Md. Mustafizur Rahman @ Rashed; Dept. of Zoology; Rajshahi University

“We portion out among them their livelihood in the life of the world, and We exalt some of them above others in degrees, that some of them may take others in subjection.” (Sura- Zukhruf: 32)

“Do they not see that We drive the water to a land having no herbage, then We bring forth thereby seed- produce of which their cattle and they themselves eat?” (Sura- As’sajdah: 27)

The Sunderbans Climatic condition Chief animal Species Effects of cyclone ‘SIDR’ in Sunderbans ecosystem Geographical presentation Individuality of Sunderbans Ecosystem of Sunderbans Sunderbans after ‘SIDR’ Derivation of name Personalities of mangrove plants Working of Sunderbans ecosystem Management of Sunderbans ecosystem Sunderbans in different time Major Flora of Sunderbans Economic significance Geology of Sunderbans Chief plant species Attractiveness Soil condition Major Fauna of Sunderbans Threats of Sunderbans

The Sunderbans:Sunderbans, the largest single block of tidal halophytic mangrove forest in the

world. With its collection of trees and wildlife the jungle is a showpiece of natural history. It is also a mid point of economic activities, such as extraction of timber, fishing and collection of honey. The forest consists of about 200 islands, separated by about 400 interconnected tidal rivers , creeks and canals. The vast mangrove forest listed as a World Heritage Site by the UN cultural organization UNESCO.Geographical presentation:

Sunderbans is positioned in the southern part of Bangladesh. It lies between the estuaries of the Meghna and Hugli (Hooghly) rivers (Ganges-Brahmaputra delta) at the point where it merges with the Bay of Bengal. It extends about 274 km (170 mi) along the Bay of Bengal and about 100 km (62 mi) inland. The forest lies a little south to the Tropic of Cancer between the latitudes 21º30´N and 22º30´N, and longitudes 89º00´E and 89º55´E. The total volume of this forest in Bangladesh is about 2316 sq. mile.

Derivation of name:The Bangla word ban means forest, and the name Sunderban

was coined either from the forests of Sundari tree i.e. Sundari-ban, or from the forests of the samudra (sea) i.e. Samudra-ban, or from its association with the primitive tribe Chandra-bandhe which was corrupted into Sunderban. The generally accepted explanation, however, is its derivation from the sundari tree, the most common tree in these forests.

Sunderbans in different times:Sunderbans was originally measured (about 200 years ago) to be of about 16,700 sq km. Now it has diminished to about 1/3

of the original size. Because of the partition of India, Bangladesh received about 2/3 of the forest; the rest is on the Indian side. It is now estimated to be about 4,143 sq km, of which about 1,874 sq km is occupied by water bodies. The forest lies under two forest divisions and four administrative ranges- Chandpai, Sarankhola, Khulna and Burigoalini and has 16 forest stations. It is further divided into 55 compartments and 9 blocks. The Sunderbans was declared as a Reserve Forest in 1875. About 32,400 hectares of the Sunderbans have been declared as three wildlife sanctuaries, and came under the UNESCO World Heritage Site in 1999. These wildlife sanctuaries were established in 1977 under the Bangladesh Wildlife (Preservation) (Amendment) Act, 1974. These are Sunderbans West (9,069 ha), Sunderbans South (17,878 ha), and Sunderbans East (5,439 ha).

Geology of Sunderbans:The band of the Sunderbans is of recent origin, raised by the deposition of sediments formed due to soil erosion in the

Himalayas. The process has been accelerated by tides from the sea face. The substratum consists mainly of Quaternary Era sediments, sand and silt mixed with marine salt deposits and clay. Geologists have detected a south-eastern slope and tilting of the Bengal basin during the Tertiary. Because of neo-tectonic movements during the 10th-12th century AD, the Bengal Basin titled eastward. Evidence

1

Characterizations of some important terms (definitions):Accipitridae: The family of predatory birds including hawks, eagles, and kites.Ecosystem: Ecosystem is a localized group of interdependent organisms together with the environment that they inhabit and depend on.Fauna: The animal life of a particular region or period, considered as a whole.Flora: Plant life, especially all the plants found in a particular country, region, or time regarded as a group.Food chain: Food chain is a hierarchy of different living things, each of which feeds on the one below.Food-web: The interlocking food chains within an ecological community Gastropod: Mollusk that has a head with eyes, a large flattened foot, and often a single shell, e.g. a limpet, snail, or slug. Halophyte: A plant capable of growing in salty soilMangrove: Mangroves are trees or bushes growing between the level of high water of spring tides and a level close to but above mean-sea level.Pelecypod: Saltwater or freshwater invertebrate animal that has its body contained within two shells joined by a hinge. E.g. oysters, mussels, and clams.

from borehole studies indicate that while the western side of the Sunderbans is relatively stable, the south-eastern corner is an active sedimentary area and is subsiding.Soil condition:

Soils of the Sunderbans mangrove forest vary from other inland soils in that they are subjected to the effects of salinity and water logging, which naturally affect the vegetation. In places soils are semi-solid and poorly consolidated. The pH ranges widely from 5.3 to 8.0. Although the Sunderbans soil is in general medium textured, sandy loam, silt loam or clay loam, the grain size distribution is highly variable. Silt loam is dominant textural class. Sodium and calcium contents of the soil vary from 5.7 to 29.8 meq/100g dry soil and are generally low in the eastern region and higher towards the west. The available potassium content of the soil is low, 0.3-1.3 meq/100g dry soil. Organic matter content varies between 4% and 10% in dry soil. Soil salinity increases from east (slight to moderate) to west (highly saline), but the salinity is not uniform from north to south throughout the forest.

Climatic condition:Since the forest is located on the south of the Tropic of Cancer and bounded by the northern limits of the Bay of Bengal, it is

classified as tropical moist forest. The temperatures in the Sunderbans are fairly equable than those of the adjacent land areas. The average annual maximum and minimum temperatures vary between 30º and 21ºC. High temperatures occur from mid-March to mid-June and low in December and January. The mean maximum temperature for the hottest months has been recorded as 32.4ºC at Patuakhali, in the east of the Sunderbans. The mean annual relative humidity varies from 70% at Satkhira to 80% at Patuakhali. Humidity is highest in June-October and lowest in February. Annual rainfall in the Sundarbans is in the range of 1640-2000 mm, rainfall increases from west to the east. Most rainfall occurs during the monsoon from May to October. Frequent and heavy showers occur from mid-June to mid-September. Often storm accompanied by tidal waves result widespread inundation and cause damage to vegetation and animal life. Individuality of Sunderbans:

Sunderbans, the littoral forest is the only ecological habitat of the tiger of its own kind not only in Bangladesh but also in the world except in India. The typical littoral forests of Sunderbans comprises of a host of trees species adopted to the peculiar estuarine condition of high salinity, lack of soil erosion and daily inundation by high tides. The tidal forms and the mangrove vegetation in Sundarban are responsible for dynamic eco-system vigorous nutrient cycling both terrestrial and aquatic. The whole eco-system is sensitive to change in salinity and the continuous cycle of erosion and deposition is affecting the plant communities giving rise to dynamic floristic changes. The plant communities are continuously adjusting to the new conditions. The uniqueness of the habitat is said to have contributed to certain behavioral trends, which are characteristic of Sundarbans tigers only. It is considered that man-eating propensity of tiger in this area is hereditarily acquired over a period of generations in the process of consumption of saline water. Cheetal, wild boar, rhesus macaque are the main prey species of tiger. Tiger fern (Achrostichum aureum) mostly covers the ground floor, which is common in saltwater and moderately saltwater zones. Tigers use these bushes to camouflage themselves. Aquatic animals like the crabs and fishes are also eaten by Sundarban tiger which occupies the pinnacle of both terrestrial as well as aquatic food-web. Sunderbans mangrove is the home of a number of endangered and globally threatened species. The Royal Bengal Tiger and the fishing cat are getting effective protection here. The creeks of Sundarbans form the home of Estuarine Crocodile, Salvator Lizard, River Terrapin and Horse Shoe or King Crab. This area serves as the nesting ground for endangered marine turtles like Olive Ridley, Green Turtle and Hawk's Bill Turtles. The aquatic endangered mammals like Genetic Dolphins thrive within mangrove creeks close to sea. A number of heronries form here during monsoon as well as during winter. It is home for Trans-Himalayan migratory birds. Personalities of mangrove plants:

Mangroves are halophytes: plants which naturally complete their life cycles under saline conditions. A saline environment poses a number of problems to the functioning of plants. In the first place uptake of saline water deregulates the osmotic pressure in the cells. The osmotic potential is generated by dissolved solutes in the cell sap. Thus, the intracellular concentrations of such solutes must increase with increasing salinity if cellular osmotic potentials are to be maintained. Mangroves, therefore, accumulate high concentrations of inorganic ions that function in the osmoregulation of leaves and other tissues. But too high concentrations of ions could have disastrous consequences for photosynthetic metabolism. Therefore, mangroves try to reduce internal salinity's. The structure of mangrove roots increases the availability of oxygen to roots growing in oxygen deficient sediments. The major feature of all these root systems is that the aerial roots are exposed to the atmosphere at least during periods of low tidal inundation. Such contact is essential because the diffusion of oxygen occurs 10,000 times more rapidly through air than through water The root system of most mangroves is shallow (generally less than 2 m).

Major Flora of Sunderbans: The vegetation of Sunderbans is largely of mangrove type and encompasses a

variety of plants including trees, shrubs, grasses, epiphytes, and lianas. Being mostly evergreen, they possess more or less similar physiological and structural adaptations. Most trees have pneumatophores for aerial respiration. The prominent species is Sundari and Gewa. The recorded species is 334 under 245 genera. Of these 17 are pteridophytes, 87 monocotyledons and the rest are dicotyledons. The plant species include 35 legumes, 29 grasses, 19 sedges, and 18 euphorbias. Of the 50 true mangrove plant species recorded, the Sunderbans alone contain 35. Almost all mangrove plant species are evergreen, dwarf, shrubby or tall trees, and grow gregariously without leaving any space on the floor. In the Sunderbans the saltwater forest is situated in the south-western part. The typical mangrove species dominate the central part of the forest. The moderate saltwater forest covers most of the southern parts of Khulna and

2

Bagerhat districts where Sundari is the dominant species. There is a thick mat of the nipa palm or 'Golpata' by the side of almost all the canals. Chief plant species:

Phyto-succession:The Sundarbans shows some distinct phyto-succession, where the newly formed lands are occupied by some pioneer

species- Arali (Leersia hexandra), wild rice (Potresia sp.), followed by Bain (Avicennia), Keora (Sonneratia) and Khulsi (Aegiceras). The secondary succession occurs due to Goran (Ceriops), Gewa (Excoecaria), Tunsha (Bruguiera), Sundari (Heritiera), Passur (Xylocarpus) and Jhana (Rhizophora). Major Fauna of Sunderbans:

The Sunderbans hosts a large variety of animals. It is the last stronghold of the Bengal tiger. Within the forest habitats there are about 50 species of mammals. About 320 species of birds of which over 50 species are known to be migratory (are mostly represented by the waterfowls). The egrets, storks, herons, bitterns, sandpipers, curlew, and numerous other waders are seen along the muddy banks. There are many species of gulls and terns, especially along the seacoast and the larger waterways. Accipitridae (kites, eagles, vulture, harrier etc) is represented by about 22 species. Nine species of kingfishers are available in the forest. The rich avifauna of the forest includes species of woodpeckers, barbets, owls, bee-eaters, bulbul, shrikes, drongos, starlings, mynas, babblers, thrush, oriole, flycatchers, and many others. Of about 50 species of reptiles, the largest member in the Sunderbans is the estuarine crocodile, some of which may attain a length of about seven meters. Although once they were abundant in this mangrove habitat, their total number is now estimated to be around 250. Species of lizards, including the Monitor Lizards, turtles, and snakes are well-represented. Only eight species of amphibians have been reported from the Sunderbans. The green frog is mostly observed in Chandpai area of the mangrove forest. The other forest amphibians include the Skipper frog, Cricket frog, Tree frog, and the common toad. The Sunderbans suports nearly 400 species of fishes in its varied aquatic habitats; these include both the pelagic and demersal fishes. Many species use these habitats as nursery grounds.

Among the invertebrates 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. Among the shrimps Penaeus monodon and Metapenaeus monoceros and the mud crab Scylla serrata are commercially important. Insects are varied, the most important being the honeybee Apis dorsata. The forest is very rich in its spider fauna (Araneae). Nearly 300 species under 22 families have been recorded from the mangrove forest habitats. Chief animal Species:

Animagroup

Local name Scientific name Animalgroup

Local name Scientific name

Fish

1. Rui2. Catla3. Ritha4. Koi5. Chital

1. Labeo rohita2. Catla catla3. Rita rita4. Anabus sp.5. Notopterus chital

Reptilia

1. Ozogor2. Gui sap3. Gokhra

4. Kumir5. Kachim6. Viper7. Krait

1. Python molurus2. Varanus salvator3. Ophiophagus Hannah,

Naja naja4. Crocodylus porosus

5. Batagur baska6. Vipera russellii7. Bungarus fasciatus

Amphibia

1. Bang 1. Euphlyctis hexadactylus, E. cyanophlyctis, Limnonectes limnocharis, Polypedates maculatus

Mammal

1. Bagh2. Horin

3. Banor4. Shukor5. Sheal6. Biral

7. Sojaru8. Sukor

1. Panthera tigris2. Cervus axis,

Muntiacus muntjak3. Macaca mulatta 4. Sus scrofa5. Canis aureus6. Felis chaus,

Prionailurus bengalensis

7. Hystrix indica8. Sus scrofa

Avis

1. Ghughu2. Chil

3. Tia4. Pacha

1. Streptopelia sp.2. Milvus migranus3. Psittacula sp.4. Bubo bubo

Natives:Only a few people live permanently in or around the Sunderbans. They include the bawalis (collectors of golpata), mouals

(honey collectors) and woodcutters. Their dwellings are usually at the edge of the forest and the houses are built on platforms supported on 3-5 m high poles of wood or bamboo. Some people, especially the bedyas (gypsy) live on boats.

3

Local name Scientific name Local name Scientific name

1. Sundari2. Gewa3. Goran4. Keora5. Amur6. Khamo7. Hantal 8. Golpata9. Dhundul

1. Heritiera sp.2. Excaecaria agallocha3. Ceriops decandra 4. Sonneratia apetala 5. Amoora sp.6. Rhizophora sp.7. Phoenix pelludosa 8. Nipa sp.9. Xylocarpu granatum

10. Bet11. Hogla12. Bon jhaw13. Akasbel14. Sornolota15. Manda16. Ora17. Passur18. Bain

10. Calamus sp.11. Typha sp.12. Tamarix sp.13. Cassytha sp.14. Cuscuta sp.15. Loranthus sp.16. Sonneratia caseolaris17. Xylocarpus mekongensis18. Avicennia sp.

Ecosystem of Sunderbans: Organisms living in the mangrove environment (Sunderbans) and all the physical parts (abiotic components) of that

environment which affect them mutually termed as the ecosystem of Sunderbans. Working of Sunderbans ecosystem:

In the Sunderbans ecosystem different mangrove plants use sunlight and non-living compounds (e.g. water, Oxygen, carbon-di-oxide, humic acid, nutrients etc.) to produce energy in the form of carbohydrates by photosynthesis. These Green plants like Liana, Grass, Fern, Goran, Golpata, Keora etc. make up the first trophic level and are known as primary producers. Primary consumers such as insects and many herbivores like cow, deer, pig etc. may feed on some of this plant matter, and are in turn eaten by secondary consumers, such as frog, tiger, lizard, crocodile etc. Falcon, Snakes etc. may play the role of the tertiary consumer by catching and eating secondary consumers like frog. Bacteria and fungi may then feed upon and decompose the falcon carcass, enabling the valuable nonliving components of the ecosystem, such as chemical nutrients, to leach back into the soil and water, where they can be absorbed by the roots of plants. In this way nutrients and the energy that green plants derive from sunlight are efficiently transferred and recycled throughout the ecosystem. Some or all of these trophic levels combine to form a food web, the ecosystem’s mechanism for circulating and recycling energy and materials. In addition to the exchange of energy, ecosystems are characterized by several other cycles. Elements such as carbon and nitrogen travel throughout the biotic and abiotic components of an ecosystem in processes known as nutrient cycles. For example, Nitrogen cycle, Carbon cycle, Water cycle etc. Every  ecosystem is characterized by a disturbance cycle, a regular cycle of events such as storms, floods, and landslides that keeps the ecosystem in a constant state of change and adaptation. Sunderbans also characterized by the disturbance cycle.Economic significance:

The most important value of the Sunderbans is its protective role. It helps hold coastlines, reclaim coastal lands, and settle the silt carried by the rivers. The estuary is a good breeding centre for many fishes. Several plant-based industries have been developed here. The most important ones are the newsprint and hardboard mills in Khulna. The raw material for the former is gewa and for the latter sundari. Other important plant-based industries are match factories and boat building. The forest is a good source of fuel, tannins, thatching, wooden articles, medicinal plants, and fodder. The forest is also a major source of honey and bee wax. Aegiceras corniculatum, Ceriops decandra, Nipa sp.Derris species and Hibiscus tiliaceous are the major honey plants.Attractiveness:

Most frequently visited sites in the Sundarbans include Katka, Hiron Point (known commonly as Nilkamal), Dublar Char and Tiger Point (Kachi Khali). Katka attracts tourists for its landscape and wildlife. There is a forest rest house here and an observation tower. Hiron Point also has a rest house and an observation tower. Dublar Char is an island with a beautiful beach. The other attraction of the island is the fishing activities that take place every year between mid-October and mid-February. Fishermen from other places of the country, especially from Chittagong gather here during the period to catch fish and dry them on the sunny beach. The honey collectors go into the forests during April-May. Annual income of Bangladesh government from this spot is about 6 to 7 crore Tk.Threats of Sunderbans:

Sunderbans is facing a serious threat to its ecosystem from poaching and rampant felling of trees. Most people in the region are poor and depend on the forest for livelihood and for their firewood needs. There is a major racket being run in the Sunderbans by timber merchants, who bribe forest officers and workers and get a free hand in collecting as much timber as they wish. Sundari tree was fast vanishing from the region as it had become one of the prime targets of the timber merchants. Another problem threatening the Sunderbans' mangrove ecology is the collection of tiger prawn seeds. The Sunderbans has a mono-crop agricultural pattern, which means that the people of the region have no alternative sources of income from farming. Thus, burdened by poverty, they have turned to collecting tiger prawn seeds, using nylon nets, which are dragged along the river banks. This is the most serious problem threatening the region. The situation has gone beyond control and is damaging the entire estuarine ecosystem of the area. The steady destruction of so many varieties of fish, in turn, has adversely affected animals, which depend on them. It is also threatening to endanger the different species of crocodiles, which form one of Sunderbans' major attractions. (Step by step the food chain of this ecosystem is breaking up, and its effects will only be understood later. The activity is also eroding the embankment, which protects villages in the region from floods. The increased exploitation of the forest is directly related to the decrease in the tiger population in the Sunderbans. Tigers are the best conservators of the forest. They keep human beings away. If there are no tigers in the Sunderbans, the forest area would be left bare in months. However, lack of food and excessive poaching are decimating the tiger population. Tiger poaching is taking place in the entire Sunderbans area. The price of its long-striped skin ranges from Tk. 200000 to Tk.600000 a piece. Its claws, tongue and testicles fetch high prices. According to informed sources, some of the biggest importers of tiger products from poachers operate through Chinese territory. Certain traditional Chinese and Korean medicines make use of tiger bones. West Asia is suspected to be another major destination for tiger fur. Because of poaching, the deer population is also declining rapidly. As a result, a large number of tigers, which feed mainly on deer, have moved to the adjoining forests of India. A recent study revealed that every day more than 23 kg of pollutants are dumped into the estuaries in the Sunderbans. Although the Sunderbans has an enormous capacity to absorb industrial effluents and other forms of pollutants, experts feel that if the present situation continues for long, it might affect the ecosystem adversely.Effects of cyclone ‘SIDR’ in Sunderbans ecosystem:

In November 2007 a cyclone has run through the low-lying watery edges of southern Bangladesh (mainly through the Sunderbans) with winds of about 250 km/s and causing a storm surge of 15 feet. It has caused great damages of the ecosystem of this forest. The rivers had swelled so high that water punched through mud embankments and washed away paddy and vegetable fields. Thousands of deer as well as many tigers and wild boar had been swept away by the massive tidal wave triggered by cyclone ‘Sidr’. The nests of many birds also have been destroyed. Wildlife becomes vulnerable to this sort of natural disaster. It also killed a great number (about 20000) of human. The storm flattened millions of trees (about 50, 00,000 trees of different species) and houses. The most effected plant is ‘Keora’. Innumerable bodies of the storm victims and cattle heads were floating on the shore of the Bay of

4

Bengal and in the rivers and ponds of coastal districts. The water bodies nearer the coast have been contaminated by salt water. In addition, dead human bodies and animal carcasses have also been found in water bodies, causing survivors to avoid them. As a result, crisis of drinking water occurred and a lot of organisms have lost their life. The sunderbans has lost its great bio-diversity.Sunderbans after ‘SIDR’:

After the cyclone ‘SIDR’ Sunderbans again attained the wave of life. It has started to bloom its God gifted beauty. New habitat and new environment arises. Plants started succession. Organisms have started chattering and fighting to survive in the after ‘SIDR’ environment.Management of Sunderbans ecosystem:

The benefit of an ecosystem is huge. But as human populations increase and their encroachment on natural habitats expand, humans are having detrimental effects on the very ecosystems on which they depend. The survival of natural ecosystems is threatened by many human activities. Many organizations and government agencies have adopted a new approach to managing natural resources (naturally occurring materials that have economic or cultural value, such as commercial fisheries, timber, and water) in order to prevent their catastrophic depletion. This strategy is known as ecosystem management. Using advances in the study of ecology to protect the biodiversity of an ecosystem, ecosystem management encourages practices that enable humans to obtain necessary resources using methods that protect the whole ecosystem. Ecosystem management often requires special measures to protect threatened or endangered species that play key roles in the ecosystem. So to protect the ecosystem of Sunderbans Bangladesh government has taken many steps. Some local and international NGO’s are also working for this purpose.

Sunderbuns, the god gifted natural place is our national wealth. It is full of great bio-diversity which is important for the nature and as well as for our own self also. Already it has attained the top most position as the natural wonder in the world by internet voting till today. We all should try our best to protect this natural spot. We should make this strategy from our heart. May Al-lah grant our commitment. ‘Amin’

“Dedicated to AL-LAH, Who has given me the power of expression”

Orientation: Microsoft Encarta Premium 2006 Banglapedia (National Encyclopedia of Bangladesh) 2006 Ecology O Poribesh Dushon. By, Shah Ahmed Nabi and AKM

Fazlul Karim Chowdhury Concept of Ecology. By, P.S. Verma and V.K. Agarwal

Reports of some national dailies Al Jazeera English - News Channel-i report Internet

5