Mangroves are plants that survive high salinity, tidal regimes, strong wind velocity, high temperature and muddy anaerobic soil – a combination of conditions hostile for other plants. The mangrove ecosystems constitute a symbiotic link or bridge between terrestrial and marine ecosystems. They are found in the inter-tidal zones of sheltered shore, estuaries, creeks, backwaters, lagoons, marshes and mud-flats.
Mangroves constitute a heterogeneous group of plants with similar adaptations to a particular environment. They colonize tidal shores and brackish waters in the tropics and subtropics and in doing so not only stabilize shorelines but also create new land by trapping debris, silt and mud along their interlacing roots. Mangroves plants can survive high salinity, tidal extremes, strong wind velocity, high temperature and muddy anaerobic soil.
Mangroves in India
In World’s total mangrove vegetation, India’s share stands at 3%. Currently Mangrove cover in India is 4740 km² which is 0.14 % of the country’s geographical area. Sundarbans in West Bengal accounts for almost half of the total area. As compared to 2013 there is a net increase of 112 sq km in the mangrove cover.
Top five states with maximum Mangrove cover are as follows:
• West Bengal (2106 km2)
• Gujarat (1107 km2)
• Andaman & Nicobar Island (617 km2)
• Andhra Pradesh (367 km2)
• Odisha (231 km2)
Importance of Mangroves
Mangroves are self propagating plants and if it is undisturbed, can grow quite easily in conducive soil and locations. These are the plants that grow in the inter-tidal zone along the coastline of India. They are very hardy plants that have adapted over millennia to grow in difficult conditions.
Mangrove ecosystems are rich in biodiversity and harbour a number of floral and faunal species (both terrestrial and aquatic) many of which, e.g. the tiger, gangetic dolphin, estuarine crocodile, etc. are endangered. They also act as nurseries for fin fish, shell fish, crustaceans and mollusks. Mangrove forests are regarded as the most productive ecosystems in the world on account of the large quantities of organic and inorganic nutrients released in the coastal waters by these ecosystems.
The mangroves besides providing a number of ecological services also play a major role in protecting coastal areas from erosion, tidal storms and surges (tsunamis). They help in land accretion by trapping the fine debris particles. They are also an important source of honey, tannins, wax, besides fish. Presently, these are one of the most threatened ecosystems on account of both anthropogenic factors (reclamation of land, discharge of waste etc) and natural factors like global warming.
Mangroves under threats
The satellite data shows a decrease in the mangrove area.
The natural threats to mangroves include the following:
• cyclones, typhoons and strong wave action especially in the geographically vulnerable Andaman and Nicobar Islands;
• browsing and trampling by wildlife (e.g. deer) and livestock (goats, buffaloes and cows), which are often left to graze freely, especially in areas close to human habitation;
• damage by oysters to the young leaves and plumules of Rhizophora and Ceriops plants;
• crabs, which attack young seedlings, girdle the root collars and eat the fleshy tissues of the propagules
• insect pests such as wood borers, caterpillars (which eat the mangrove foliage and damage the wood as well) and beetles;
The following are some of the human activities that have resulted in damage to mangroves
• indiscriminate tree felling and lopping, mainly for fuelwood, fodder and timber, especially in areas close to human habitation;
• indiscriminate conversion of mangroves on public lands for aquaculture (e.g. for prawn culture at Chorao, Goa), agriculture, mining (e.g. along the Mapusa estuary in Goa), human habitation and industrial purposes;
• encroachment on publicly owned mangrove forest lands, e.g. cultivation of paddy observed on government land, which involved uprooting of natural and planted seedlings;
• lack of interest of private landowners (village communities and individuals) in conserving and developing the mangroves on their lands;
• illegal large-scale collection of mangrove fruits for production of medicines, which hinders their natural regeneration;
• discharge of industrial pollutants into creeks, rivers and estuaries, which is a major problem in some regions of the world;
• obstruction and diversion of water for culvert construction.
Legal and Regulatory Approaches for Protection
At present, the mangroves are protected through a range of regulatory measures such as Coastal Regulation Zone Notification, 1991; Environment Impact Assessment (EIA) studies under the EIA Notification, 1994 for specialized industries; monitoring of compliance, with conditions imposed while according Environmental Clearance, by Regional Offices of the Ministry and State Pollution Control Boards; enforcement of emission and effluent standards by industries and other entities, and recourse to legal action against the defaulters. Mangroves located within the notified forest areas are also covered under the Indian Forest Act, 1927 and Forest (Conservation) Act, 1980.
Mangroves for the Future Initiative
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 communities, where all the ecosystems are conserved and managed sustainably and seeks to promote investment and action in ecosystem conservation for sustainable 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, Srilanka 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.