Sundarban's Discription

Sundarban Area Map

 The Sundarbans is the world’s single largest mangrove forest. That extends across Bangladesh and Indian state of West Bengal. It is formed by the interplay of greater Ganga–Brahamputra estuarine system that supports brakish water environment. 62% area of the total Sundarbans is situated in Bangladesh and the rest 38%is in West Bengal. The forest is estimated to be five thousand three hundred years old and is unique reservoir of bio-diversity (Chowdhury 2001). Mangroves are the threatened coastal, deltaic intertidal halophytic plants, play very dominant and important roles in the estuarine mouths, sea land interphase areas or deltaic ecosystems of both the tropical and subtropical zones, especially, in the highly populated South East Asian countries, several Pacific Islands and Australian coasts. In spite of their important role and immense ecological impacts these mangroves and the mangrove ecosystems have faced both biotic and abiotic threat and these highly productive mangrove zones have been cleared or the mangrove ecosystems have also been degraded very rapidly during the last three centuries (Naskar et al. 1999).

Sundarban River Side

The forest Sundarbans is flat and its elevation is hardly three meters above mean sea level (Siddiqui 2001). The entire area is intersected by a complex network of streams and rivers varying considerably in width and depth (Choudhury 1968). At a comparatively recent period, all these rivers were connected with the Ganges. Now however, the only one which is a direct influence is the Baleswar which is responsible for fresh water supply in the eastern part of the Sundarbans. A number of the rivers namely Passur, Sipsah, Arpangasia, Malancha and to a slight extent the Jamuna and the Rainmangal have indirect connection and they receive overflow of the Ganges during rains. They also receive a considerable amount of local drainage throughout their long and meandering courses during the monsoon (Siddiqui 2001). Erosion and compensatory accretion are occurring continually along the banks of all larger rivers, but the rivers of the Sundarbans, are more stable than the main streams of the Ganges and the Brahamaputtra further east (Das and Siddiqui 1985). The floristic composition of the Sundarbans is rich compared to many other mangroves of the world (Choudhury 2001). Prain (1903a) recorded 334 species of plants belonging to 245 genera and 75 families for the Sundarbans and adjoining areas. Henning (1892) reported 70 species from 34 families for the entire Sundarbans (Indian and Bangladesh). Chaffey and Sandom (1985) presented a list of 66 species in the Bangladesh Sundarbans from 37 families.

Sundarban Sundari Tree

 Heritiera fomes (Sundri) and Excoecaria agallocha (Genwa) are the principal species of this forest.H.fomes constitutes about 65% of the total merchanttable timber. (i) H.fomes (Sundri), (ii) H.fomes (Sundri), – E. agallocha(Genwa), (iii) E.agallocha (Genwa) – H. fomes (Sundri),  and (iv) Ceriops decandra (Goran) – E. agallocha (Genwa) forest typc caovered 21%, 29.7%, 14.8% and 14.46% of area respectively (Siddiqui 2001). Other more important tree species include Xylocarpus  mekongensis (Passur), Avecennia officinalis (Baen), Amoora cuculata (Amur), Xylocarpus granatum (Dhundul), Sonneratia apetala (Keora), Rhizophora mucoronata (Garjan), Bruguiera gymnorrhiza (Kankra), Ageiceras corniculatum (Khalshi) (Rahman 1995).

Sundarban's Fisherman Casing Fish

 The Sundarbans is an important natural resource that provides a large number of products such as timber, pulpwood, fish, thatching materials, honey, bees wax shells etc. In addition it supports a very rich and diverse flora and fauna. It is the largest remaining habitat for the Royal Bengal Tiger. Some 600,000 people are directly dependent on this forest for their livelihood. In addition, the mangrove forest acts as a natural barrier to cyclones and tidal bores, and protects the densely populated agricultural areas to its north. The Sundarbans and the coastal plantations are important food source and breeding ground for off-shore fisheries, economic and commercial shrimp cultivation particularly in the south western districts of Bangladesh (Rahman 1995).

Mangroves, the sole vegetation of this area, constitute a very specialized forest ecosystem at the lands sea interface of the estuarine region in the tropical and subtropical countries. One of the important features of this area is the regular flooding by tidal water twice daily. The tidal water passing through the creeks, crevices inundate the lower part of the vegetation. This is a very dynamic ecosystem provide a unique opportunity for the interactions among plants, soil, adjoining water and aquatic living resource, for example-prawns, fishes and other biotic organisms and help to exchange different chemical indices and energy contents among themselves (Nanda 1999).

The freshwater flow from the upstream of the river Ganga is now reduced in comparison to the early 20th century; consequently the deltic lands in this lower Ganga basin of the Sundarbans tidal forests are now almost disconnected from many of these distributaries of the river Ganga. The reduced flow from the up stream has turned the tidal river water more saline, hampering the natural regeneration process of many important mangrove floras. Now-a-days, there is an alarmingly in creased population pressure on the natural virgin mangrove forests, severely affecting the regeneration process. Both the biotic and abiotic factors in this Sundarbans mangrove forest affected the natural growth and developmental process of mangrove flora (Naskar and Guha 1986).

Rayel Bengal Tihger of Sundarban

Although mangrove ecosystems have tremendous value for coastal communities and associated species, they are being destroyed at alarming rates (Shamsuddoha et al. 2007). Over at last 50 years, about one third of the world’s mangrove forests have been lost (Shamsuddoha et al. 2007). Human threats to mangroves include the overexploitation of forest resources by local communities, conversion into large scale development such as agriculture, fishery, salt extraction, urban development and infrastructure, and diversion of fresh water for irrigation (UNEP 1994). Mangrove flora is very specific for their salt tolerance habitats, tidal inundation, and salt elimination nature. Any changed soil and water conditions have severe effect on these mangrove flora and fauna. But unfortunately, the physiognomic features of the Sundarbans are very much interfered by human activities and mangrove forests are gradually getting eliminated from these areas (Naskar 1996).

Mangrove Forest of Sundarban

The greatest human treat to mangroves is the establishment of shrimp culture ponds. Because mangroves are often viewed as wastelands, many developing countries are replacing these forests with agricultural land and/or shrimp culture production. Shrimp culture pond accounts for the loss of 20 to 50 percent of mangroves worldwide (Primavera1997).Since all human society depend directly or indirectly on their ability to manage plants, animal and micro-organism effectively, the task of sustainable management of mangrove forest ecosystem is of paramount importance. According to Raven (1988) the most of world’s tropical forests will be destroyed or severely damaged within next 25 years, because of the explosive growth of human population in the tropics and subtropics, extensive and acute poverty in the region, and above all, collective ignorance of effective ways to manage tropical ecosystems so that they will be productive on a sustainable basis. 

International awareness focused on preserving biodiversity for immediate use for the future has gained momentum only in recent years (UNCED 1992). Genetic resources are a common heritage to mankind; they should be made available to promote development in present generations while, at the same time, their availability for the benefit of future generations must be assured. Bangladesh is unique in having diversified genetic resources in a range of habitats. The term genetic resources relates to actually or potentially useful characteristics (disease resistance, rapid growth, yield of quality factor or the presence or absence of chemical etc) of plants and animals those are transmitted genetically (FAO,1984). The main causes of resource depletion include degradation of natural forests, due to a combination of activities like urbanization, deforestation, jhooming, or intentional firing, improper land use and commercial logging, felling etc. At the beginning of the eighteenth century the forests are about double of the present conditions.

Sundri Tree's Root in Sundarban

The Bangladesh Sundarbans lies between the latitudes 21o 31` and 220 30` N and between the longitudes 890 and 900 E. It occupies a land of 401,600 ha, of which 395,500 ha are covered by forests (Chaffey et al. 1985), and comprises 44% of the total productive forest of Bangladesh (Anon 1989). Of the total area, approximately 70% are lands and 30% are waters. The distance between the northern and the southern boundaries averages about 80 km, although the distance between the extremities is about 100 km. The east to west distance within Bangladesh is about 80 km. The Sundarbans is bound by heavily populated agricultural land on the north and east, and by the Indian Sundarbans on the west. The Bangladesh Sundarsbans is a Reserved Forest and has been divided into four administrative Ranges with 55 Compartments. During the British period, i. e., before 1947, the entire Sundarbans was administered as a single Forest Management Division (Siddiqui 2001). Satkhira range is under Satkhira district is the South West region of Bangladesh. This area is polyhaline zone represents the western part of the Aura Sipsa and east of the Raimangal and is connected with the upper moribund part of the kobadak-Betna river system. The subsystem has its lost connection with the Ganges and does not receive any surface water flow from upstream except for local runoff (Hussain and Acharya 1994). It was found that the Sundarbans mangrove forest would be most severely affected by climate change. Due to a combination of high evapo-transpiration and low flow in water, the salinity of the soil would in increase.