MANGROVE ECOSYSTEM



Published on 23 Feb 2025

India is home to about 3 percent of the total mangrove cover in South Asia, with the Sundarbans in West Bengal and Bhitarkanika mangroves in Odisha being the richest in diversity.

About Mangrove ecosystem

  • Location: Mangroves are found in tropical and subtropical areas, thriving between 25°N and 25°S latitude.

  • Salty Survivors: Mangroves boast unique adaptations for their harsh environment:

    • Stilt Roots: Provide support in muddy soil.

    • Pneumatophores: Aerial roots that help them breathe underwater.

    • Salt Excretion Glands: Release excess salt through leaves.

    • Salt Excluding Roots: Filter out salt from absorbed water.

    • Viviparous Seeds: Germinate on the tree for a survival advantage.

  • Global Presence:

    • Species: 24-29 families, around 70 species worldwide.

    • Distribution: 147,359 km² globally (2020 data) 

      • Asia-Pacific: 51%

      • Americas: 29%

      • Africa: 20%

    • Leaders in Mangroves: Indonesia (20%), Brazil, Australia, Mexico, Nigeria (nearly half the world's total)

  • India and Mangroves:

    • Increase in Mangrove Cover: According to the India State of Forest report, the country's mangrove cover has increased by a significant 930 sq km since 1987.

    • 2021 Forest Survey Report: As per the report, India's total mangrove cover stands at 4,992 sq km.

Significance of Mangrove ecosystem

  • Disaster Shields: Mangroves are nature's coastal guardians. Their dense roots:

    • Reduce wave impact, protecting shorelines from erosion.

    • Stabilize sediments, mitigating coastal flooding.

    • A recent study estimates India's mangroves provide annual flood protection worth over $7.8 billion. During Cyclone Amphan (2020), Sundarbans mangroves acted as a bio-shield, protecting millions. They are vital for "building back better" after natural disasters.

  • Ecosystem Powerhouses: Mangroves are teeming with life:

    • Critical habitats for diverse plants, animals, and fish, including commercially important species.

    • The Sundarbans, home to the endangered Bengal tiger and Ganges dolphin, showcase this rich biodiversity.

  • Natural Filters: Mangroves act as nature's water purifiers by:

    • Trapping sediments, pollutants, and excess nutrients.

    • Improving water quality for coastal communities and marine ecosystems.

  • Climate Champions: Mangroves are an aid in carbon sequestration as:

    • They absorb vast amounts of CO2, storing it as "blue carbon" in their biomass and sediments.

    • Globally, they sequester half the annual Carbon dioxide emissions (estimated) from human activities.

  • Livelihood Lifelines: Mangroves support coastal communities:

    • Provide income and food for fisherfolk, with 900,000 Indian households relying on them.

    • Nurture estuaries and support nature-based economies.

    • Roughly 60% of India's coastal fish depend on these ecosystems.

  • Tourism and Recreation: Mangroves offer sustainable tourism opportunities as Eco-tourism, birding, kayaking, and other activities can generate income for local communities.

Threats faced by Mangrove Ecosystem

  • Rapid Loss: Mangroves are disappearing globally at an alarming rate, with losses exceeding 1-2% per year and a staggering 35% in the last two decades.

  • Declining Diversity: Over 16% of global mangrove species are threatened with extinction, including two Indian species – Sonneratia griffithii (critically endangered) and Heritiera fomes (endangered). This threat extends to associated fauna, with nearly 15% of all mangrove-dependent creatures facing a similar fate.

  • Rising Sea Levels: Rising sea levels, exceeding 3mm annually, pose a major threat through erosion, habitat loss, and increased salinity in inland areas.

  • Oil Spills: Oil spills suffocate mangroves, disrupting oxygen intake and leading to widespread death.

  • Plastic Pollution: Mangroves are particularly vulnerable to plastic pollution carried by rivers, with Southeast Asia being the most affected region globally.

  • Lack of Protection: Mangroves outside protected areas are vulnerable due to the absence of legal safeguards.

  • Reduced Freshwater Flow: Dams and reduced river flows threaten mangroves, especially in low-rainfall areas like the Cauvery estuary.

  • Urbanization: Infrastructure development and housing projects destroy mangroves through clearing and drainage for urban expansion.

  • Other Threats: Industrial waste, fertilizer runoff, and deforestation contribute significantly to mangrove loss.

Initiatives to conserve Mangrove ecosystem

  • Government Initiatives:

    • MISHTI (Mangrove Initiative for Shoreline Habitats & Tangible Incomes): This program aims to conserve and manage over 540 sq km of mangroves across 13 states.

    • National Coastal Mission Programme: This scheme focuses on developing annual action plans for mangrove and coral reef conservation in coastal states and territories.

    • Sustainable Aquaculture in Mangrove Ecosystem (SAIME): This initiative promotes sustainable aquaculture practices that coexist with mangrove conservation and restoration.

  • State-Level Action:

    • Maharashtra: A dedicated unit for mangrove and coastal biodiversity conservation combines scientific knowledge with capacity building for local communities.

    • West Bengal: The Mangrove Cell fosters collaboration between government, NGOs, and academics to address conservation challenges.

  • Global Collaboration for a Brighter Future:

    • Mangrove Alliance for Climate (MAC): This international initiative, with India as a member, aims to educate the world about the role mangroves play in combating climate change.

    • Save Our Mangroves Now: This joint effort works to halt the global decline of mangroves.

Way Forward

  • Local Community Engagement: Successful conservation hinges on involving local communities. Examples from Gujarat and Odisha showcase the power of collaboration through incentives and stewardship programs.

  • Policy and Planning: A comprehensive national plan is crucial, considering local needs and incorporating standardized metrics to track progress and adapt strategies.

  • Combating Threats: Measures to curb pollution, prevent illegal logging, and promote mangrove planting are essential.

  • Monitoring and Sustainable Practices: Continuous monitoring using data and promoting sustainable practices among those who depend on mangroves are key.

Raising Awareness: Understanding the impact of mangrove degradation on local biodiversity is crucial for developing effective conservation strategies.

Tags:
Geography

Keywords:
MANGROVE ECOSYSTEM Significance of Mangrove ecosystem Threats faced by Mangrove Ecosystem Initiatives to conserve Mangrove ecosystem

Syllabus:
General Studies Paper 1

Topics:
Physical Geography