| الوصف: |
Undergrowth species diversity was investigated by random quadrat method. Ordination and Shannon-Wiener diversity index were produced by the CANOCO program and Cluster analysis was done by the SAS (Statistical Analylitical System, sixth version) program. 48 undergrowth species were recorded in the Sundarban mangrove forest belonging to the dominant families such as Fabaceae (Cynometra ramiflora, Dalbergia spinosa, Derris trifoliata), Poaceae (Myriostachya wightiana, Porteresia coarctata), Palmae (Nypa fruticans, Phoenix paludosa), Acanthaceae (Acanthus ilicifolius), Pteridaceae (Acrostichum aureum), Myrsinaceae (Aegiceras corniculatum), Rhizophoraceae (Rhizophora mucronata, Bruguiera gymnorrhiza). On the basis of frequency distribution of undergrowth vegetation data sets six undergrowth species were found to be dominant and widely adapted to the various salinity conditions in different zones of Sundarban mangrove forest, which were frequently occurring in most of the sites and quadrats such as Acanthus ilicifolius, Acrostichum aureum, Derris trifoliata, Vitis trifoliata, Sarcolobus globosus and Phoenix paludosa. The Sundarban forest, located in the southwest of Bangladesh, is one of the largest continuous blocks of mangrove forests in the world. This mangrove forest ecosystem in Bangladesh is now in captious position. Negative natural and anthropogenic impacts and overexploitation of natural resources have caused severe damage to the ecosystem. Growing human population with few alternative livelihood opportunities poses a serious threat to the mangrove forest. The rapidly expanding shrimp farming industry is a significant threat to the mangrove forests of Bangladesh. Due to illegal cutting, encroachment of forest areas and illegal poaching of wildlife, the mangrove forest is losing biodiversity in an alarming rate. This forest ecosystem also has become vulnerable to.pollution, which may have changed the ecosystem's biogeochemistry. Further threats arise from global climate change, especially sea level rise. This ... |
