Correct Option (D)
Mangroves serve as effective natural buffers against coastal calamities primarily due to their unique and extensive root systems. Thedense, interlocking network of prop roots and pneumatophoresstabilizes the coastline, prevents soil erosion, and significantly reduces the energy of incoming waves, storm surges, and tsunamis. Theserobust root structures trap sediments and dissipate wave force, thereby protecting inland areas and human settlements from severe damage. The ability of mangrove trees to remain rooted during strong coastal events is crucial for their sustained protective function, as demonstrated during the2004Indian Ocean tsunami where areas with intact mangrove belts experienced considerably less destruction.
Incorrect Options
Option 1: While mangrove swamps do create a buffer zone between human settlements and the sea, their protective mechanism is not solely based on spatial separation or the absence of human activity within them. The primary protective function arises from their physical ability to attenuate wave energy and stabilize the coastline, rather than merely acting as an uninhabited barrier.
Option 2: Mangrove ecosystems provide various ecological services, including offering food resources and medicinal plants. However, this function is not directly related to their role as a physical safety hedge against the destructive forces of coastal calamities like tsunamis or cyclones. Their protective role is structural and ecological, not resource-based.
Option 3: The height and dense canopies of mangrove trees do not provide effective shelter against the powerful forces of a tsunami or a severe cyclone. The primary protective mechanism of mangroves against such events lies in their extensive root systems that dissipate wave energy and stabilize the coast, rather than their above-ground structure offering direct shelter.