The receives freshwater and sediment from a number of

The increasing salinity and pollution have also threatened the health of the forest. This is evident from
the top-dying of sundari (Heritiera fomes) trees. In addition to changes caused by the construction of
the Farraka Barrage, the landscapes around the Sundarbans have further been altered by massive
shrimp cultivating operations and the vegetation is vanishing due to high salinity and chemical
fertilizer used in the shrimp farms. The southwestern part of Bangladesh is now a productive shrimp
cultivation zone. Shrimp farming requires that landscapes are modified, resulting in threats to
ecosystems in the coastal region. There are fifty thousand fishermen and local stakeholders that enter
the Sundarbans for fishing and the collection of natural resources on a daily basis.In addition to these developments, construction, urbanization and tourism activities inside the forest
are also helping to change the mangrove landscapes in Sundarbans areas.The Sundarbans mangrove ecosystems are delicate, dynamic and complex and their principal
parameters are the environment, the flora, the fauna and human interference (Choudhury, 1984). The
forest land is highly influenced by tidal interactions because of the presence of these water bodies.
The forest receives freshwater and sediment from a number of distributaries of the Ganges. It hosts
one of the richest natural genepools for forest flora and fauna species in the world, including the
Bengal tiger (Huq, Karim, Assaduzzaman and Mahtab, 1999). Each one of the following elements of
the ecosystem, namely climate, salinity, fresh water, siltation, erosion, substrate and nutrients have
first order reaction on flora and fauna. The upper regions of the Sundarbans are primarily influenced
by the upstream stress conditions. To some extent, the decomposing litter and detritua do affect the
particular tension zone. The factors in the cycles of transported materials include daily tides, run-off,
rainfall, decomposition, mineral intake, and activities of the fauna in general, fish and wildlife in
Int. J. Ecol. Econ. Stat.; Vol. 13, No. W09, Winter 2009 73
particular. A survey of water and soil salinity was conducted at eight sites in the Sundarbans in April
2003.The survey samples were collected from 8 different sites in the Sundarbans region including
Munchiganj, Mirgang, Koramjal, Rupsha River, Kasiabad, Mongla Port, Nilkamal, and Sibsa
Paikgacha location. These findings have shown that in general water and soil salinity in the
Sundarbans increases from north toward the southwest depending on salinity levels of inundating
water. Similarly water salinity increased rapidly and varied from east to west and north to south. The
increasing rate is gradually higher in the dry season (February to June).
The results indicate that until February, water salinity levels were less than 20 ECw
dS/m and a highest density of over 50 ECw dS/m was found in Mirgang, Munchiganj and Nilkamal
points, which are situated in the North West and south middle of the study area. The soil samples
were also collected from the same eight sites and soil salinity levels show trends similar to the
water data .The highest soil salinity levels measured were ECs 41.2 dS/m at Nilkamal, ECs 40 dS/m at Mirgang
and third highest rate of soil salinity is ECs 24 dS/m at Munchiganj point in the northwestern
Sundarbans . The increasing salinity levels are major threats for both biotic and abiotic factors
of mangrove wetland ecosystems in the region. In the Sundarbans mangrove ecosystems, there are
flora that adapt to water-logged areas, breathing by means of outgrowths of roots around the tree.
The best environment for mangroves to flourish is that, there should be adequate fresh water, on the
other hand, all types of mangrove vegetation, trees, shrubs, small plants and chippers are very
sensitive to saline water. Some species flourish in a highly saline environment, while others prefer a
less saline one. The present study focuses on water salinity modelling for up to 13 rivers in the
Sundarbans. After completion of this study, it would be possible to assess the salinity and to estimate
the future negative impacts in the coastal areas. The Fourier polynomial models using a time series
approach would be an important tool for making policies and developing an adequate management
plan for the ecosystems protection in the Sundarbans region.