Presentation_Value of Mangroves in Coastal Protection

8/4/2019 Presentation_Value of Mangroves in Coastal Protection

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Presented By:

Akil HossainB. Sc In Environmental Science

DisciplineKhulna University

Value of Mangroves In Coastal Protection

In Bangladesh


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Mangroves are a diverse group of unrelated trees, palms, shrubs, vines

and ferns that share a common ability to live in waterlogged saline soils

subjected to regular flooding.

They are highly specialized plants that have developed unusual

adaptations to the unique environmental conditions in which they are

found.

There are around 80 species of mangroves found throughout the world.

Most commonly they occur within tropical and subtropical sheltered

coastal areas subjected to tidal influences.


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Mangroves can be divided into two distinct groups:

Exclusive mangroves

The largest group, comprising around 60 species (Saenger et al., 1983)

These mangroves are confined to intertidal areas and have not been found

to exist within any other type of vegetation community

Non-exclusive mangroves

Comprising around 20 plant species

These plants are not restricted to the typical mangrove environment and

are often found within drier, more terrestrial areas


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Mangroves are found along estuaries and marine shorelines

High tide and low tide are the common phenomena

Mangrove roots provide an oyster habitat and slow water

flow, thereby enhancing sediment deposition in this areas

Due to the high salinity and frequent tidal inundation

mangrove tree species show distinct zonation


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Adaptations to low oxygen

Limiting salt intake

Limiting water loss

Nutrient uptake

Increasing survival of offspring


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Problem Identification

The coast of Bangladesh is known as a zone of vulnerabilities as well as

opportunities. It is prone to natural disasters like cyclone, storm surge andflood. The combination of natural and man-made hazards such as erosion,

high arsenic content in ground water, water logging, earthquake, water

and soil salinity, various forms of pollution, risks from climate change,

etc, have adversely affected lives and livelihoods in the coastal zone and

slowed down the pace of social and economic developments in this

region.


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Nature of Coastal Disasters in Bangladesh

The entire coastal zone is prone to violent storm and tropical cyclones

during pre monsoon and post monsoon season. The cyclone accompanied

with torrential rain and devastating tidal surge causes havoc to lives and

property in the cyclone path, and the environment in the affected area.


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Causes of Coastal Vulnerabilities

The poverty monitoring survey of Bangladesh Bureau of Statistics (BBS) summarized

crises in following categories. Are-

a. Human factor i.e. sudden death of the main income earner, large medicalexpensesdue to illness, crop loss, social conflict etc.

b. Natural disaster like cyclone, tidal surge,water logging, erosion, salinity intrusion,

etc

c. Governance i.e. deterioration of law and order situation (dacoity, money extortion,abduction, snatching, death threat, case expenditure, occupying of govt. khas land,

natural resource base e.g. destruction of mangroves, overexploitation of natural

resources etc (PDOICZMP, 2003).


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The above figure reveals that the coastal human ecosystem is greatly

threatened by human factors and ill governance that creates imbalances in

productivity and in the distribution of goods and services.

Source: PDOICZMP, 2003


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Cyclone and Coastal Vulnerabilities

The entire coastal zone is prone to violent storm and tropical cyclones during

pre monsoon and post monsoon season. Sometimes cyclone associated with

tidal waves caused great loss of lives and property.

Source: ICZM-2003


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COASTAL PROTECTION

Mangroves as Bio-shield: Evidence from around the world

Research and experience have shown that forest ecosystems reducing the

physical exposure of natural hazards and providing people with the livelihood

resources to withstand and recover from crises

Mangrove Forests Saved Lives In Tsunami Disaster

Mangroves can absorb 70-90 percent of the energy of a normal

wave, even though reliable figures for tsunamis are not available.


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Foreshore Protection

Acting as a natural buffer to water erosion from both the land and the sea.

By creating a physical barrier

Slowing water movement from the land

Trapping sediments

Reduce erosion along estuaries and creeks

Dampen storm surge and tropical periodic cyclones


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Intertidal/Muddy Coast

This type of coast is characterized by fine-grained sedimentary deposits,

predominantly silt and clay that come from rivers; it can be classified as asoft coast. It has a broad gentle seaward slope, known as an intertidal mud

flat where mangrove forest, saltmarshes, shrubs and other trees are found.

Most erosion is generated by river damming that reduces sediment supply,

diminishes vegetation cover (usually mangroves and saltmarshes) and

exposes vegetation roots by lowering the mud flat that leads to their final

collapse.


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Scientific findings on the protective functions of coastal forests and trees

Scientific investigations on how coastal vegetation provides a measure of

shoreline protection have been show that mangrove forest and othercoastal vegetation of certain density can reduce wave height considerably

and protect the coast from erosion, as well as effectively prevent coastal

sand dune movement during strong winds. Healthy coastal forests such as

mangroves and salt marshes can serve as a coastal defense system where

they grow in equilibrium with erosion and accretion processes generated

by waves, winds and other natural actions.


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Maintaining ecological balance of the nature

By photosynthesis, supply nutrients and oxygen to animals and plants in the ecosystem.

link up the ecosystems of the land and sea.

Every hectare of mangroves can feed 12 tonnes of living things including insects, reptiles,amphibians, birds, invertebrates and various aquatic microorganisms.

Foraging and living places for wildlife

Reducing water pollution

keeping the fishery yields in coastal and offshore areas.

Acts as a sight-seeing route of eco-tours, and brings financial incentives to the community.


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Oil spills from theinternational ships, mechanize trawlers, andwater

vessels passing through the Sundarbans.

Rising sea level threatens to inundate low-lying areas and offshore

islands in the country's coastal belt

Almost all the forest area is now under shrimpfarms.

Salt Pans have been set up within the forestareas

because of lesser tide inundation andthus vegetation is getting destroyed

Encroachment and illicit removal of

timber andfuel wood is increasing

Marginallands, with about half of the

forestlands beingcultivated or occupied.


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Possible management scenarios

Public awareness and education about the mangrove forests may help protect them. It is

necessary to involve local communities in managing and protecting their mangroves.

Designated conservation areas may also save some of the forests.

Proposals/ actions need to be taken to avert future natural disasters

Action has to be taken for reforestation, restoration and development of the mangroves.

Public education campaign is to be conducted to make local communities, the tourism

industry and other sectors aware of the importance of mangroves.

Periodic mapping of Sunderbans mangrove forests has to be carried out using

the Remote Sensing and GIS technology to monitor the changes in the ecosystem.

Social forestry can be useful for eco-restoration of mangrove vegetation through creation

of employment opportunities


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Any Question?

Contact:S.M. Samkeyat Shohan

Phone Call: +8801672048125Email: [email protected]

Akil HossainPhone Call: +8801738383863Email: [email protected]

Presentation_Value of Mangroves in Coastal Protection

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