Mangrove wetland ecosystems in Ganges-Brahmaputra delta in Bangladesh

Abstract

The Sundarbans is one of the productive mangrove wetland ecosystems in the Ganges-Brahmaputra delta in Bangladesh. The delta is undergoing rapid ecological changes due to human activity. In the present study, surface water salinity data from 13 rivers of the Sundarbans were collected in order to investigate the saline water intrusion in the mangrove wetlands. Results demonstrate that saline water has penetrated the upstream area as river water salinity has increased significantly in 1976 compared to the year 1968. The soil and river water salinity data also shows that it has crossed the water salinity threshold line in most parts of the Sundarbans wetlands. These observations are due to the construction of Farakka Barrage in 1975, which reduced the water discharge of the Ganges River from 3700 m 3 /s in 1962 to 364 m 3 /s in 2006. The shortage of freshwater discharge to the deltaic area is trailing active ecosystems function, especially in the dry season in the south western region in Bangladesh. The objective of this study is to understand and analyze the present degraded mangrove wetland ecosystems and their negative impacts. The findings of this study would contribute to the formulation of the mangrove wetland ecosystems management plan in the Ganges delta of Bangladesh.

Climate Variability and Mangrove Cover Dynamics at Species Level in the Sundarbans, Bangladesh

“…The relationship between the dynamics of H. fomes, S. apelatala and C. decandra, and change in rainfall pattern support Field (1995) and Ellison (2000) who argued that rainfall patterns affect spatial distribution of mangrove species. This may also be related to higher supply of sediment, lower exposure to sulphates, increased salinity [5,6,11,15,45] and reduced discharge of freshwater flows from the upper stream [46]. In the present study, the decreasing trend of H. fomes and increasing trend of C. decandra support the suggestion that decreased rainfall and resulting higher salinity may be a factor that contributes to the observed change.…”

Differential livelihood adaptation to social-ecological change in coastal Bangladesh

“…Intrusion of saline water from the Bay of Bengal poses significant challenges in the dry season when lack of rainfall decrease upstream river flows. This seasonal phenomenon has been exacerbated by the withdrawal of water at the Farakka dam in India and the construction of hundreds of coastal 'polders' (embanked islands) in Bangladesh during the 1960s-70s (Islam and Gnauck 2008). Construction of these polders was part of the 'green revolution' that sought to intensify crop production and increase food security by protecting agricultural land from tidal floods and salinity intrusion (Islam and Kibria 2006).…”

Blue Carbon Stock of the Bangladesh Sundarban Mangroves: What could Be the Scenario after a Century?

“…It has been long recognized by earlier workers that the species distribution or zonation of mangroves are dependent on several controlling factors (Tomlinson 1986;Naskar and Guha Bakshi 1987;Chaudhuri and Choudhury 1994), out of which, salinity profile is one of the most crucial factors (Ellison et al 2000;Bhattacharjee et al 2013). The western part of the Sundarban is mainly influenced by high salinity waters (Banerjee et al 2012), whereas on the eastern side of the Sundarban (especially on the eastern end of the Bangladesh Sundarban) a lower salinity region is known to exist (Islam and Gnauck 2008). The region lying in has a moderate salinity range (Karim 1988).…”