Anthropogenic influences on the tropical evergreen dipterocarp forests of Bangladesh: A phytosociological perspective

Like other developing countries, the tropical evergreen forests of Bangladesh are experiencing increasing human pressure. A study has been conducted over the last eleven years (1995-2005) to identify the types and magnitudes of anthropogenic disturbances and its impact on natural forests. 'Indirect observation method' was used for identification of the modality and magnitude of anthropogenic disturbances. Impact on the forest composition were studied through line transects and list quadrats method in a combination of random and purposive sampling. Along with indirect observation, the results obtained from transect and quadrats were compared with the undisturbed forest. Four broad categories of anthropogenic disturbances viz. illicit felling of trees for timber, pole and fuel wood, clearing of forest areas for habitation, conversion of forest land to for agriculture and grazing of cattle. The magnitudes of disturbances are also increasing with time. Based on the existing data, the future disturbance regimes have been forecasted. Changes in the forest composition were found conspicuous in terms of stratification, species composition, tree density, basal area, diversity and dominance. Management system with particular emphasis on participatory management, conservation of biodiversity and continuous community based monitoring is recommended to minimize the anthropogenic disturbances and restoring the disturbed natural forests.