Plant diversity and forest structure of the three protected areas (Wildlife Sanctuaries) of Bangladesh sundarbans: Current status and management strategies

Abstract

The protected areas of Sundarbans maintain a globally significant ecosystem and provide ideal habitats for aquatic resources (fish, shrimp), birds, and wildlife. The UNESCO World Heritage Committee declared the whole Sundarbans as its 798th heritage site including three wildlife sanctuaries in order to conserve all flora and fauna. The study area, covering an area of 139,700 ha, was surveyed in the year 2012-2013 by stratified systematic sampling. The sampling sites were previously stratified on the vegetation map depending on the available forest types. A total of 31 families with 63 species and 11,619 individuals were enumerated from the study site across all size classes of trees including non tree plants. Leguminosae was found to be a comparatively diverse family having ten species, and Euphorbiaceae was dominated by a large number of individuals. The plant species richness (herbs, shrubs, climbers, etc.) was predominantly confined to the streamside than the 'forest proper', and the mean of these two groups was statistically significant. Due to domination by a few species, the overall Shannon's value of the study area was only 2.19. Mean number of species significantly varied between the protected areas. Species accumulation curves did not follow regular fashion due to domination by few species. The cluster diagram has validated environmental factors to discriminate species composition in protected areas. All other stand parameters also varied. Results are compared with the few available studies. Management of the study area should incorporate research activities to determine successional change due to dynamic ecological process.