Aquatic plant community characteristics of some major wetlands of Nalbari district of Assam and resource collection from it by the people of its vicinities

The present study deals with the investigation of the macrophytic diversity of some major wetlands of Nalbari district of Assam, India and their economic prospects. The study was carried out for a period of two years i.e. from January, 2011 to December, 2012. Four wetlands namely Batua kamakhya beel, Borbilla beel, Borali beel and Ghoga beel were selected for the present investigation. While Borali beel and Ghoga beel are regularly affected by river flood water, the other two wetlands i.e. Batua kamakhya beel, Borbilla beel face no such disturbances and are very rich in resources which are utilized by the people living in its vicinities. Various diversity indices of the wetland plant communities were calculated to show the species richness (Margalef, 1964), Shannon – Weiver Diversity Index (Shannon and Weiver, 1963), Simpson’s Dominance Index (Simpson, 1949), Evenness Index (Pielou, 1966) and Similarity index (Sorensen, 1948). During the study period significant values of species richness, diversity and dominance index, evenness and similarity index of the aquatic macrophytes were recorded during the summer season of the study periods. The study shows that the wetlands although situated away from one another yet so far as species contents are concerned, the wetlands have similarities in their plant species composition. These wetlands also act as sources of livelihood and source of bioresources for the people living around its vicinities. During the present study, 141 aquatic macrophytic species belonging to 116 genera and 53 families have been collected and identified from the wetlands of the study sites. Of these 141 species, 55 numbers of aquatic macrophytes which have found to be utilized by the local villagers for different purposes like food (7 sp.), fodder (11 sp.), vegetables (15 sp.), medicine (12 sp.), biofertilizers (9 sp.) and religious functions (8 sp.) for their day to day uses. But unfortunately the population of some economically important macrophytes of the wetlands i.e. Nelumbo nucifera, Trapa natans, T. bispinosa and Euryale ferox are decreasing alarmingly due to excessive anthropogenic pressure as well as natural disturbances in the wetlands occurring over the last few decades. Therefore, proper conservation measure should be taken to conserve these wetlands of the district which are sheltering many important plant species along with other vital resources.