(Environment & Ecology) Aquatic Biomes - Mangroves Importance, Threats, Future & Mangroves in India



Mangrove forests or Mangas grow at tropical and subtropical latitudes near the equator where the sea surface temperatures never fall below 16° C. Mangroves lie in about two-thirds of the coastlines in tropical areas of the world.

There are about 80 Species of mangrove trees, all of which grow in hypoxic (oxygen poor) soils where slow-moving waters allow fine sediments to accumulate). Many mangrove forests can be recognized by their dense tangle of prop roots that make the trees appear to be standing on stilts above the water. This tangle of roots helps to slow the movement of tidal waters, causing even more sediments to settle out of the water and build up the muddy bottom. Mangrove forests stabilize the coastline , reducing erosion from storm surges, currents, waves and tides.

Just likes the high and low areas of salt marshes where specific types of grasses are found, Mangroves have distinct zones characterized by the species of mangrove tree that grows there. Where  a species of mangrove tree exists depends on its tolerance for tidal flooding, soil salinity, and the availability of nutrients, Generally, there are three dominant species of mangrove trees. The red mangrove (Rhizophora Mangle) colonizes the seaward side of the Mangrove, so it receives the greatest amount of tidal flooding. Further inland and at a slightly higher elevation, black mangroves (Avicennia Germinans) grow. The  zone in which black mangrove trees are found is only shallowly flooded during high tides. White mangrove (Laguncularia Racemosa) and buttonwood trees (Conocarpus Erectus). A non-mangrove species, face inland and dominate the highest parts of the Mangrove. The zone where white mangrove and buttonwood trees grow is almost never flooded by tidal waters.

A  unique mix of marine and terrestrial species lives in Mangrove ecosystem. The still, sheltered waters among the mangrove  roots provide protective breeding, feeding, and nursery areas for snapper, tarpon, oysters, crabs, shrimp and other species, important to commercial and recreational fisheries. Herons, brown pelican, and spoonbills all make their nests in the upper branches of mangrove trees. Mangrove trees have become specialized to survive in the extreme conditions of estuaries. Two key adaptations they have are the ability to survive in waterlogged and anoxic (no oxygen) soil, and the ability to tolerate brackish waters.

Some mangroves remove salt from brackish estuarine waters through ultra-filtration in their roots. Other species have special glands on their leaves that actively secrete salt, a process that leaves visible salt crystals on the upper surface of the leaves.

All mangrove species have laterally spreading roots with attached vertical anchor roots. These roots are very shallow. Because the soil in shallow areas of mangrove forests is typically flooded during high tides, many species of mangrove trees have aerial roots, called pneumatophores that take up oxygen from the air for the roots. Some species also have prop roots or stilt roots extending from the trunk or other roots that help them withstand the destructive action of tides, waves, and storm surges.

Many mangrove trees also have unique method of reproduction. Instead of forming seeds that fail to the soil below and begin growing, mangrove seeds begin growing while still attached to the parent plant. These seedlings, called propagules, even grow roots. After a period of growth, these seedlings drop to the water below and float  upright until they reach water that is shallow enough for their roots to take hold in the mud.

Importance of Mangroves

  • Buffer Zone between the land and sea.

  • Stabilize the coastline, reducing erosion from storm surges, currents, waves, and tides.

  • Play and invaluable role as nature’s shield against cyclones, ecological disasters and as protector of shorelines.

  • Breeding and nursery grounds for a variety of marine animals.

  • Harbour a variety of life forms like invertebrates. Fish, amphibians, reptiles, birds and even mammals like tigers.

  • Good source of income generation for shoreline communities like fisherfolk.

  • Save the marine diversity, which is fast diminishing.

  • Purify the water by absorbing impurities and harmful heavy  metals and help us to breathe a clean air by absorbing pollutants in the air.

  • Potential source for recreation and tourism.

  • The intricate  root system of mangroves also makes these forests attractive to fish and other organisms seeking food and shelter from predators.

Threats to Mangrove Ecosystem

Large demographic pressure is exerting tremendous stress on the coastal environment. The main culprit in the destruction of mangroves is man. To achieve harmful supremacy over nature, human have destroyed this magnificent ecosystem almost irreparably. Land reclamations and industrial effluents are the major causes of mangroves degradation. Systematic dumping of all kinds of waste and debris in the mangrove areas destroys them. Land reclamations and industrial effluents are the major causes of mangroves degradation. This waste/debris creates a barrier preventing the sea water from entering the mangroves and eventually kills the mangroves. In many instances, this is done intentionally to reclaim land for construction activity. There is an urgent need to stop this systematic degradation of mangroves.

To summarise, major threats are:

  • Land reclamations for construction activity, aquaculture, agriculture, tourism

  • Industrial and domestic pollution

  • Port development

  • Dumping of all kinds of waste and debris

  • Deforestation for fuel wood

  • Over harvesting of marine resources

Mangroves in India

Mangrove in India is world famous for its rich variety of flora and fauna and also for its huge area. The Sundarbans comprise the principal portion of Mangrove in India. The Sundarban mangroves occupy a huge area followed by the Andaman-Nicobar islands and Gulf of Kachchh in Gujarat. Compared to the Sunderbans, the rest of the mangroves ecosystem are comparatively smaller. The Mangrove in India is home to a large number of over 1600 plant and 3700 animal species. Mangrove in India is found in tropical and sub-tropical tidal areas, and in the areas that have a high degree of salinity.

Mangrove in India includes numerous species that helps maintaining the balance or ecosystem in India. There are several places where mangrove in India is found including the Godavari Krishna and Sundarbans. Mangrove occurs on islands in the Indian Ocean, Arabian sea Bay of  Bengal, in India and the Sunderbans is considered as the largest mangrove forest the world. Sunderbans is located in the Ganges delta in the state of West Bengal, India apart from that, major mangals can also be found in the Andaman and Nicobar islands are the Gulf of kutch in Gujarat. Some of the other significant mangals found in India, include the Bhitarkanika Mangroves and Godavari-Krishna mangroves. The second largest mangrove  forest in the world, the world, the Pichavaram Mangrove Forest is situated near Chidambaram in South India and it is home to a large variety of birds. The birds include the local resident, migratory resident and the pure migratory birds and the forest is separated from the Bay of Bengal by a lovely beach. It is also one of those rare mangrove forests. Which has actually increased by 90% between the years of 1986 and 2002.

Sunderban Mangrove delta complex :-  Sundarbans, a cluster of 102 miracle islands, form the largest mangrove delta complex on the globe in the estuarine phase of the Ganges and Brahmaputra Rivers, constitute a unique Biosphere Reserve in the coastal Bay of Bengal and host landmark ancient heritage of the mythological and historical events bestowed with wide bio-diversity of mangrove flora and fauna, magnificent scenic beauty  and natural resources of immense scientific, anthropological and archaeological interests. This region is one of the world’s nost remotely challenged geographical  regions with a population density of more than 1100 person per sq. km.

“Sundarban” literally means “beautiful jungle or forest” in Bengali language. The name Sundarbans may also have been derived from the Sundari trees that are omnipresent in Sundarbans. Other possible explanations can be a derivation from “Samudra” Ban” (sea Forest) or “Chandra-bandhe” (name of a primitive tribe). However, the generally accepted view is attributed to Sundari trees.

Mangroves for the Future (MFF)

Mangroves for the Future (MFF) is a unique multi-country, multi sectoral, Partner-led initiative which builds on the long history of coastal management interventions and lessons learned during the course of post-tsunami reconstruction and rehabilitation. The initiative is founded on a vision for a more healthy, prosperous and secures future for all Indian Ocean Coastal development. MFF is being coordinated by International Union for Conservation of Nature, IUCN covering, initially, six Tsunami affected countries namely India, Indonesia, Maldives, Seychelles, Sri Lanka and Thailand. India has agreed to participate in the IUCN covering, initially, Six Tsunami affected countries namely India, Indonesia, Maldives, Seychelles, Sri Lanka and Thailand. India has agreed to participate in the IUCN-MFF Initiative.

Mangroves for the Future have two objectives:

  • To strengthen the environmental sustainability of coastal development.

  • To promote the investment of funds and effort in coastal ecosystem management for sustainable development.

The initiative seeks to effect demonstrable changes and results across four key areas of influence : regional cooperation, national programme support, private sector engagement and community action using a strategy of generating Knowledge, empowering institutions and people to use that knowledge and, thereby promoting good governance in coastal areas.