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The Causes of Deterioration of Sundarban Mangrove Forest Ecosystem of Bangladesh: Conservation and Sustainable Management Issues


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The Sundarban forest, located in the southwest of Bangladesh, is one of the largest continuous blocks of mangrove forests in the world. This mangrove forest ecosystem in Bangladesh is now in captious position. Negative natural and anthropogenic impacts and overexploitation of natural resources have caused severe damage to the ecosystem. Growing human population with few alternative livelihood opportunities poses a serious threat to the mangrove forest. The rapidly expanding shrimp farming industry is a significant threat to the mangrove forests of Bangladesh. Due to illegal cutting, encroachment of forest areas and illegal poaching of wildlife, the mangrove forest is losing biodiversity in an alarming rate. This forest ecosystem also has become vulnerable to pollution, which may have changed the ecosystem's biogeochemistry. Further threats arise from global climate change, especially sea level rise. This study seeks to identify the root causes of deterioration of the Sundarban mangrove forest in Bangladesh. It also recommends the application of sustainable management strategies covering needs for an advanced silvicultural system, improvement of scientific research as well as conservation measures.
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AACL Bioflux, 2010, Volume 2, Issue 3. 77
Aquaculture, Aquarium, Conservation & Legislation
International Journal of the Bioflux Society
The causes of deterioration of Sundarban
mangrove forest ecosystem of Bangladesh:
conservation and sustainable management issues
1Mohammed M. Rahman, 2M. Motiur Rahman, and 3Kazi S. Islam
1Graduate School of Intregrated Arts and Science, Faculty of Agriculture, Kochi
University, Japan; 2Silvacom Ltd., Edmonton, Canada; 3The School of Oceanography and
Environmental Science, Xiamen University, Xiamen, P.R. China.
Corresponding author: M. M. Rahman,
Abstract. The Sundarban forest, located in the southwest of Bangladesh, is one of the largest continuous
blocks of mangrove forests in the world. This mangrove forest ecosystem in Bangladesh is now in captious
position. Negative natural and anthropogenic impacts and overexploitation of natural resources have caused
severe damage to the ecosystem. Growing human population with few alternative livelihood opportunities
poses a serious threat to the mangrove forest. The rapidly expanding shrimp farming industry is a
significant threat to the mangrove forests of Bangladesh. Due to illegal cutting, encroachment of forest
areas and illegal poaching of wildlife, the mangrove forest is losing biodiversity in an alarming rate. This
forest ecosystem also has become vulnerable to pollution, which may have changed the ecosystem's
biogeochemistry. Further threats arise from global climate change, especially sea level rise. This study
seeks to identify the root causes of deterioration of the Sundarban mangrove forest in Bangladesh. It also
recommends the application of sustainable management strategies covering needs for an advanced
silvicultural system, improvement of scientific research as well as conservation measures.
Key Words: Sundarban, Mangroves, Bangladesh, deterioration, sustainable management. (In Bangla)
Rezumat. Pădurea Sundarban, aşezată în sud-vestul Bangladesh-ului, este unul dintre cele mai mari
blocuri permanente de pădure de mangrove din lume. Acest ecosistem este acum într-o situaţie delicată.
Efectele negative naturale şi antropice şi exploatarea în exc es a resurselor naturale au cauzat daune
severe la nivelul ecosistemului. Creşterea populaţiei umane cu posibilităţi alternative reduse de trai
constituie o ameninţare gravă la adresa padurilor de mangrove. Creşterea rapidă a industriei
producătoare de creveţi este o ameninţare semnificativă pentru aceste păduri. Datorită tăierilor ilegale,
violării zonelor forestiere şi a braconajului de animale sălbatice, padurea de mangrove pierde
biodiversitatea într-un ritm alarmant. De asemenea, acest ecosistem a devenit vulnerabil la poluare, care
ar putea schimba biogeochimia ecosistemului. Alte ameninţări sunt generate de schimbările climatice
globale, mai ales creşterea nivelului mării. Acest studiu urmăreşte să identifice cauzele de deteriorare a
pădurilor de mangrove Sundarban în Bangladesh. Se recomandă, de asemenea, punerea în aplicare a
strategiilor de management durabile care acopere nevoile unui sistem silvic avansat, îmbunătăţirea
cercetării ştiinţifice, precum şi a măsurilor de conservare.
Cuvinte cheie: Sundarban, mangrove, Bangladesh, deteriorare, management durabil.
AACL Bioflux, 2010, Volume 2, Issue 3. 78
Introduction. The total geographic area of Bangladesh is approximately 14.40 million
hectares (ha) of which 13.46 million ha are land surface and 0.94 million ha are rivers
and other inland water bodies (GoB 1993; Islam 2005). According to a recent estimate,
the country has only 18% (2.58 million ha) of forest coverage. On the basis of
geographical location, climate, topography and management principles, the forests can
broadly be classified into: hill forests, mangrove forests, plain land sal forests,
unclassified state forests, and homestead forests (Motiur 2006). The Sundarban is the
largest mangrove ecosystem in the world. This ecosystem contains numerous tributaries
of the Ganges delta, strewn along the Bay of Bengal’s coastal belt in southwest
The anthropogenic impact on mangroves has increased rapidly over the past
decades. That is why so many countries are showing losses of 50-80% or more (73% for
Bangladesh; WRI 1996) compared to the mangrove forest cover during the 1960s.
Mangrove wetlands are regularly felled to make way for aquaculture, development of
coastal cities, and beaches. According to studies carried out at different times by the
Forest Department, British ODA and UNDP/FAO sponsored Forest Resource Management
Plan, the mean volume ha-1 of the Heritiera fomes (Aiton, 1789) (local name Sundari)
was 34.5 m3 in 1959. The volume was reduced to 19.9 m3 in 1983 and 17.8 m3 in 1996.
In the case of Excoecaria agallocha (Linnaeus 1758) (local name Gewa) the mean volume
ha-1 was 8.7 m3 in 1959, which was reduced to 4.6 m3 in 1983 and 2.1 m3 in 1996. The
rapid decrease is blamed on overexploitation, legally and illegally clear cutting and
pollution. Mangroves are under pressured by many threats such as human
encroachment (including reclamation), shrimp farming and other forms of aquaculture,
grazing, agriculture, diseases and natural disasters e.g. storms, floods, cyclones, coastal
erosion and natural changes in hydrology, sea level rise and inadequate regeneration.
There were also impacts of degradation due to the development of two main seaports at
Khulna and Chittagong, which handle most of Bangladesh’s imports and exports,
respectively. This study seeks to identify the root causes of deterioration of the
Sundarban mangrove forest and to propose adequate recommendations for sustainable
management and conservation of this unique UNESCO World Heritage site for both
people and nature.
Study Area. Sundarban forest, located in the southwest of Bangladesh, is one of the
largest continuous blocks of mangrove forests in the World, lieing between 21º30´ N and
22º30´ N and 89º00´ E and 89º55´ E (see Figure 1). Total geographic area is
approximately 6017 km2 which represents 23% of total forest area of Bangladesh (Anon
2000). This wetland consists of about 200 islands separated by about 400 interconnected
tidal rivers, creeks and canals (Banglapedia 2010).
Biodiversity of Sundarban Mangrove Forest. Sundarban has extremely rich diversity
of aquatic and terrestrial flora and fauna. Mangroves are associated with flowering plants,
palms, ferns, bryophytes, fungi, algae, lichens and bacteria. Chaffey et al (1995)
recorded about 334 plant species, including 35 legumes, 29 grasses, 19 sedges, 18
euphorbia and 50 true mangrove plant species. It is noted that mangrove forests are
habitats to about 500 species of wild vascular plants (FAO 2004). A mentionable amount
of economically important plants are found in this forest. Fauna have been poorly studied
in comparison to flora (Macintosh & Ashton 2002), but according to FAO estimates,
Sundarban mangrove forest is home to ca. 840 species of wild animals, including. 419
Royal Bengal tigers (MoEF 2004). Within the forest habitats, there are ca. 50 species of
mammals, ca. 320 species of inland and migratory birds, ca. 50 species of reptiles, eight
species of amphibians, ca. 400 species of fish, as well as insects. Mangroves are also the
nursery and/or breeding grounds for several commercially important species of aquatic
fauna (Saenger 2002). Among the invertebrates some molluscs and crustaceans
constitute important fisheries resources. About 20 species of shrimps, 8 species of
lobsters, 7 species of crabs, several species of gastropods, and 6 species of pelecypods
have been reported from the Sundarbans (Pasha & Siddiqui 2003). Among the shrimps
Penaeus monodon (Fabricius, 1798) and Metapenaeus monoceros (Fabricius, 1798) and
AACL Bioflux, 2010, Volume 2, Issue 3. 79
the mud crab Scylla serrata (Forsskal, 1775) are commercially important. Over 120
species of fish are said to be commonly caught by commercial fishermen (Seidensticker &
Hai 1983). The shallow swamps around the mangroves sustain an ideal breeding and
nurshing ground for fishes, juvenile shrimps and endangered species such as olive ridley
turtle (Lepidochelys olivacea (Eschscholtz, 1829)), gangetic dolphin (Platanista gangetica
(Roxburgh, 1801)), hawks bill turtle (Eretmochelys imbricate (Linnaeus, 1766)) and King
Crab Carcinoscorpius rotundicauda (Latreille, 1802). A large number of economically
important plants are found in the forest. Mangrove forests are not only abundant in plant
species but also crucial for local populations (Table 1).
Figure 1. Map showing the distribution of mangrove forest of Sundarban in Bangladesh.
Table 1
Economically important plants of the Sundarban
and their uses (after Siddiqi 1998)
Family Scientific Name Type of Plant Main Uses
Avicenniaceae Avicennia officinalis Tree Fuel wood, Anchor
Combretaceae Lumnitzera racemosa Small tree Fuel wood, Posts
Euphorbiaceae Excoecaria agallocha Tree Matchsticks and Raw
material for newsprint
Leguminosae Cynometra ramiflora Small tree Fuel wood, Charcoal
Malvaceae Xylocarpus mekongensis
Xylocarpus granatum Tree Furniture, Bridges, house
Nypa fruticans Recumbent Palm
with underground
Thatching for houses Palmae
Phoenix paludosa Thorny palm Post and rafters for huts
Bruguiera spp. Tree Furniture, Bridge and
house construction
Ceriops decandra Shrub or small tree Fuel wood, House posts,
Sonneratiaceae Sonneratia apetala Tree Packing boxes, Paneling
Sterculiaceae Heritiera fomes Tree House construction Hard
AACL Bioflux, 2010, Volume 2, Issue 3. 80
The Causes of Deterioration of Sundarban Mangrove Forest. Sundarban mangrove
forest is the most threatened habitats in the world (Rahman 2009). The increased
population with few alternative livelihood opportunities poses a serious threat to the
Sundarban as it is the main cause of mangrove destruction (Ong 1995; FAO 2003; Ali et
al 2006). Excessive exploitation and negligence of restocking are the main cause of
overall depletion of growing stocks of Sundarban forest (Ali et al 2006). The growing
stock of the Sunderban forest has depleted from 20.3 million m3 in 1959 to 10.9 million
m3 in 1996 (FAO 2000).
Mangrove forests in Bangladesh are deteriorating due to over-exploitation,
deforestation, land reclamation and pollution. Large areas of mangroves have been
cleared for fish and shrimp farming. Agricultural practices and industrial development,
urbanization, over-logging in coastal areas as well as unregulated discharge of liquid and
solid wastes are the most serious threats. Overall, the causes of deterioration of
Sundarban mangrove forest ecosystem could be classified into:
1. anthropogenic
2. natural
3. other (or miscellaneous)
1. Anthropogenic Causes
Over-exploitation and Illegal Forest Cutting. Over-exploitation of forests to meet the
growing requirement of the people is one of the main problems facing the Sundarban.
Encroachment and illicit removal of timber and firewood from the forests and the absence
of sustainable management practices are the major forest conservation problems in the
area. The main reason of illicit removal of timber are: wide gap between the demand and
supply of wood and almost permanent unemployment in rural areas, which results in
compelling dependence on gathering of wood from the forests for subsistence; existence
of organized groups of mongers who professionally indulge in illegally cutting and
removing of valuable trees. Mangroves are partially in the district of Khulna, which is also
the site of a government paper mill. The factory relies on nearby legal timber supplies,
but with the Sundarban so close, illegal loggers have been making forays into the inner
regions of the forest. Sundarban have been exploited for timber, fuel wood, bark tannin,
animal fodder, native medicines and food (fish, shellfish, honey and wild animals) for
centuries, but population pressure has greatly increased the rate of exploitation, leading
to serious degradation.Due to illegal cutting, continuous encroachment of forest areas
and illegal poaching of wildlife, the mangrove forest is quickly disappearing and as a
result biodiversity of the area is reducing in an alarming rate.
Shrimp Farming. The rapidly expanding shrimp farming industry possesses the crucial
cause for deteriorating the mangrove forests in Bangladesh (see Figure 2). Moreover,
recently, mangroves have been used for fish, shrimp and especially giant tiger prawn
Penaeus monodon (Fabricius, 1798) farming (Chowdhury & Ahmed 1994). The Chokoria
Sundarban has been completely destroyed in recent years because of shrimp farming
(Iftekhar & Islam 2004). There are 14 different fishing methods and gears used by the
fisherman inside the Sundarbans. These may be clustered into three major groups based
on target species and fishing gear. Shrimp fry fishing in particular is considered to be
very destructive. Post-larvae (PLs) are being collected at unsustainable levels to supply
shrimp grow-outfarms and massive clearance of large areas of mangroves is taking place
to construct shrimp ponds, contributing to degradation and loss of mangrove habitats.
Shrimp farms are primarily located in the south-western part of the country, in the
districts of Khulna (19%), Satkhira (19%), and Bagerhat (29%); farms in the south-
eastern part of the country exist primarily in thedistrict of Cox’s Bazar (31%). Shrimp
aquaculture in Cox’s Bazar annually uses 620 tons of urea, while introducing 15 tons of
waste to the water on a daily basis. Large amounts of natural and synthetic chemicals,
including dichlorides, malachite green, debris root, and tea seed cake are used in coastal
aquaculture worldwide for the control of pests and diseases (GESAMP 1991). Saclauso
(1989) listed 14 chemicals and drugs commonly used in brackish water aquaculture
ponds of Bangladesh.
AACL Bioflux, 2010, Volume 2, Issue 3. 81
Figure 2. Production time-series of farmed shrimp over the last two decades in
Bangladesh (after DOF 2001).
Pollution. Industrial development, agriculture and aquaculture near the river basins,
population increase along with attempts to improve or modernize the living standards in
coastal areas, has led to the production of huge amounts of garbage, waste water,
pollutants and other effluents being discharged to the mangrove wetland (Rahman et al
2009). The Sundarban mangrove forest ecosystem also has become vulnerable to
pollution such as oil spillage, heavy metals, agrochemicals–especially pesticides and
nutrient enrichment–which may have changed the mangrove ecosystem's
biogeochemistry (Rahman et al 2009). Oil pollution is a serious threat in the Sundarban
and could be especially damaging to aquatic fauna and seabirds. Sources of oil pollution
are potentially the port at Mongla at the north edge of the mangroves and the numerous
large shipping vessels passing through the Sundarban each day via the north-east
shipping route (ESCAP 1988; Scott 1989). Mongla sea port is situated three Km away
from the Sundarban forest. Approximately 400 ships, numerous mechanized river crafts
and fishing boats are handled annually at this port. These vessels release waste oil,
spillage, balast water and bilge washings. Crude oil and its derivatives are the most
dangerous pollutants which enter to the mangrove forest due to oil transportation
(Iftekher 2004). Increased traffic also increases noise and air pollution and the potential
hazard of oil spills and industry effluents (newsprint mill, match factory, hardboard, boat
building, furniture making) can easily degrademangrove ecology (Islam 2001). The oil
attached on the leaf surface can block up stomata and affect photosynthesis, respiration,
and water metabolism of mangrove plants (Peng 2000). Table 2 shows the response of
mangroves to oil pollution. Reported Organic pesticides and high concentration level of
heavy metals such as Zn, Cd, Cr, Pb, Cu have been reported in mangrove sediment
(Rahman et al 2009).
AACL Bioflux, 2010, Volume 2, Issue 3. 82
Table 2
The response of mangroves to oil pollution
(after Iftekher 2004; Rahman et al 2009)
Foliage and canopy
Reduced leaf number, leaf area index, twisting
or curling
Altered leaf maturation sequences
Change in leafing and shading pattern
Abscission of immature leaves
Spotty chlorosis or necrosis
Reproductive structures
Absent or grossly excessive flowering
Change in timing of flowering or fruit set
Developmental failure of fruit
Abortion of flowers or immature fruit
Deformed seed or propagules
Failure to change floating orientation
Trunks and branches
Top dying and lowering of canopy height
Mortality in outer most sun branches
Cessation of terminal shoot growth
Fissuring and creaking of bark
Expanded or more numerous lenticels
Shortened internodes distances
Appearance of trunk sprouts
Failure to establish primary root system
Failure to initiate primary branching
Failure to geotropic orientation in propegules
Abnormal growth forms in young seedlings
Chlorosis or necrosis of propagules
Aerial root structures
Proliferation of undersized prop roots
Twisting or curling the pneutophores
Presence of adventitious aerial roots
Death of prop root tips fissuring or pealing of
Abnormal branching of prop tips
Gross physiology
Abnormal increase or decrease in osymolyts
Increased stomatal resistance
Decreased stomatal conductance
Reduced transpiration and CO2 uptake
Delayed chlorophyll activation
Abnormal increase or decrees in respiration
Reduced rate of sap flow in primary trunk
Increase salt concentration in soft tissues
Increase concentration of abscisics acid in tissues
Management Failure. The mangrove forest is disappearing because of the three main
management failure reasons: lack of skilled and well trained officials and failure of
institutions to effectively manage coastal mangrove resources and conflicting activities,
poor planning and knowledge of coastal land use and implementation of development
plan that does not include environmental protection principals.
Poor Knowledge of Mangrove Ecosystem and High Dependence of Local
Population on its Products and Services. The people who live near the mangrove
forest and depend on the mangroves for their livelihoods do not have enough knowledge
and education regarding the value of mangroves. They do not know how to conserve the
mangrove forest thus they lead to the destruction of the forests resources.
Other Uses. Mangrove wet land have been used for other natural resources. Population
is increasing day by day putting under pressure food production; mangroves are often
converted to salt pans, agricultural fields and aquaculture farms. A mentionable amount
of mangrove forest has been converted into salt production area in Mohesh Khali, Cox’s
Bazar. Many natural mangrove stands are also degrading from overgrazing. Mangrove
leafs are excellent food for domestic animals such as goat, cattle, sheep and cow and
local people can easily put their livestock for feeding to the mangrove forest.
Diseases. “Top dying” is the disease of the dominant Sundari trees (Heritiera fomes)
one of the big causes for deteriorating the forest. At least 5-6% of the total H. fomes
across the Sundarban is now suffering from the disease and around 50% of them have
already been affected in most areas of high salinity. According to the Forest Department,
spreading of “top dying” started on a large scale since 1980 (see Figure 3). Recent index
also shows that approximately 70% of H. fomes stems are moderately or severely
AACL Bioflux, 2010, Volume 2, Issue 3. 83
affected by “top dying” (Islam & Wahab 2005). A survey conducted by the Forest
Department of Bangladesh from 1994 to 1996, showed that on an average 134291.701
m³ of H. fomes die from the disease every year and thus the disease poses a significant
cause in terms of economic and biodiversity losses. According to the Forest Department
Research Centre of Bangladesh, accepted salinity levels in the rivers and canals are 5-
10% and in rivers and canals in the Satkhira Range of the Sundarban is 27-33%. Rising
salinity in rivers, canals and other water bodies in the mangrove forest is one of the big
threat for the death of trees.
Figure 3. Compartment map showing the spreading of “top dying” disease affecting
H. fomes from 1983 to 1995 (shaded areas) (after Iftekhar 2004).
A number of diseases has been identified as chief causes of population decline of the tree
species Avicennia spp., Rhizophora spp., Heritiera spp., Pandanus spp., Phoenix spp. and
Acanthus spp.. Data are scarse on disease problems of Nypa spp., Ceriops spp.,
Excoecaria spp., Bruguiera spp. and Sonneratia spp. Certain important diseases of
Sundarban mangroves are leaf blight (Alternaria alternata (Keissl, 1912)), Dieback
(Phytophthora nicotianae (Breda de Haan, 1896)), stump and collar rot (Fomes spp.) and
damping off (Pythium spp. and Phytophthora spp.) affecting Avicennia spp.; Leaf spot
(Cercospora rhizosphorae), trunk gall and decline (Cylindrocarpon didymum (Wollenw,
1926)), prop root rot (Capillataspora corticola (Hyde, 1989)) and seed rot (Fusarium
spp.) affecting Rhizophora spp.; Wilt (Fusarium oxysporum), quick decline and lethal
yellowing (Mycoposma like bodies), leaf blight (Gliocladium versoeseni), bleeding disease
(Ceratocystis ulmi (Brisman, 1918)), leaf necrosis (Pestalotia spp.). Affecting Phoenix
spp.; Dieback (Fomes spp.) and other diseases affecting Heritiera spp.; Leaf spot
(Alternaria tenuis (Nees, 1817)), anthracnose (Glomerella cingulata (Spauld. & Schrenk,
1903)), leaf blight (Botrydiploida theobromae and Phyllosticta spp.), sootymold (Meliola
spp.), leaf and fruit rot (Erwinia carotovora var carotovora), Cadang cadang (Unkonwn
aetiology) affecting Pandanus spp.; Mosaic (virus), leaf blight (Septoria acanthii),
powdery mildew (Oidium spp.), rusts affecting Acanthus spp. and sooty mold affecting
Aegiceras spp.(Banerjee et al 1991).
Fire. Fire may have caused some of the most serious damage of the mangrove
ecosystem in recent years. Trees in an area around one km2 at Napitkhali under
Chandpai range of the world's largest mangrove forest are burning rapidly, posing a
threat to natural habitat for many rare species including the famous Royal Bengal tiger.
AACL Bioflux, 2010, Volume 2, Issue 3. 84
On March 20, 2010, trees and animal habitats of around 250 ha of the forestland were
destroyed by fire. In the last three years, 12 incidents of fires occurred in the Sundarban
(MAP 2010). The mangroves are the main source of honey and wax in Bangladesh. The
technique of honey and wax collecting is very ancient. Das & Siddiqi (1995) reported that
200 metric tons (MT) of honey and 55 MT of wax are collected annually from the forest
The Sundarban inhabit numerous species of trees that produce abundant nectar and
pollen and these floral resources are used by honey bees (Islam & Wahab 2005), in order
to remove the honey bees from the nest, fire has to set up. However, sometimes the fire
spreads destroying the larger areas of the forest.
2. Natural Causes
Natural Disasters, Climate Change and Sea Level Rise. Various natural calamities
like cyclone, flood, storms, coastal erosion, naturally shifting hydrology, climate change
and sea level rise may destroys trees and animals even faster. The damage to Sundarban
caused by recent cyclone Sidr has been preliminary assessed at $142.9 million. It has left
26 % of the forest severely damaged (Saadi 2010). Climate change is set to damage
biodiversity of the Sundarban increasing the immersed areas and salinity of water in
coastal areas. As a result, a wide range of impacts on socio-economic scale and on the
mangrove ecosystems is anticipated, including the increased damage to crops, fisheries,
forests and livestock. A report by UNESCO, entitled "Case Studies on Climate Change and
World Heritage", has stated that an anthropogenic 45 cm rise of sea level (likely to
happen by the end of the twenty-first century, according to the Intergovernmental Panel
on Climate Change), combined with other forms of anthropogenic stress on the
Sundarban, could lead to the destruction of 75 % of the forest (UNESCO 2007). Natural
resources of the Sundarban, especially various species of trees, are seriously threatened
due to sea level rise. Low areas of the mangrove forest are flooded by tidal waters every
year because of sea level rise along with and massive silt deposition. Rising seas are said
to have flooded 7,500 ha of mangroves in the Sundarban (WWF 2007). Mangrove forests
require stable sea levels for long-term survival. They are therefore extremely sensitive to
current rising sea levels caused by global warming and climate change. Rising sea levels
have submerged two islands in the Sundarban, and a dozen more are under threat of
submergence. Global warming is expected to cause changes such as higher
temperatures, sea level rise and changing rainfall patterns, as well as more abrupt
effects, such as an increase in the intensity and frequency of extreme events such as
floods, storm surges and cyclones and sea level rise. Climatologists so far agree that sea
level will increase 9-88 cm over 1990 levels by the end of the century. Dasgupta et al
(2007) reported that the largest percentage share of land area impacted by sea level rise
was evident in Bangladesh throughout south Asia (Figure 4).
Figure 4. Percentage of land area impacted by sea level rise among south Asian countries
(after Dasgupta et al 2007).
AACL Bioflux, 2010, Volume 2, Issue 3. 85
3. Other Causes
Other Causes behind mangrove forest deterioration are loss of soil fertility,
geomorphological changes, high salinity ecological succession, inadequate regeneration
and low yield (Akhtaruzzaman 2000).
Present Mangrove Management in Bangladesh. The management history of the
Sundarban mangrove is very old. Mangrove forests of India and Bangladesh, were
managed since 1769 and detailed work-plans were prepared during 1893–1894
(Chowdhury & Ahmed 1994). Forestal forestry carried out a detailed scientific inventory
of the mangroves of Sundarban. Choudhury prepared the working plan based on
inventory of Sundarban for the period 1960 to 1980 (Choudhury 1997). The main
objective was to manage the forest on a sustained yield basis. In 1993, the Forestry
Master Plan suggested two sanctuaries. The first one proposed annual planting target of
about 18,000 ha during 1993–2002 and 21,000 ha during 2003–2012 (MOEF 1993).
However, sufficient attention has not been given to the use of quality planting material,
site preparation and post-establishment maintenance. Due to financial and legal
constraints enough protection of plantations from fire, grazing, illegal removal and
encroachment has not been provided (GoB 1993). The second sanctuary paid attention to
the development of wildlife sanctuaries; consequently, three areas of the Sundarban
Forest Division have been declared wildlife sanctuaries. However, the total area of these
sanctuaries is not sufficient to provide long-term protection to the wildlife (Islam &
Wahab 2005). An integrated management plan for the Sundarban is being prepared
through a FAO project. The major objective is to achieve sustainable management of the
mangrove in order to yield different important recourses including wood, fish, wild life as
well as recreation services and non-wood products (Choudhury 1997). However,
mangroves are now degrading rapidly. Forest cover, species diversity and ecosystem
function have declined, even though several forest policies, laws and management plans
have been enacted to protect them. The effectiveness of these policies and plans is
limited by the poor implementation capacity (Iftekhar & Islam 2004). In addition to
natural forest, mangrove plantation programme has been undertaken over an area of
170,000 ha since 1966. Sonneratia apetala (Buch.-Ham 1822) and Avicennia officinalis
(Linnaeus, 1775) are the principal planting species for the coastal afforastation. But
neither tree cutting moratorium nor participatory forestry have seen any success.
Moreover, negligence and corruption among the personnel of government forest
department along with the collaboration of local political leaders with the encroachers is
adding to the management failure (Akhtaruzzaman 2000). Although governmental bodies
(e.g. Bangladesh forest department) tried to undertake certain conservation planning
initiatives such as Environmental Policy, National Conservation Strategy and National
Environmental Management Active Plan to protect mangrove ecosystems since 1960 to
2001, management strategies based on logical and scientific basis have not been
developed until today. Adequate research efforts have not yet been paid to find out
effective management policies (Islam & Wahab 2005).
Examples of Sutainable Mangrove Management in South Asia. The Matang
mangroves in Malaysia is the best example of mangrove management in the world.
Comprehensive management objectives and a ten-year working plan have contributed to
its success. The 90% of total area is now covered by natural regeneration and
repopulation is assisted by artificial planting (Chan 1996). In Vietnam, the “3.2.7 project”
and the “5 million haproject” are examples of national projects under auspice of the
government. Today, 10 million haof reforestation including mangrove and other plants is
being undertaken (Kogo & Kogo 2004). In China, Hong Kong, Shenzhen, Fujian,
Dongzhai and Guangdong provincial governments introduced sustainable management
practices during the last few years (Chen et al 2004). Forty years ago, Jiulongjiang
estuary mangrove forest was completely destroyed by human activities. However, the
Chinese government took the initiative to regenerate the mangrove forest. Chinese
Mangrove Protection Project (CMPP) works on mangrove issues is all China's coastal
provinces which have mangroves including Zhejiang, Fujian, Guangdong, Hainan and
AACL Bioflux, 2010, Volume 2, Issue 3. 86
Guangxi. Activities include awareness raising investigation, scientific research,
communication, interpreter training, data accumulation, web construction, afforestation
and the Greenwild Mangrove Fund (GWMF) in order to promote mangrove conservation
and management of Chinese mangrove ecosystems (MAP 2007). As a direct result of
these comprehensive measures, Jiulongjiang estuary mangrove forest is now a large
mangrove wetland; Moreover, the government introduced sustainable management
system (Chen et al 2004; Peng 2000). Wang Mangrove Reforestation Contract Project in
the Philippines archived the highest success of sustainable management of the resource.
In Indonsia, a new approach called Tambak empang parti (channel fish ponds) has been
introduced to the north cost of west Java to take socio-economic factors in account
(Soegiarto 2004). The ‘Perrum Perhutani’’ is another positive management example in
Indonesia. Almost 3,000 ha of damaged mangrove forest have been rehabilitated in
Cilacap on the south coast of Java. In addition, Thailand, Ghana, Senegal and Tanzania
provide success stories of community based management of mangrove resources.
Conservation and Sustainable Management Issues. Internationally, forest
ecosystem management attention seems now to have generally been shifted from
management for a single objective (often wood production) to a sustainable ecosystem
approach that tries to incorporate the principles of equity in resource utilization and
participation for sustained production of multiple outputs into forest management by
recognizing the hopes and aspirations of different stakeholders interested in the future of
the natural forest resources. Environmental destruction in a country or region affects
other regions. Conservation of nature at local level strengthens and contributes towards
regional and global nature conservation. At international and national policy level, it is
today accepted that Sustainable Forest Management (SFM) depends upon several factors
such as: 1. integrated management for all forest values–wood and other items and
services, 2. meaningful participation of all stakeholders 3. landscape level planning and
management and 4. comprehensive monitoring, evaluation and reporting on indicators of
sustainability. Most of the mangrove forests in Bangladesh are now substantially
degraded and poorly stocked. In this crucial time it is needed to review the current
management strategy of mangrove forest ecosystem for the future betterment. The
future of this ecosystem depends on wether sustainable planning and management can
be effectively implemented (see Figure 5).
To protect and conserve the Sundarban mangrove of Bangladesh, the following
measures should be considered: silvicultural system must be improved to promote
effective regeneration. At the same time, sustainable alternatives to forest-based
livelihoods such as home gardening, forest product based small cottage industry, bee
keeping, poultry farming, tourism and recreation may be explored. The study
demonstrated that the traditional resource users possess distinct customary ways to
sustainably manage the resources of the Sundarban. Thus these practices should be
promoted.Technical and institutional education and training can also create alternative
job opportunities. To formulate such management strategies, growth and yield
information should be made available through appropriate forest inventory that would
allow computation of annual allowable cut that can be extracted from the mangrove
forests preserving sustainability of ecological, economical and social values of these
forests. Also, an accurate inventory of encroached mangrove forest is required to develop
a viable land recovery plan. In addition, it is required to develop comprehensive
protection measures to tackle the illicit activities such as forest land encroachment for
agriculture, illegal tree felling, wood smuggling, poaching of wildlife etc. There is an
urgent necessity to strengthen the management of mangrove forest through recruiting
well trained and motivated forestry professionals, allocating sufficient budget and
developing infrastructures. The Sundarban mangrove forests must be brought under
community reserves where local people could be made partners in conservation and
management processes. Ecofriendly, cost effective technology such as phyto-remediation
and bio-manipulations should be considered for pollution prevention, control, and
remediation. Economical, yet efficient, industrial effluent treatment plants should be
utilised to reduce the environmental impact of industrial effluents. Use of mangrove
AACL Bioflux, 2010, Volume 2, Issue 3. 87
areas for dispersal of urban and industrial waste should be prohibited. Currently, there is
no organized system of harvesting wood, wild medicinal and aromatic plants. There is a
need to formulate policies related to rotational harvest of medicinal plants for the benefit
of communities thereby controlling excessive pressure on the mangrove forest.
Figure 5. Sustainable management plan for mangrove forest ecosystems.
Public awareness and campaign
2. Video and slide shows
3. Publications on the importance of
sustainable development of mangrove forest
4. Sustainable usages of renewable resources
and their conservation
Monitoring, evaluation, reporting and
1. Estimation of forested area and inventory of
2. Ecosystem health and vitality
3. Comprehensive protection management
4. Monitoring of timber harvest including
5. Survey of forest regeneration status and
Scientific research and planning
1. Research on eco-physiological functions,
ecosystem productivity management, genetics
and taxonomy
2. Identifying and monitoring biodiversity
3. Identifying and understanding threats to
mangrove forest
4. Development of sustainable technologies
5. The effects of the global climate change on
the forests
6. Pest and disease control and management
7. Pollution prevention, control, and
8. Integrated conservation and management
mangroves and aquaculture
Ecological regeneration and extension of
forest cover
1. Improve silvicultural system to promote
effective regeneration
2. Extension of forest area and type of forest
cover (e.g., natural forest, man-made forest)
Adequate of policy, legal and institutional
1. Formulation of adequate rules and
2. Capacity building
2. Conflict resolution mechanism
3. Efforts to reduce all threats on forests
4. Mechanism for protection, management and
benefit sharing
5. Accountability and financial transparency
Meaningful participation of all key
1. Local communities
2. Forest officials
3. Governmental agencies, national and
international institutions including local NGOs
4. Local policy makers (e.g., representative of
local governments such as Upazila Parishad)
5. Participation and empowerment of women
AACL Bioflux, 2010, Volume 2, Issue 3. 88
Conclusions. The deterioration of mangroves can lead to serious consequences,
including reduction in biodiversity, species decline, genetic erosion, extinction, increased
flooding, and decline in water quality.The future existence of Sundarban mangrove forest
in Bangladesh depends on the development and successful implementation of a
sustainable management plan to protect and conserve these important resources. The
government has attempted to introduce some initiatives to protect these important
ecosystems but the sustainability of these resources could not be achieved due to lack of
sound management strategies. A sustainable management plan should be developed by
involving all beneficiaries and stakeholders and should be effectively implemented to
conserve the world’s largest mangrove ecosystem for present and future generations.
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Received: 01 February 2010. Accepted: 27 April 2010. Published: 27 April 2010.
Mohammed Mahabubur Rahman, Graduate School of Intregrated Arts and Science, Faculty of Agriculture, Kochi
University, 200 Monobe, Nankoku, Kochi, Japan, 783-8502,
Md. Motiur Rahman, Silvacom Ltd., Edmonton, AB T6E 5K5, Canada. E-mail:
Kazi Shakila Islam, The School of Oceanography and Environmental Science, Xiamen University, Xiamen,
Fujian-361005, P.R. China.
How to cite this article:
Rahman M. M., Rahman M. M., Islam K. S., 2010 The causes of deterioration of Sundarban mangrove forest
ecosystem of Bangladesh: conservation and sustainable management issues. AACL Bioflux 3(2):77-90.
... The resources of the Sundarbans have been declining gradually (Iftekhar & Islam 2004;Gopal & Chauhan 2006;Giri et al. 2007Giri et al. , 2015Rahman, Rahman & Islam 2010;Rahman & Asaduzzaman 2010;Uddin et al. 2013;Aziz & Paul 2015;Sarker et al. 2016). The forest structure is becoming simpler and the average height of the trees is decreasing, causing a decline in habitats for birds, monkeys and other treedwelling species. ...
... A few studies show that the existence of organized groups of mongers who illegally cut and remove valuable trees are acutely prevalent in the Sundarbans (Rahman, Rahman & Islam 2010). The forest department allows illegal means of fishing by taking bribes from the fishermen (Hassan, Nabi & Mozumder 2012). ...
... Accordingly, biodiversity degradation not only occurs due to the non-existence of markets, but also because of unequal power distribution among different groups. Thus, infiltration and illegal removal of valuable wood from the forest occurs due to the absence of sustainable management practices and well-functioning institutional arrangements (Rahman, Rahman & Islam 2010). ...
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This study captures and depicts the understanding on multiple values of nature (MVN) by traditional resource users (TRUs) of the Sundarbans. The research, using multiple evidence-based approaches, combining participatory insights of the TRUs of the Sundarbans and interdisciplinary heterodox perspectives, demonstrates that valuation of environmental resources through market penetration pricing does not reckon the social benefits and values coproduced through complementarity between humans and nature. The TRUs of the Sundarbans treat the forest as their mind, through which human-nature sociality flourishes. The traditional knowledge system can significantly contribute to the sustainable management of biodiversity resources, both within the protected areas system and potentially within other effective area-based conservation measures, if given a chance and supported by governmental and non-governmental agencies. Moreover, TRUs argue that due to lack of a proper market structure and equal distribution of power, rents are dissipated through market pricing, going into the pockets of the rent-seeking powerful class. This rent-seeking behaviour induces unproductive, expropriating activities that bring positive returns to the individual but not to society. Dividing the tranformational pathways into three phases-stabilization, transformation and sustainability-this chapter argues that such processes require approporiation of nature, as oppossed to expropriation, for harmony of nature with people.
... Degradation refers to damage or reduction in quality of certain features of the forests. Forest degradation is often difficult to discern because changes may be subtle (Rahman and Islam, 2010). This does not involve a reduction of the forest area, but rather a quality decrease in its condition. . ...
... Bangladesh is a developing country having 14.4 million hectares of total geographic area (Islam et al., 2005). Of t hem, 13.36 million hectares are land surface, and 0.94 million hectares are rivers and other in-land water bodies (Rahman et al., 2010). ). ...
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Please cite this article as: S. Murshed, A.L. Griffin, M.A. Islam, et al., Assessing multi-climate-hazard threat in the coastal region of Bangladesh by combining influential environmental and anthropogenic factors, Progress in Disaster Science (2022), https://doi. Abstract This study developed a geo-spatial framework for assessing multi-hazard threat in Bangladesh coast, integrating environmental hazards (EH), geo-environmental attributes (GA), and anthropogenic modifications (AM) based on their potential contribution to overall threat. For this purpose, fuzzy logic based analytical technique was integrated with geospatial mapping. Thematic layers were prepared for twenty-three theoretically important factors representing the three components of threat. The spatial variations of threat and its components were delineated through spatial overlaying of the respective layers in GIS environment. The final threat map revealed 32% (5338 km 2) and 4% (646 km 2) of the area of the western deltaic coast, which encompassed more than 50-60% of the areas of Khulna, Bagerhat, and Satkhira districts, was under high and very high threat, respectively, owing primarily to frequent cyclones, salinity ingression, and subsidence, and secondarily to the low elevation of the coast, high astronomical tide, shallow bathymetry, excessive groundwater extraction, and polder construction. High and very high threat zones within the central estuarine coast corresponded to 27% (4518 km 2) and 16% (2618 km 2) of the area, including most of Bhola, Barguna, and Patuakhali districts, which was attributable to the effects of coastal erosion, sea-level rise, flooding and the ancillary effects of strong wave action, high river discharge, deforestation, and land transformation. Around 14% (948 km 2) and 3% (164 km 2) of the eastern cliff coast, comprising the southwestern part of the Coxsbazar district, was found to be under high and very high threat, respectively, due to the direct effects of sea-level rise, storm surge, erosion, and indirect effects of closeness to the shoreline, alluvial composition of the beach, tourism, and pollution from industries. The outcomes of this study could guide the coastal managers of Bangladesh in prioritizing actions aimed at disaster risk reduction and sustainable development of this region.
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The mangrove biodiversity declination is a source of concern to researchers around the world. The biodiversity of the Sundarbans is declining day by day like all the forests of Bangladesh. This study will provide you with a brief overview of the significant surveys of the Sundarbans from 1892 to 2016. It will also be possible to find out the reasons behind the destruction of biodiversity in the Sundarbans. A brief suggestion of what steps we should take to protect biodiversity is discussed.
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The overall objective of the study was to examine the pros and cons of the participatory approach adopted in natural resource management in the ecologically protected areas of the Sundarbans mangrove of Bangladesh. A comparative study was done between the people who are involved and non-involved in this approach. Empirical data was collected through personal interviews with a structured questionnaire. The Gini coefficient was measured first and then embedded with the Lorenz curve to draw a line between perfect equality and inequality vis-a-vis. The study revealed that the co-management built awareness in favor of biodiversity conservation and the efficient use of natural resources. Contradictorily, a segment of different hierarchical committees was involved in destructive activities like poisoning the wetlands for fishing. Therefore, a mixed outcome was found. The findings will help the policymakers in identifying the pitfalls and bottlenecks rooted in co-management. Hence, the study recommends revising the approach to ensure the community’s active participation on an equal basis and take action against them who degrade those resources. Exploring profitable alternative income-generating activities is warranted to narrow down the dependency on the Sundarbans mangrove’s natural resources. In order to address the tragedy of the commons, the study advocates for the unity of all knowledge ranging from science to humanistic scholarship for sound policymaking.
Human-induced wetlands are more exposed to threats around the world. For conserving and protecting wetland resources, such as mangrove forests, it is significant to monitor the wetlands and their associated land features and land cover use. The land use and land cover (LULC) changes with remote sensing have been used with different aspects to evaluate the wetland's change dynamics in many areas. This study used four satellite images of Landsat 5 and 8 for LULC mapping of mangrove wetlands and their adjacent areas to evaluate the change dynamics for 1990, 2000, 2010, and 2020. During the period 1990 to 2020, significant changes in land features have been observed. The LULC analysis revealed a remarkable increase in aquaculture and a significant decrease in agriculture. The NDVI (−0.08 to 0.35) and NDWI (−0.10 to 0.32) indices analysis also visibly confirmed changes in land features. The aquaculture area was increased by 5686 ha (∼230%), whereas the agricultural area decreased by 6682 ha (∼66%) in 2020 compared to 1990. The analysis also found a decrease of 1881 ha (∼14%) of the forest area for the same period. A decrease in agricultural lands and an increase in aquaculture areas indicate that inhabitants in the area change their profession over the period. This transformation has negatively impacted human-induced activities in the ecosystem and biodiversity of mangrove forests. The biodiversity welfare of natural wetlands, such as mangrove forests, is gradually reduced because of human interventions in the study area. Therefore, appropriate measures need to be imposed to improve the condition of mangrove forests and protect forest biodiversity.
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The Indian Sundarbans, together with Bangladesh, comprise the largest mangrove forest in the world. Reclamation of the mangroves in this region ceased in the 1930s. However, they are still subject to adverse environmental influences, such as sediment starvation due to migration of the main river channels in the Ganges–Brahmaputra delta over the last few centuries, cyclone landfall, wave action from the Bay of Bengal—changing hydrology due to upstream water diversion—and the pervasive effects of relative sea-level rise. This study builds on earlier work to assess changes from 2000 to 2020 in mangrove extent, genus composition, and mangrove ‘health’ indicators, using various vegetation indices derived from Landsat and MODIS satellite imagery by performing maximum likelihood supervised classification. We show that about 110 km2 of mangroves disappeared within the reserve forest due to erosion, and 81 km2 were gained within the inhabited part of Sundarbans Biosphere Reserve (SBR) through plantation and regeneration. The gains are all outside the contiguous mangroves. However, they partially compensate for the losses of the contiguous mangroves in terms of carbon. Genus composition, analyzed by amalgamating data from published literature and ground-truthing surveys, shows change towards more salt-tolerant genus accompanied by a reduction in the prevalence of freshwater-loving Heiritiera, Nypa, and Sonneratia assemblages. Health indicators, such as the enhanced vegetation index (EVI) and normalized differential vegetation index (NDVI), show a monotonic trend of deterioration over the last two decades, which is more pronounced in the sea-facing parts of the mangrove forests. An increase in salinity, a temperature rise, and rainfall reduction in the pre-monsoon and the post-monsoon periods appear to have led to such degradation. Collectively, these results show a decline in mangrove area and health, which poses an existential threat to the Indian Sundarbans in the long term, especially under scenarios of climate change and sea-level rise. Given its unique values, the policy process should acknowledge and address these threats
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The natural ecosystem of the Sundarbans mangrove wetlands is under threat due to anthropogenic activities. This ecosystem has become vulnerable to pollution such as oil spillage, heavy metals, and agrochemicals – which may have changed the mangrove ecosystem’s biogeochemistry. In this paper, the present status of Sundarbans’ mangrove pollution is reviewed. The ecotoxicologic effect on its aquatic and terrestrial flora and fauna, and pollution management problems are also discussed. Conservation and environmental pollution management for protecting this worlds’ largest mangrove ecosystem are immediately needed. Environmentally sound technology should be adapted for pollution prevention, control and remediation in the Sundarbans mangrove wetlands.
This article presents the status of Bangladesh forestry explaining the needs of forest products and the efficiency of forest policy and management practices, and relates sustainability with scarcity situations. The status of forestland use was explained by compartmentalization of indicators into resource factors and social factors. Three indicator groups were used to present the resource and social factors of Bangladesh forestry. The findings suggest that forest sustainability depends not only on resource criteria but also on social criteria. The study also explores how resource and social factors need to be explored for sustainable practices.
Despite the recent better understanding and awareness of the role of mangroves, these coastal forest communities continue to be destroyed or degraded (or euphemistically reclaimed) at an alarming rate. The figure of 1% per year given by Ong (1982) for Malaysia can be taken as a conservative estimate of destruction of mangroves in the Asia-Pacific region. Whilst the Japanese-based mangrove wood-chips industry continues in its destructive path through the larger mangrove ecosystems of the region, the focus of mangrove destruction has shifted to the conversion of mangrove areas into aquaculture ponds and the consequences of the unprecedented massive addition of carbon dioxide to the atmosphere by post industrial man. Mangroves are non-homogeneous; characterised by distinct vegetative zones that occupy the interface between and and sea and dynamically interacting with the atmosphere above as well as with the influences of the adjacent land and sea. The conservation of mangroves should thus include not only the various vegetation and tidal inundation zones but also the adjacent marine and terrestrial areas (including the water catchment area). On the current concern with global climate change, it is pointed out that relative sea level change is very much site dependent. For effective planning and management, it is vital to know if a particular site is stable, rising or sinking so efforts should be directed to find suitable methods for determining this. However, should rapid relative sea level rise take place, there is very little likelihood of saving mangroves whose landward margins have been developed by man, a fact to bear in mind when selecting sites for conservation. The Matang mangroves of Malaysia is a rare case of successful sustainable management of a tropical rain forest. Although the tools of management are available they are not widely applied. We particularly urge the Japanese mangrove wood-chips industry to look to long term sustainable use rather than short term gains. A suggestion is made to appeal to the new Government of Japan to take the lead in environmental friendliness especially to the rain forests of the Asia-Pacific region.
The mangrove forest of Bangladesh, the largest continuous mangrove bulk, is one of the most important features of the coastal area of the country. The existence of the mangrove has increased the values of other coastal and marine resources such as the coastal and marine fisheries by increasing productivity and supporting a wide biological diversity. The deltaic mangrove of Bangladesh is ecologically different from the other, mostly nondeltaic mangroves of the world and is unique also in its floral and faunal assemblage; therefore, a number of endangered plants and animals that are extinct from other parts of the world, are existing in Bangladesh mangrove. However, the mangrove has been under intensive pressure of exploitation for the last few decades which, in addition to direct clearance and conversion have placed the mangrove under extreme threat. Shrimp farming is the most destructive form of resource use the mangrove has been converted to, which contributed significantly to mangrove destruction with a corresponding loss of biological resources. Concerns have been raised among the ecologists, biologists, managers and policy makers since the early 1990s; deliberate destruction of mangrove and unplanned development of coastal aquaculture particularly shrimp aquaculture have been put under extreme criticism and the sustainability has been questioned. The present status of the mangrove resources including mangrove fisheries and aquaculture and management practices have been reviewed in this paper; impacts of different forms of human interventions and resource use have also been discussed. It is suggested that the management options and the policy aspects should be critically reviewed and amended accordingly; beneficiaries and stakeholders at all levels of resource exploitation must take part and contribute to conservation and management. An immediate need for mangrove conservation has been identified.