Md. Arafat Rahman :
World Wetlands Day was celebrated worldwide on Wednesday (February 2) in an annual format. This day is to commemorate the day of signing the conference on wetlands. On this day in 1971, a wetland conference was held in the Iranian city of Ramsar on the shores of the Caspian Sea to highlight the international usefulness of wetlands. The day was first observed worldwide in 1997 and has been considered a bold step since its inception. This day is also celebrated in Bangladesh like other countries of the world.
Wetlands are defined in accordance with the Ramsar Convention, 1971 as “Freshwater, saline or mixed water bodies with natural or man-made, permanent or temporary, stagnant or flowing bodies of water, ponds, ditches or water-rich areas as well as deep marine areas with low tides.” The Ramsar definition of wetlands represents a wide range of freshwater, coastal and marine environments.
The wetlands have a wide range of ecological, socio-cultural, economic and commercial importance and values in Bangladesh. These are important habitats for a large variety of flora and fauna of local, national and regional significance. In the freshwater wetlands the floral composition includes trees, herbs, shrubs and aquatic vegetation. Wetlands are critically important in Bangladesh for human settlements, biodiversity, fisheries, agricultural diversity, navigation and communication, and ecotourism.
More than 5,000 species of flowering plants and 1,500 species of vertebrates, of which approximately 750 are birds and over 500 are coastal estuarine and freshwater fish exist in wetland areas. Some 400 vertebrate species and about 300 plant species are dependent on wetlands for all or part of their life spans. Freshwater capture fishery is an important source of employment in the fishery sector and a supply source of animal protein. About 260 species of freshwater fish exist in wetlands of Bangladesh.
In the last three decades, massive physical infrastructures in the form of rural road and flood embankment have been developed in the wetlands including floodplains and haor areas. Many of these infrastructures disregarded local topographic condition and natural water flow direction, which has often resulted in poor drainage or waterlogging and impacted on the local surface water regime. The critical point of such development activities in the wetlands led the transformation very rapidly at a massive scale.
Human interference in the wetlands has been damaging the fragile ecosystem and sustainability of the wetlands. For instance, in the southwest Bangladesh, farmers used to have a paddy crop only during monsoon season when surface saline layer is depleted due to rainfall and rest of the months in the year, those fields were left for grazing. This cultural practice was established for centuries. However, in the last two decades this practice has been abandoned for more profitable shrimp production. As a result, local ecosystems are threatened because of changed water exchange system, rapid siltation of the channels and continuous inundation of land with saline water.
In the haor areas, largescale settlement was initiated at the mid-20th century from surrounding densely populated regions and since then the resources of the haor basins are being exploited at an increasing rate causing adverse effects. Continuous largescale exploitation of aquatic vegetation and fruits like Makna, Singara, Lotus, Lily, Hogla has caused serious degradation of the quantity and quality of the habitat required for fish and migratory birds of the haor areas. Similarly, embankment constructed for Flood Control Drainage and Irrigation (FCDI) projects reduce floodplains and obstruct fish movement and migration from rivers as well as beels to the remaining floodplains for feeding and breeding. As a result, many fishermen have lost their livelihood.
There have been some positive effects of wetland transformation as well. The major impact has been on cropping patterns and intensity. Dependence on local boro has been shifted towards hybrid boro. In the FCDI project areas, culture fisheries have replaced the deficit of capture fisheries. The positive impact of development projects in the wetlands relates to improved road transport and communication network. This has led to an enhanced marketing infrastructure and relatively easy access to social and other services. Conversely, the navigation system has been either closed or substantially reduced.
As a whole, degradation of wetlands has caused several problems including extinction and reduction of wildlife, extinction of many indigenous wild and domesticated rice varieties, loss of many indigenous aquatic plants, herbs, shrubs and weeds, loss of natural soil nutrients, loss of natural water reservoirs and of their resultant benefits, increase in the occurrence of flooding and degeneration of wetland based ecosystems, occupations, socio-economic institutions and cultures. Wetlands are dynamic ecosystems, which change over a long time. Keeping this in mind, transformation of wetlands through human intervention must be carefully undertaken.
(Arafat Rahman is Asst. Officer, Career & Professional Development Services Department,
Southeast University).
