Mangroves: Key to Save the Planet

By Harsha, Nivedita Sharma and Siya Gupta

“If there are no mangroves, then the sea will have no meaning. It’s like a tree with no roots, for the mangroves are the roots of the sea!”

— Mad-Ha Ranwasii, a Thai fisherman

Mangroves are groups of trees or shrubs that grow in a distinctive environmental region between land and sea, low-lying coasts, estuaries, marshes, mudflats, tidal creeks, backwaters and lagoons. These mostly evergreen forests are found mainly in Asia, followed by Africa and South America. In India mangroves are located in Sunderbans, West-Bengal and in the Andaman and Nicobar Islands.

Distinctive features of mangroves

• The mangrove ecosystem is mainly made up of three components which work together as a system to serve the function; mangrove trees, which trap the sediment and pollutants flowing into the sea, seagrass beds, which act as further barriers to silt and mud that could strangulate the reefs and coral reefs, which protect the seagrass beds and mangroves from strong ocean waves.

• The mangroves constitute a paramount section of the littoral forest ecosystem, spreading over low lying areas of tropical and subtropical regions. They filter out saline water through their roots by making use of solar radiation. Thus, they are also called halophytes (salt tolerant) .

• Mangrove trees typically have blind roots which are referred to as pneumatophores aiding these trees to respire in anaerobic soils.

• Another unique yet remarkable feature of these forests is in regard to its method of reproduction, better known as “viviparity mode of reproduction” wherein the seeds germinate in the trees itself before falling.

• Mangrove trees also protrude distinct varieties of roots; red roots, which are found mainly along the coastlines, black roots, which have a dark bark and can take in a greater amount of oxygen and white roots, which grow at the highest elevation than the other two kinds of roots.

Importance of mangroves

• Biodiversity refuge: Mangroves provide habitat for a diverse array of terrestrial organisms, rare and endangered species. They also support a variety of marine and estuarine food webs. The mangrove ecosystem has a diverse variety of marine creatures such as fishes (barracuda, tarpon, and snook etc.), shrimps, crabs, shellfishes. The ecosystem also acts as top-tier nesting sites for birds such as kingfishers, herons, and egrets. Other than these, the wildlife extends from Bengal Tiger, mainly found in Sunderban mangroves to Crab-eating macaque monkeys, fishing cats,giant monitor lizards, olive Ridley turtles, white breasted sea eagles, tree climbing fish, proboscis monkeys, and dugongs etc.

Species found in Mangroves : Barracuda, giant monitor lizard, shrimp, Bengal Tiger, dugong, olive Ridley turtle, herons and proboscis monkey.

• Carbon sink: Mangroves have a capacity to store carbon dioxide and greenhouse gases in their woods.

• Socio-economic significance: Mostly people in rural areas are dependent on the natural environment to provide livelihood to their families. The trees are a good source of fuel and mangroves supply a rich source of fisheries.

• Bulwark against storms: Mangroves prevent excess damage due to storms because their deep roots hold the soil, thus averting erosion and providing resistance to the massive air flow.

• Clean water: Mangroves protect the saltwater and the freshwater ecosystems they bestride. Their complex root systems filter sediments, pollutants such as nitrates and phosphates that are carried by rivers and streams to the sea.

• Perform important ecological functions: These include nutrient cycling, hydrological cycle, etc.

Threats to mangrove forests

Mangrove forests face grave threats of immense destruction and extinction on the extreme end of it.

• Deforestation: Cutting down of Mangrove trees for their invaluable timber and use as fuel accounts for its destruction.

• Coastal Infrastructural Development : Rapid construction of concrete structures in the coastal areas such as resorts, nuclear power plants, port facilities etc, in the name of progressive necessities, lead to expanded levels of pollution , caused by solid waste, pesticides, thermal, biological (invasive species), brine, and oil spills etc. This causes huge amounts of damage to these vulnerable forest regions, posing an immense threat to the aquatic and terrestrial creatures as well as the growth of the mangrove trees.

• Climate Change : Rapid rise in sea level, alteration in composition of the ocean and sea water make it difficult for the mangrove trees to maintain their ability to survive in saline water conditions. Also, constant increase in acidic nature serve difficulties to the mangrove animals, (especially those with shells like oysters, snails etc.) in absorbing calcium carbonate from the water leading to growth and developmental malformations.

• Agriculture, Aquaculture and Salt-production : The mangrove ecosystem is rich in nutrients making them an ideal region for agriculture purposes, shrimp farming, creation of salt ponds for salt production. This involves clearing off large expanses of mangrove forests and destroying the wildlife . The fertilizers, pesticides or other extra nutrients and chemicals used in such processes leads to chemical imbalance in the ecosystem and eutrophication in the water bodies which lowers the oxygen levels for the marine creatures.

Conservation of mangroves

The conservation of mangrove forests came into the domain mainly after the world witnessed the havoc caused by Indian Ocean Earthquake and Tsunami in the year 2004, thus demanding the need for protection of the natural bulwark against disasters and storms. Conservation, sustainable use and restoration of mangroves is required to ensure the long-term continuity of mangrove-associated biodiversity, reduce mangrove associated anthropogenic greenhouse gas emissions and to improve the well being of people dependent on these coastal ecosystems.

Steps taken to conserve mangroves:

• The ‘Mangroves for the Future’ initiative was launched by Mr Bill Clinton, in December 2006 and in collaboration with the United Nations Development Programme (UNDP) and International Union for Conservation of Nature (IUCN) in the tsunamis prone countries. It stimulates coastal ecosystem conservation and in accordance with this initiative, India has drafted a ‘National Strategy and Action Plan’ to promote sustainable investment avenues and value ecosystem products. As a part of implementation of the Sustainable Development Goal 14 (conservation of the ocean and marine resources for sustainable development, as well as mangrove restoration), the Global Mangrove Alliance, with IUCN, The Nature Conservancy, and the World Wildlife Fund, escalated the efforts and brought more attention towards the crucial role of mangroves in coastal systems.

• Indulge local stakeholders to sustainably manage mangrove resources.

• Technology is being used to protect the mangroves, a mobile app Mangrove App - India was launched in 2017, for the first time in Asia. This app covers 24 mangroves and their associated species found in Maharashtra and 16 species found in Vikhroli. It aimed to provide information about the mangrove ecosystem, biodiversity, threats and conservation measures, etc.

Drones are being used to speed up the mangrove restoration project in order to cover a larger area, for example in Myanmar where the villagers around Irrawaddy River Delta manually planted mangrove trees.

• 26 July is celebrated as The International Day for the Conservation of the Mangrove Ecosystem to raise awareness of the importance of mangroves as a “unique, special and vulnerable ecosystem” and to promote their sustainable management, conservation and use.

Framing of new policies and programmes with efforts from national governments, NGOs, and local communities around the globe have created some positive impact to rehabilitate and manage mangroves sustainably. In Spite of awareness campaigns, slogans and policies; there is still a lot that needs to be done to make people more aware about mangroves ,threats to them and how to mitigate them sustainably.

Bibliography

“Mangrove Science Database” , ELAW : Environmental Law Alliance Worldwide. “Why Mangroves matter?”, American museum of National History. Balasubramanian Sharada (2018), Conservation of Mangrove Forests,Terra Green ,Rajasthan.