Veli mangroves under threat

By M. Harish Govind

THIRUVANANTHAPURAM, SEPT. 3 The population of mangroves along the Veli Lake coast is on the decline due to human encroachment, illegal sand-mining and clandestine felling.

Botanists have expressed concern over the fact that most of the true mangrove species such as `Rhizophora apiculata' and 1Rhizophora mucronata' around the lake have disappeared over the years, to be replaced by what are called mangrove associates such as "kaitha" (pandanus).

The Veli Lake is the smallest Lake in the State, with a length of 1.25 km and a width of 0.44 km. It is situated five km northwest of the city and a permanent canal, Parvathiputhanar, connects it to the Kadhinamkulam backwaters in the north.

The lake receives inputs of fresh water from the Aakkulam Lake and other small streams while effluents are discharged into it by Travancore Titanium Products (TTP) and English Indian Clays, apart from domestic sewage.

According to Dr. A. Mohandas, senior scientist with the Tropical Botanical Garden Research Institute (TBGRI), the death-knell of the mangrove vegetation around the lake was rung with the laying of the railway track and road along the mangrove-prone areas around it.

The road laying necessitated the building of granite walls, for which the mangroves were chopped down and the lake fringes replanted with acacia and rain-trees.

Part of the land abutting the Veli Lake is under the control of the Tourism Department and part of it under that of the Indian Space Research Organisation (ISRO). The area controlled by the ISRO is out of bounds for the public and the mangrove vegetation here has benefited from the isolation.

However, the mangroves falling in the area under the Tourism Department are vulnerable to human interference as well as the pollution caused by oil spills from the pleasure boats that ply along the lake every day, according to Dr. Mohandas.

The Veli Boat Club runs about 10 speed-boat services on an average daily and the number increases to about 40 during festival seasons such as Onam.

A tourism official, when contacted, however, said the motorised boats stuck to the centre of the lake as the banks are heavily silted. Denying that oil spills occurred from the boats, he said illegal sand-mining and tree-felling posed the biggest threat to the mangrove vegetation here.

The depletion in the mangrove population is indicated by two surveys conducted in the area, the first in 1962 and the second in 1986. A marked difference was noticed in the distribution and abundance of the individual species in the two surveys.

Out of the 12 species which were common to both the surveys, five were classified as "abundant" in the 1962 study. By the time the 1986 study was conducted, only two of these species were abundant.

Mangroves, which constitute an eco-specific vegetation, are exclusive to tropical climates. Needing partially saline water to survive, they act as a bulwark separating the land and sea and help preserve the coast from sea erosion.

It is pointed out that Kerala had abundant mangrove vegetation as the State had large stretches of backwaters linked to the sea, which ensured brackishness from tidal action.

The mangroves, which cling to the coast, absorb the shock of waves by dint of their spring-like action, it is pointed out. The shallows between their stilt-roots form ideal spawning grounds for a variety of marine life, including shrimp.

Meanwhile, the suitability of Veli as a tourist destination itself is being questioned in view of the pollution from English Indian Clays as well as TTP. The proximity of the ISRO premises, a high-security zone, is also pointed out as a negative factor.

Botanists point out that the majority of mangroves are in the wetland zone and in order to prevent the further destruction of this invaluable vegetation, the Government should bring wetland zones also under the proposed Coastal Zone Management Authority.

Send this article to Friends by E-Mail

Section  : Southern States
Previous : Voice of moderation from the land of booming guns
Next     : Call for joint effort to check caste evil