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  • 8/2/2019 Mangroves 3


    Environment Management

    Project on

    Mangroves around the world

    Importance and Why to protect

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    MangrovesAn Introduction

    A mangrove is a tree, shrub, palm or ground fern,

    generally exceeding one half metre in height, that

    normally grows above mean sea level in the intertidal

    zone of marine coastal environments and estuarinemargins.

    A mangrove is also the tidal habitat comprising such

    trees and shrubs

    The term "mangrove" comes to English from Spanish

    word mangueand english word grow

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    Though the trees themselves are few in species, the

    ecosystem that these trees create provides a home for

    a great variety of other organisms.

    Protection from strong winds & waves

    Soil stabilization & erosion protection

    Nutrient retention and water quality improvement

    through filtration of sediments and pollutants Protection of associated marine ecosystems

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    Evolution of Mangroves

    Evolved around 114 million years ago Indo-Malaysian area is considered as cradle of

    evolution of mangrove system

    Mangroves of West Africa and Americas contain

    fewer but similar colinizing species.

    Asia, India, and East Africa contains much full range

    of mangove species

    At present, Indo-Pacific region is also known asluxuriant Mangroves

    Sunderbans of India and Bangladesh forms the single

    largest block of mangroves of the world

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    Where do Mangroves occur?

    The richest mangrove communities occur in tropicaland sub-tropical areas

    The best mangroves are found in Asia especially in

    India and Bangladesh Sunderbans are the largest forest mangrove in the

    world both in size as well as biodiversity

    Total area of Mangroves is about 6,740 sq. km7%

    of the worlds total area of mangroves 80% of the mangroves are present in the east coast

    Remaining 20% are scattered on the west coast fromKutch to Kerela

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    Importance of Mangroves

    Buffer between land and sea

    Play an invaluable role as nature's shield againstcyclones, ecological disasters and as protector ofshorelines

    Harbour a variety of lifeforms like invertebrates, fish,

    amphibians, reptiles, birds and even mammals liketigers

    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 byabsorbing pollutants in the air.

    Potential source for recreation and tourism

    Saviors in todays scenario of global warming

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    Mangroves vegetation

    The mangrove flora of the world is represented by

    about 65 species.

    The Indian mangroves are represented byapproximately 59 species (inclusive of some

    mangrove associates) from 29 families.

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    Few commonly found plant species in

    Mangrove ecosystem are:

    Rhizophora apiculata (Red Mangrove): It grows well in sheltered areasrather than open seas exposed to the wave action.

    Rhizophora mucronata (Red Mangrove): It is often notice as a front

    mangrove plant where the shore is well protected. It has a high growth rate

    and is economically important. The species is quite similar to R. apetala

    Bruguiera gymnorhiza (Broad leaf orange mangrove): Roots arecharacteristically thick, rope-like and filled with air. They are called "cable


    Parviflora (Small leaf orange mangrove): Essentially a back mangrove

    species. It is a useful tree for commercial extraction of tannin. The leaves

    are supposed to be used for treating high blood pressure. Sonneratia alba (Mangrove Apple): It prefers non swampy intertidal

    zones and prefers open areas with some wave action. It has thick, pointed

    and long pneumatophores. The apple like fruits are edible and used in


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    Ceriops tagal (spur mangrove): A widely distributed species with a high

    tolerance for salinity.

    Avicennia marina: Avicennia spp have the highest salt tolerance of

    mangrove trees. One of the dominant species found throughout thecoastline.

    Avicennia officinalis: Of the three dominant species of Avicennia this is

    the tallest. The wood is used as timber and fuel. Extraction of tannin is still

    done at some places. Leaves useful as fodder for cattle.

    Acanthus ilicifolius (Shore purslane): One may notice this attractiveplant in the back mangrove zones. Its shrubby nature and spiny leaves

    make it an outstanding species.The blue flowers are also a source of nectar

    for honey bees. The flowers and leaves are used for decoration in Kerala.

    Aegiceras corniculatum (River mangrove): A densely flowering shrub.

    Salt tolerance of this species is comparatively low and grows only in theareas where there is good mixing of freshwater at least for a few months. It

    seeds profusely between January and March and fruits are curved and very

    finely pointed. The nectar produces fine quality honey.

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    Phoenix padulosa (Sea Date): This palm species is also called as sea date

    and is a relative of the common date. In Sunderbans, this species forms a

    major zone along the upper reaches of the delta. It is used as a fuel and its

    trunk is used for constructing traditional hutment. It grows naturally onlyon the East Coast.

    Nypa fruticans (Golpatta): This is a characteristic palm species and

    resembles a shrunken coconut tree. It prefers well consolidated but moist

    tidal zones with a low to medium level of salinity preferably with

    freshwater mixing. Heritiera fomes (Sundari): This plant is locally called as sundari in W.

    Bengal. The name Sunderban perhaps has been derived from the abundance

    of this species in the Gangetic delta. It produces timber of excellent quality

    which is said to be more expensive than teak.

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    Coastal Regulation Zone (CRZ) Rules 2011.


    Coastal regulation zone is the boundary from the high tide line up to 500min the landward side area between the low tide line. In the case of rivers,

    creeks and backwaters, the distance from the high tide level shall apply to

    both sides and this distance shall not be less than 100m or the width of the

    creek, river or backwater whichever less is.

    There are four categories of CRZs.CategoryI (CRZ I)

    Areas which are ecologically sensitive and important such as national

    parks, areas close to breeding and spawning grounds to fish and other

    marine life. Historically important and heritage areas, area rich in genetic

    diversity, areas likely to be inundated due to rise in sea level consequentupon global warming and such other areas as notified by government from

    time to time.

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    Mangroves around the world

    The countries with the largest area of mangroves are:

    1) Indonesia

    2) Brazil

    3) Australia

    4) Nigeria

    5) Mexico

    Estimates of mangrove diversity indicate that there are 16-24

    families and 54-75 species worldwide. The greatest mangrove

    species diversity exists in SE Asia.

    Only 12 mangrove species are found in the Americas, with 4

    of these occurring along portions of the SE USA (Florida)

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    Sundarban Forest The Sundarbans is the largest mangrove forest in the world

    300 species of trees and herbs

    425 species of wildlife including the Royal Bengal Tiger exist.

    It lies in south-east of Calcutta .

    It covers some 10,000 of mangrove forest and water (of which some

    40% is in India and the rest in Bangladesh)

    It is a part of the worlds largest delta (80,000 sq. km.) formed fromsediments deposited by three great rivers, the Ganges, Brahmaputra and


    The three sanctuaries are intersected by a complex network of tidal


    mud flats, small islands of salt tolerant mangrove forests.

    The area is flooded with brackish water during high tides which mix with

    freshwater from inland rivers.

    The Sundarbans has experienced balanced growth of flora and fauna in

    association with the fresh water of the Ganges and the salty sea water of

    theBay of Bengal.

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    The Sundarbans mangrove area of India and Bangladesh when

    taken together forms one of the worlds largest single patches.

    Tidal waves are a regular phenomenon and may be up to 7.5m

    high About half of the Sundarbans is under water and the rest of the


    Rainfall is heavy and humidity high (80% on average) due to

    proximity of the Bay of Bengal. The entire mangrove forest extends over an area of 4,262 of which 2,320 is forest and the rest is water and

    it is called Sundarban, locally known as sundari.

    It is classified moist tropical seral forest, comprising beachforest and tidal forests.

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    This mangrove forest generally bears the salt-tolerant

    forest ecosy