Changing dynamics of river ecosystem from aquatic to terrestrial: A case of Bhairab River, Jashore, Bangladesh

Abstract

The changing dynamics of river ecosystems from aquatic to terrestrial in the Southwestern areas of Bangladesh have been widely observed in recent years. Nevertheless, there has been no consensus on whether the changes are caused by human activities or by natural processes. For a better understanding of the cause, this study was conducted based on a field survey through a pre-tested structured questionnaire measuring the river water quality. The water quality of the river was assessed to know how much the existing river water was affecting its aquatic ecosystem or not. People’s perception was also investigated to assess the factors mostly responsible for changing the river ecosystem. It was found that the most responsible factors are human activities. Among them, the construction of cross embankments over and along the Bhairab River was the most (22%) responsible factor for changing the river ecosystem. The 2nd and 3rd most responsible factors were bridge construction (18%) and illegal encroachment (18%). Other reasons for changing the ecosystem of the river were the diversion (16%), cultivation of the riverside land (12%), the introduction of exotic species (8%), and disposal of wastes and industrial effluents into the river (6%), respectively. Besides, it is also believed that the construction of Farakka Barrage on the River Ganges (the mother of the Bhairab River) is also responsible for changing the aquatic ecosystem into a terrestrial ecosystem.