Previous Year Question
The 2004 tsunami made people realise that mangroves can serve as a reliable safety hedge against coastal calamities. How do mangroves function as a safety hedge?
The mangrove swamps separate the human settlements from the sea by a wide zone in which people neither live nor venture out
The mangroves provide both food and medicines which people are in need of after any natural disaster
The mangroves trees are tall with dense canopies and serve as an excellent shelter during a cyclone or tsunami
The mangroves trees do not get uprooted by storms and tides because of their extensive roots
Correct Answer: D
Detailed Solution
Mangroves are salt-tolerant forests found in the intertidal areas of tropical and subtropical coasts, estuaries and deltas.
They possess specialized roots such as prop roots, stilt roots, pneumatophores and knee roots.
Their extensive root system keeps the trees firmly anchored in soft and water-saturated coastal sediments.
Consequently, mangrove trees are not easily uprooted by storms, sea waves and tides.
The dense network of roots, trunks and branches creates friction in water flow and reduces the speed and energy of waves.
Mangroves reduce the impact of storm surges and tsunami waves and also control coastal erosion.
Their roots trap sediments and help stabilize the shoreline.
Option (a) is not correct because mangroves do not provide protection merely by creating an uninhabited zone between settlements and the sea.
Option (b) describes an ecological utility of mangroves, but it is not the process through which they provide physical protection from coastal disasters.
Option (c) is not correct because taking shelter under tall trees during a cyclone or tsunami is not safe.
The protection provided by mangroves depends upon the width of the belt, vegetation density, species, coastal topography and intensity of the disaster.
Therefore, mangroves are natural safety barriers, but they are not a complete substitute for safe evacuation and engineered coastal-protection measures.
During the 2004 Indian Ocean tsunami, relatively less damage was observed in some settlements located behind intact mangrove belts.
Mangroves also provide breeding grounds for fish and crustaceans and support biodiversity conservation and blue-carbon storage.
Major mangrove regions of India include the Sundarbans, Bhitarkanika, Godavari–Krishna Delta, Pichavaram, Muthupet and the Andaman and Nicobar Islands.