The Mangrove EcosystemGroup No. IVVivek Iyer 201019Sanket V. Jagare 201020Yashvant Jain 201021Ishan Janabandhu 201022Nitin Kadam 201023Sandip Kadam 201024
• The word "Mangrove" is considered to be a combination of the Portuguese word "Mangue" and the English word "grove".• Mangroves are salt-tolerant plants• These are highly productive but extremely sensitive and fragile• are breeding, feeding and nursery grounds for many estuarine and marine organisms
MANGROVES IN INDIA•According to a status report of the Government of Indiapublication, the total area of the mangroves in India, wasreckoned at about 6,740 sq.km.•This covered about 7% of the world mangroves(Krishnamurthy, 1987) and 8% of the Indian coastline(Untawale, 1987).•But a recent Indian Remote Sensing Data (Nayak, 1993)showed that the total area of the mangroves decreasedto 4,474sq. km .
Functions & Benefits Of Mangrove: Ecological Functions• Natural habitat for endangered species• Deposition of mud - With mangrove forests, marine water quality maintained from silt erosion.• Nutrient enhancer - The physical properties of mangrove forests tend to slow the flow of water and precipitation occurs. - nutrients leaching from agricultural land, Benefits of mangroves are 25 fold higher than that of paddy cultivation.• Sources of germ plasm.
• Carbon sequestration - The process of change photosynthesis inorganic carbon (C02) into organic carbon in the form of vegetation material. - In most ecosystems, these materials decompose and release carbon back into the atmosphere as (C02). estimated that a loss of about 35% of the world’s mangroves has resulted in a net loss of 3.8 x 1014g C stored as mangrove biomass.• Maintaining microclimate• Prevent the development of acid sulphate soil• Maintaining processes and natural systems
Screening the solar UV‐B radiationThe mangrove foliage produces flavonoids that serve as UV‐screencompoundsReducing the green house effectsMangroves are known to remove CO2 from the atmosphere throughphotosynthesis.The mangroves are capable of accumulating and storingcarbon in the soil in large quantities.They fix greater amounts of CO2 per unit area, than what thephytoplankton do in the tropical oceans
Minimizing the fury of cyclonesMangrove forests protect all types of coastal communities from the fury ofcyclones and storms. The best example on finds is the super‐cyclone whichoccurred on the 29th October 1999 with a wind speed of 310 km hr‐1 along theOrissa coast (India) and played havoc largely in the areas devoid ofmangroves. On the contrary, practically no damage occurred in regions withluxuriant mangrove growth.
Trapping the sedimentsOne of the important functions of mangroves is trapping ofsediment, and thus acting as sinks to the suspended sediments .Themangrove trees catch sediments by their complex aerial root systemsand thus function as land expanders. Trapping and recycling of nutrientsMangrove sediments have a high capacity for absorbing andholding heavy metals thereby preventing the spread of metalpollution in coastal areas.The sediments contain 90% of Mn and Cu released andalmost 100% of the Fe, Zn, Cr, Pb, Cd in the total ecosystem.
Supporting the fishes and wildlife populationsNearly 80% of the fish catches are directly or indirectlydependent on mangrove and other coastal ecosystemsworldwidePichavaram mangroves alone nurture 30 species of prawns,30 species of crabs, 20 species of mollusks, and 200species of fishBesides fish,the mangroves support a variety of wildlife such asthe Bengal tiger, crocodiles, deer, pigs, snakes,fishing cats, insects and birds.
Biomass and Litter Production Mangroves contribute significantly to the global carbon cycle. Mangrove forest biomass may reach 700 t ha‐1 (Clough, 1992) and Twilley et al. (1992) estimate the total global mangrove biomass to be approximately 8.7 gigatons dry weight (i.e. 4.0 gigatons of carbon).Prevention of the coastal erosionThe mangrove systems minimize the action of waves and thusprevent the coast from erosion. This has been demonstrated inVietnam. In the tall mangrove forests, the rate of wave reductionper 100 m is as large as 20% (Mazda et al., l997).Another work has proved that mangroves form ‘live seawalls’, andare very cost effective as compared to the concrete sea wall andother structures for the protection of coastal erosion.
Economic Benefits• Transportation• Recreation and tourism• Education and research
Economic Benefits• The mangroves supply forestry products(firewood, charcoal, timber, honeyetc.) and fishery products(fish, prawn, crab, mollusk etc.).• mangrove twigs are used for making charcoal and firewood• One ton of mangrove firewood is equivalent to 5 tons of Indiancoal, and it burns producing high heat without generating smoke.• Used as timber for its durability.• Nypa leaves areused to thatch roofs, mats and baskets.
Facilitate apicultureFor instance, the Sundarbans provide employment to 2000people engaged in extracting 111 tons of honey annuallyand this accounts for about 90% of honey production amongthe mangroves of India (Krishnamurthy,l990).In Bangladesh, an estimated 185 tons of honey and 44.4tons of wax are harvested each year in the western part ofthe mangrove forest.
MedicinesBruguiera species (leaves) are used for reducing blood pressures andExcoecaria agallocha for the treatment of leprosy and epilepsy.Extracts from mangroves seem to have a potential forhuman, animal and plant pathogens and for the treatment of incurableviral diseases like AIDS
Threats to the mangrove ecosystem Natural Anthropogenic• Climatic changes • Deterioration• Cyclones • Diseases• Physical processes. • Pollution • Grazing • Agriculture, aquaculture • Human encroachment (including reclamation)
•Approximately 35% of mangrove area was lost during thelast several decades of the twentieth century• which encompass about half of the area of mangroves.[• The United Nations Environment Program also estimatedshrimp farming causes a quarter of the destruction ofmangrove forests.• Likewise, the 2010 update of the World Mangrove Atlas(WMA) indicated a fifth of the worlds mangroveecosystems have been lost since 1980.
Most of the challenges to mangrove forests observed in Goaand the Middle Andamans are also relevant to other partsof India. These include both natural hazards anddestructive human activities. However,the gravity of the problems varies from area to area.
Natural hazards•Cyclones, typhoons and strong wave action•Browsing and trampling by wildlife•Infestation by barnacles which attach to youngseedlings, interfering with respiration andphotosynthesis and delaying seedling growth•Damage by oysters to the young leaves
•Crabs, which attack young seedlings, girdle the rootcollars•Gastropods that eat young leaves and flowers ofmangroves, a big problem in the Middle Andamans;•Insect pests such as wood borers, caterpillars (whicheat the mangrove foliage and damage the wood aswell)•Weeds such as Acrostichum aureum and Acanthusspecies, which often occupy deforested mangroveareas and restrict the regrowth of economicmangrove tree species;
Solutions :• Tall nursery-grown seedlings should be used for planting,• Mixed plantations
Problems caused by humans•Indiscriminate tree felling and lopping, mainly forfuel wood, fodder and timber, especially in areas closeto human habitation.•indiscriminate conversion of mangroves on publiclands for aquaculture human habitation andindustrial purposes.•lack of interest of private landowners (villagecommunities and individuals) in conserving anddeveloping the mangroves on their lands.
•Illegal large-scale collection of mangrove fruits, which hinders their natural regeneration•The traditional use of dragnets in fishing.•Discharge of industrial pollutants into creeks, rivers.
Problems caused by humans, can be tracedto the following root causes•the poverty of the local inhabitants, which forces them todepend on mangroves for their fuelwood, timber and fodderrequirements even if collection is illegal;•increasing population, resulting in more pressure onmangroves;•lack of education and awareness regarding the importanceof mangroves, and ignorance of rules and regulationsregarding conservation of mangroves;
•improper planning of development activities such asaquaculture, agriculture, construction for humanhabitation, mining and industrial-ization;•short supply of fuelwood, timber and fodder at affordableprices;•absence of a systematic survey of the area and theownership of the land under mangroves, facilitatingencroachment on this land;
The government of Goa has already bannedfelling of 15 species of mangroves for a period often years under the Goa, Daman and DiuPreservation of Trees Act, 1984.
Mangrove conservation and development effortsundertaken by the Government of India, theGovernment of Goa and the Andaman and NicobarIslands Administration have so far been successful inreducing the degree of problems, but there is scopefor further improvement.
Directions of mangrove protection policy.a) Mainstream the sustainable management of mangroves into the forestrysector regulatory regime, ensuring that they continue to provide livelihoods tolocal communities.b) Disseminate available techniques for regeneration of coral reefs, and supportactivities based on application of such techniques.c) Explicitly consider sea-level rise and vulnerability of coastal areas to climatechange and geological events, in coastal management plans, as well asinfrastructure planning and construction norms.d) Adopt a comprehensive approach to Integrated Coastal Management byaddressing linkages between coastal areas, wetlands, and river systems, inrelevant policies, regulation, and programs.e) Develop a strategy for strengthening regulation, and addressing impacts, ofship-breaking activities on humanhealth, and coastal and near marine resources.
It has been cited that mangroves can help buffer againstTsunami, cyclones, and other storms.One village in Tamil Nadu was protected from tsunamidestruction-the villagers in Naluvedapathy planted 80,244 saplingsto get into the Guinness Book of World Records.- This created a kilometre-wide belt of trees of variousvarieties. When the tsunami struck, much of the landaround the village was flooded, but the village itselfsuffered minimal damage.
ReforestationIn some areas, mangrove reforestation is alsounderway. Red mangroves are the most commonchoice for cultivation, used particularly in marineaquariumsMangroves also appear in home aquariums, and asornamental plants, such as in Japan.In Senegal, Haïdar El Ali has started the Océanium deDakar project, which (amongst others) focuses onreforesting several areas with mangroves.
Programmes to raise peoples awareness of the importance ofmangroves, e.g. through films, exhibitions, newspapers,magazines, posters, stickers, brochures, banners, seminars,nature camps, birdwatching, study tours in the mangroveforests, establishment of mangrove parks in the mangroveareas close to towns, and the celebration of MangroveConservation Day, with essay competitions, debates anddrawing competitions
•incentives for sustainable management of mangroveson private and village community land;•enforcement of environmental protection laws;•research on problems related to pests and diseasesand on appropriate management of the mangroveecosystem;•restoration and rehabilitation of degraded mangroveareas.