time for percolation and re-charging the groundwater. Dr. Madhyastha says that the filling of these ponds with municipal garbage or waste material to construct buildings has destroyed the water recharging machinery resulting in water scarcity in the districts. With the forest cover getting depleted, silt accumulating in tanks, and rivers going dry during summer, the role of wetlands cannot be exaggerated.

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