Importance of Mangroves

a. Buffer Zone between the land and sea.b.Protect the land from erosion. c. Play an invaluable role as nature's shield

against cyclones, ecological disasters and as protector of shorelines.

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

e. Harbour a variety of lifeforms like invertebrates, fish, amphibians, reptiles, birds and even mammals like tigers.

f. Good source of timber, fuel and fodder.g.Main source of income generation for shoreline

communities like fisherfolk.h.Save the marine diversity, which is fast

diminishing.i. Purify the water by absorbing impurities and

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

j. Potential source for recreation and tourism. 

Why should we protect mangroves?...........

Mangroves, admittedly, are not only important but crucial for the coastal areas. Since estuarine areas are highly populated areas, the slightest ecological imbalance will take a heavy toll. They play a vital role in stabilizing these areas. No engineering and technological solutions can be sought for stabilizing

these areas. Even if we negate all benefits of mangroves as forests, their value as "protector of shore-line" is enough to convince us for conserving them.

Mangroves are buffers between the land and the sea. Coastlines throughout the world are facing serious problems of coastal erosion and threat of rising sea levels due to global warming have increased the threats by several folds. To control such assault of the sea on land the nature has provided what is called as Mangroves, a tropical littoral ecosystem which is more dynamic than the sea itself.

Mangroves not only help in preventing soil erosion

but also act as a catalyst in reclaiming land from seas. This is a very unique phenomenon, since there is a general tendency of water to engulf land.

Mangrove forests and estuaries are the breeding and nursery grounds for a number of marine organisms including the commercially important shrimp, crab and fish species. Hence, loss of mangroves not only affects us indirectly but there are direct economic repercussions through loss of fishing industry.

         

Mangrove trees are also used for house building, furniture, transmission as well as telephone poles and certain household items. When these activities are managed appropriately it is possible to derive timber products from mangrove forests without significant environmental degradation, and while maintaining their value as a nursery and a source of food for commercial capture fisheries.

In many coastal areas including Gulf of Kutch, mangroves are a substitute for fodder. Thus mangroves reduce pressures from the scarce pasturelands.

Tannin is extracted from the bark of some mangrove species like Rhizophora mucronata, Bruguiera

gymnorrhiza and Ceriops tagal. Indian mangrove trees have 35% tannin in their bark, which is higher compared to other countries. Extracts from mangrove bark are used by Indian fishermen to dye their fishing net and enhance its durability.

Mangrove trees have been the source of firewood in India since ancient time. Because of the high specific gravity of rhizophoraceous wood, the species of Rhizophora, Kandelia, Ceriops and Bruguiera are preferred for firewood. Heritiera agallocha is used for boat building, while Avicennia spp. and Rhizophora spp. are used for brick-burning. Bruguiera spp. are used to make poles. Honey collection from the mangrove forest is a promising business in India. It has been estimated that Sundarbans mangrove alone produce 111 tons of honey annually. Honey collected from Cynometra ramiflora and Aegialitis rotundifolia has a good market value and is in demand. 

Avicennia spp., Phoenix paludosa and Sonneratia caseolaris are used for human consumption and as cattle feed. Nypa fruticans is tapped for an alcoholic drink. Leaves of Nypa palm are used for thatching of roofs, Suaeda and Acrostichum leaves are used as green vegetable.

Above all, Mangroves are now looked after by scientists as saviors in the today's scenario of global warming. We all know that most of the coastal areas throughout the world are going to be affected by sea level rise due to global warming. The effects of which

are already visible. Therefore, when most of the coastal areas will be flooded, mangroves can possibly provide a gene bank for cultivating salt tolerant species of crops which could be our future resource

Where do Mangroves occur

The richest mangrove communities occur in tropical and sub-tropical areas, i.e., between the 30°N and 30°S latitudes where the water temperature is greater than 24ºC in the warmest month, where the annual rainfall exceeds 1250mm and mountain ranges greater than 700m high are found close to the coast. Mangroves are found practically in almost all the continents, excepting Europe, the Arctic and Antarctic. Luxuriant patches of mangroves are found on all the other continents but the best mangroves are found in Asia, especially in India and Bangladesh - the Sunderbans are the largest mangrove forest in the world both in size as well as biodiversity

The total area of mangroves in India is about 6,740 sq. km, which is about 7% of the world's total area of mangroves. Of the total mangroves 80% are present along the east coast, mostly forming the Sunderbans, Bhitarkanika and the Andaman & Nicobar mangroves. The Gangetic Sunderbans is about 4,000 sq. km whereas Andaman & Nicobar is about 700 sq km. Besides, large rivers like Mahanadi, Krishna, Cauveri, Godavari also harbour major mangroves in their estuarine regions.

The remaining 20% mangroves are scattered on the west coast from Kutch to Kerala. The reason for such a restricted mangrove cover is the peculiar coastal structure and the nature of estuaries formed by the relatively small and non-perennial rivers except Narmada and Tapi.

How do they establish?

Under the right conditions like the formation of a mud-flat, growth of mangroves is initiated. Stabilization of mud-flats is a preliminary process in the establishment of mangroves. Pioneer plant species initiate this process. The roots of these plants help in binding the soil and also help the establishment of micro-organisms which further help in stabilizing the area. Stabilization starts from the land side and gradually shifts towards the sea. The pioneer plants are species like Porterasia coarctata and some members of the Cyprus family. These are slowly replaced by other mangrove plants and then these mangroves gradually spread towards the sea.

Once mangroves grow, the submerged banks are fully stabilized. Then the plants slowly reach a stage which is called the climax vegetation. A climax vegetation of mangroves is represented by the complete circle of life where there are different species of plants, animals (both terrestrial and aquatic) and micro-organisms forming an ecosystem called the tropical salt marsh or the mangrove ecosystem. In case the sediments are not stabilized, submerged banks are washed out. Thousands of

deltas are formed and washed out every year before they can be stabilized. In the Gangetic delta this situation is quite common.

MORE ABOUT MANGROVES

Mangrove ecosystem is a peculiar habitat found at the interface between land and sea.

The term "mangrove" is being applied to the specific ecosystem of the intertidal world in the tropics and subtropics and the plant community of this ecosystem is termed as "mangrove vegetation".

Many people think that mangroves are a few dwarf weedy plants along the shoreline but mangroves are much more than that. It is a whole ecosystem acting as a buffer between land and sea. Mangroves are

extensions of tropical and sub-tropical forests into the sea.

Mangroves are found extensively in the estuarine

regions where mud-flats are wide and gently sloping. Besides estuaries, they also inhabit the intertidal regions of shallow bays and creeks where the environment is conducive for the growth of mangroves. Mangroves are flood buffers. They also help to stabilize climate by moderating temperature, humidity, wind and even waves. They are specially adapted to withstand salinity, wave action, and can grow in poor soils. They actually protect the land from the impact of the sea.

Growing in the intertidal areas and estuary mouths between land and sea, mangroves provide critical habitat for a diverse marine and terrestrial flora and fauna. Healthy mangrove forests are key to healthy marine ecology.

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.

Major threats

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

• Industrial and domestic pollution

8. Values

Mangroves are the mainteners of near shore marine habitats and simultaneously provide varieties of commercial and economic values to a variety of organism in different trophic levels. Besides the commercial and economic values, mangroves also play a major role in maintaining different types of environmental problems. The economic and commercial values as well as environmental values are shown in the following table:

Economic and Commercial values

Firewood and CharcoalAdhesive

Timber for house and ship building

Fish food and fish float

Fishes Crocodile skinShrimps and prawns PerfumeCrabs, shelfish amd crustaceans

Soft wood industries

Birds OilsTannin Alcohol used as

transport fuelMammals RayonPly wood FibrePaper pulp AmphibianFodder CondimentsHoney and wax Sweet meatMedicine Cigarette wrappersEnvironmental values

Protection from wind, storm, cyclone and act as a cost free

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.

Major threats

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

• Industrial and domestic pollution

self repairing static security guardShore line stabilizationDecrease coastal erosionProtect inland flora and fauna from the effect of sea level riseEssential habitat for spawning and nursery bed of marine fishesSewage and industrial pollutant resistantEssential habitat for Royal Bengal TigerEssential habitat for scarlet eye bees and other endangered migratory birdsEssential habitat for estuarine crocodiles, dugongs, dolphinEssential habitat for Olive Ridley TurtlesEssential habitat for sea ottersEco-tourism Education and Scientific studies

PROBLEMS

Indiscriminate Tree felling and Lopping. Indiscriminate Conversion of Land, Creeks and Channels. Industrial Pollutants. Global Threats Regarding the Rise of Temperature due to Green House Drift and Rise of Sea Level. Encroachments. Ownership of Land. Traditional Method of Fishing. Cattle Pressure. Wood Borers & Pests. Infestation by Barnacles, Oysters, Crabs and Gastropods. Grass Cutting. Mortality of Mangrove Trees.

STRATEGIES

Preservation

(Absolute Protection for Biodiversity)

Conservation

(Human use of the Protected Areas under Biosphere Reserve, National Park & Santuaries)

Use of Mangrove Areas for Various Economic Purposes

(Acquaculture, Mariculture, Fishing, Nagivaion, Eco-Tourism, Water Sports, Salt Production, Sea weed Culture etc.)

Large Scale Plantation in Degraded Mangrove Area

Mangroves in Mumbai...........

History

Mumbai Historical records indicate that there were several islands around Mumbai during 1670. However, the Britishers, who were ruling the country identified the importance of these islands for commercial purpose. They deforested the fringing mangroves and reclaimed these islands into one continuous landmass, which later came to be known as "Greater Bombay". Since then the developmental and bsequently population pressure rapidly increased and being the coastal area, it took the toll of mangrove land. During the process of deforestation and reclamation, a few mangrove patches are still left in the heart of the city, which proves that today's megacity had a luxuriant past of mangrove forests (fig). Major mangroves are seen today in Mumbai along the Vasai Creek, Thane

Creek, Manori and Malad, Mahim - Bandra, Versova, Siwari, Mumbra - Diva and few more places.

Importance of Mangroves for Mumbai

Mangroves represent the spirit of Mumbai – they are plucky survivors. But each day, millions of citizens in Mumbai pass these hardy plants imagining they are little more than dirty, muddy weeds growing pointlessly along the shoreline. How little people understand just how important mangroves are to th`e quality of life of the citizens of Mumbai.

By trapping silt, mangroves maintain the integrity of Mumbai’s shoreline. This is a vital service to the city of Mumbai as it is very prone to erosion, having been built on reclaimed land that is battered by the sea on all three sides. The recent rains in Mumbai and the disaster that followed demonstrated the consequence of tampering with the ecology of fragile ecosystems like mangroves. Had Mumbai’s Mithi river and Mahim creek mangroves not been

destroyed by builders, fewer people would have died and the property damage would have been dramatically less.

The Koli community in Mumbai worships mangroves because they know that these are breeding and nursery grounds for the marine organisms on which their sustenance depends.

Mangrove community of Mumbai

In the early nineties, perhaps over 37 sq. km. of mangroves existed in Mumbai, largely in the Thane creek, Mahim, Versova, Gorai and Ghodbunder, with sporadic patches in places such as Bandra, Malabar Hill and Colaba. Mumbai has probably lost 40 per cent of all its mangroves in the past decade or so, largely because of reclamation for housing, slums, sewage treatment and garbage dumps. Fortunately, thanks to the Godrej family, we still have excellent mangrove forests in Vikhroli (Link). Around 20 out of the 35 species of true mangroves found in India have been identified along the Maharashtra coast and 15 species of these are found in Mumbai.

Because of the high salinity of the soil, something like 60 per cent of Mumbai mangroves comprise Avicennia marina. Nor surprisingly this species also tolerates pollution including heavy metals such as lead, mercury and chromium, all found in significant concentrations in the Mithi river.

Mangrove destruction in Mumbai

Rapid developments like housing, industrialization, pollution and increasing population of Mumbai has resulted into degradation of mangroves. There are two important creeks, Vasai Creek towards north and

Thane Creek toward south where luxuriant mangrove patches are still left. Otherwise the State Govt. agencies have failed to protect this important, productive mangrove ecosystem from building mafias.v

The worst affected area in Mumbai is the entire western front excepting Carter Road where the mangroves have grown and have also registered an increase in height in the last 10 years. This has been possible due to the participation of citizen’s forums fighting individually.

In India, a legal protection is afforded to this ecosystem by way of legislation in the form of Coastal Regulation Zone Notification. Recently Mumbai High Court has ordered freeze on destruction of mangrove forests in Maharashtra and has banned construction within 50 metres of them. The court has also directed to notify mangrove areas as protected forests. Thus, there is already a mechanism provided for management of this ecosystem. Unfortunately, however many a times the legal provisions are not being enforced to curb the illegal activities.

In such a situation, protection of the mangrove ecosystem is possible only through the participation of the local community and by building up pressure groups for ensuring management of this ecosystem and strict implementation of the legal provisions by the Government. Thereby, integrity of habitats critical for spawning, juveniles and feeding and for biodiversity, apart from ecological sustainability and

community-sustainability could be maintained.

In the past few years there has been an increase in the awareness of the people in Mumbai. Residents associations are coming together to spread this

awareness. They realize that the rapid destruction of mangroves along the coast of Mumbai will have far-reaching effects on the city. The NGOs in Mumbai are making efforts to highlight the issues like land reclamation, coastal regulation zone notification and illegal destruction of the mangrove areas through the interventions of the local state government and a local bodies.