Q.Discuss the causes of depletion of mangroves and explain their importance in maintaining coastal ecology. (Answer in 150 words)

Body Analysis

Causes of Mangrove Depletion

• Sea Level Rise and Erosion: Climate change-induced sea level rise floods mangrove habitats, while continuous coastal erosion degrades their shoreline foundations.

• Altered River Inflow: Mangroves thrive in brackish water where rivers meet the sea. Upstream dams reduce freshwater and sediment inflow, disrupting the delicate salinity balance.

• Invasive Species: The introduction of non-native flora and fauna disrupts the local ecological balance, threatening native mangrove species.

• Land Clearing: Large-scale clearing for agriculture, human settlements, and commercial shrimp farming accounts for a 2% to 8% annual loss of mangroves.

• Over-harvesting: Local communities overexploit mangroves for firewood, construction timber, charcoal, and animal fodder.

• Coral Reef Degradation: Healthy coral reefs act as natural barriers against strong waves. Their destruction allows intense wave action to wash away the fine sediments required for mangrove growth.

• Pollution: Agricultural runoff (fertilizers, pesticides) and untreated industrial/domestic sewage heavily pollute mangrove estuaries.

• Climate Extremes: Extreme weather events, including prolonged droughts and high sea-surface temperatures, stress mangrove survival.

Importance of Mangroves in Coastal Ecology

• Edge Effect: Mangroves exhibit high biodiversity, supporting a rich variety of species at the transition zone between terrestrial and marine environments.

• High Productivity: They are among the most productive terrestrial ecosystems; the Sundarbans, for example, supports about 30 distinct mangrove species.

• Ecological Niches: They serve as vital breeding, feeding, and nursery grounds for marine life and commercial fisheries.

• Natural Water Filters: Mangroves trap sediments and filter pollutants from river runoff before it reaches the open ocean, protecting nearby coral reefs.

• Natural Shock Absorbers: Their dense root systems reduce the impact of high tides, storm surges, cyclones, and tsunamis, while protecting shorelines from erosion.