Discuss the causes of depletion of mangroves and explain their importance in maintaining coastal ecology.

Why mangrove belts shrink

• Shrimp and fish aquaculture cleared wide mangrove belts in the Godavari–Krishna deltas, parts of Odisha, and South-East Asian coasts for export ponds.
• Ports, special economic zones, roads, and city landfill have cut mangroves around Mumbai, Kochi, and other fast harbours.
• Agriculture, salt pans, and fuelwood cutting nibble fringes in Gujarat and Tamil Nadu, while upstream dams trap sediment that mangroves need to keep up with the sea.
• Oil spills, plastic, and industrial waste poison roots; cyclones and sea-level rise then uproot weakened stands, as seen after storms in the Sundarbans and the Andaman coasts.
• Weak enforcement of Coastal Regulation Zone rules and unclear tenure let conversion continue even where maps still show a green belt.

Importance for coastal ecology

• Stilt roots trap mud, cut wave energy, and reduce storm surge, which is why villages behind the Sundarbans and Bhitarkanika suffer less erosion than open mudflats.
• The forest is a nursery for fish, crab, and prawn that later feed the open sea and artisanal catch.
• Litter and roots store blue carbon and keep water quality by filtering nutrients before they reach seagrass and coral.
• Tigers, saltwater crocodiles, olive ridley nesting beaches nearby, and countless waders use mangrove edges as a linked habitat, not as a separate park.
• Pichavaram, Coringa, and Mumbai’s remaining patches still show that a living mangrove is cheaper coastal defence than a concrete wall.

What the two parts imply

• Depletion is mostly a land-use choice; ecology pays in fisheries, storms, and carbon when that choice is extraction.