Mangled mangroves

All that may remain of the pristine mangrove forests of coastal Tamil Nadu is degraded forest tracts and plundered biodiversity

 
By N Ramesh
Published: Wednesday 31 January 1996

THE mangrove forest ecosystem along the Tamil Nadu coast faces threat due to rampant human intervention, prawn farming and the changed dynamics of the flow in the Cauvery river system. The ministry of environment and forests status report, 1987, states that India has a total mangrove forest area of 6,740 sq km. Of this, the east coast has 70 per cent of the nation's mangrove area. Tamil Nadu reportedly has 150 sq km of mangrove forests. These are predominant in the alluvial delta of the Cauvery near Muthupettai in Nagai-Quaid-De-Milleth district and Pitchavaram. coastal area in south Arcot district.

Muthupettai has a total mangrove forest area of 12,425 ha, of which, 6,003 ha are reserved forests. These are being cleared for prawn farming. Mangrove trees are felled in large numbers and used as fuelwood for domestic purposes, hotels and for brick kilns. Under such pressures, the Muthupettai Environment Conservation Society was formed to preserve the mangrove forests. Teastall owners, brick kiln operators and women were appealed not to use the fuelwood from mangrove trees.

Muthupettai has been home to 56 plant species of which the important ones are Avicennia marina, A officinalis, Excoecaria aqallocha, Saueda maritima and Acanthus illicifolius. Now, soil erosion in Cauvery's catchment area and reduced waterflow is gravely affecting the Muthupettai mangrove ecosystem.

Abdul Rahman, head, department of zoology, AVVM Sri Pushpam College, Poondi, says, "Heavy sedimentation is taking place in the mouth of Koraiyar river. Low-lying areas are elevated. New mangroves come up in the resulting microdeltas. Since access to the sea is affected, fisherfolk congregate in lagoons, thereby affecting the nursery ground of fish and prawns. To facilitate river flow into the sea and seawater flow during high tide, necessary dredging should be undertaken. Prawn farms are using saline water on large scale in the lagoon area. Also, while pumping the water from the lagoon, small organisms were destroyed in the sieve attached to the pipes. Taking saline water from lagoons for prawn farms should there fore be banned. If this two-pronged action is not taken, within 10 years we will have the forest area devoid of water."

In Pitchavararn - constituted of 51 small islets - the pressure is mainly due to tourism and cattle grazing, which is said to arrest sapling growth. Eighty-six plant-', vrawn and more than 58 fish species were identified in the region. The forest area is spread over 1,100 ha. But according to the satellite imagery obtained in 1993, the actual forest area has dwindled to 147 ha.

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