Sunderbans and Mangrove

  • Sunderbans is the largest single block mangrove forest in the world.

About: Sundarbans:

  • Sundarbans is a mangrove area in the delta formed by the confluence of the GangaBrahmaputra and Meghna Rivers in the Bay of Bengal.

  • It is the largest single block mangrove forest in the world.
  • The Sundarbans mangrove forest covers an area of about 10,000 sq. km, of which forests in Bangladeshextend over 6,017 sq. km and in India, they extend over 4,260 sq. km.
  • About half a million people of India and Bangladesh are dependent on the Sundarbans for their livelihood.
  • It is classified as a moist tropical forest dominated by “Sundri tree”.
    • It yields a hard wood, used for building houses and making boats, furniture and other things.

  • It acts as shelter belt to protect the people fromstorms, cyclones, tidal surges, sea water seepageand intrusion.
  • It is a UNESCO World Heritage Site.
    • A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO).

  • It is the only mangrove reserve in the world inhabited by tigers.
  • There are five reserves in the Sundarbans:
    • The Royal Bengal Tiger Reserve
    • Sundarban National Park
    • Sajnekhali wildlife sanctuary
    • Lothian Island wildlife sanctuary
    • Holiday Island wildlife sanctuary

In Focus: Mangroves

What are Mangroves?

  • Mangroves are a group of trees and shrubs, also called halophytes, that live in the saline or brackish water of the coastal intertidal zone.
  • They are referred to as ‘tidal forests’ and belong to the category of ‘tropical wetland rainforest ecosystem’.
  • Mangrove forests occupy around 2,00,000 sq. km across the world in tropical regions of 30 countries. India has a total mangrove cover of 4,482 sq. km.

  • Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand temperatures below 5o
  • It is an interface between terrestrial forests and aquatic marine ecosystems.
  • There are about 80 different species of mangrove trees. All of these trees grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate.

What is the significance of mangroves?

  • The structural complexities of mangrove vegetation create unique environments which provide ecological niches for a wide variety of organisms.
  • Mangroves serve as breeding, feeding and nursery grounds for most of the commercial fishes and crustaceans on which thousands of people depend for their livelihood.

  • Mangroves act as shock absorbers. They reduce high tides and waves and help prevent soil erosion.
  • Mangroves give protection to the coastline and minimise disasters due to cyclones and tsunami.
  • Mangrove forests are able to store three to four times more carbon than the forests which are found on land.
    • They form ecosystems which scientists refer to as “blue carbon ecosystems” as opposed to “green carbon ecosystems” which are found on the land.

  • Mangroves are an intermediate vegetation between land and sea that grow in oxygen deficient waterlogged soils which have Hydrogen Sulphide (H2S).
    • They perform important ecological functions like nutrient cycling, hydrological regime, coastal protection, fish-fauna production, etc.