INTERPLAY BETWEEN POLLEN AND VEGETATION IN AND AROUND DHIR BEEL, DHUBRI DISTRICT, ASSAM: A FUTURE POTENTIAL RAMSAR SITE

摘要

Wetland has a significant role to maintain biodiversity offering suitable habitat for support and growth of varied aquatic life forms both macrophytes and microphytes, playing vital role in primary productivity of the ecosystem. This paper deals withthe study of macro and micro phytodiversity in relation to pollen preservation and human impact in and around Dhir Beel of Dhubri District, Assam. The present palynological studies though does not fully match the extant vegetation, the interplay betweenpollen quantum and vegetation in the study area will be of great significance to understand the pattern of pollen / vegetation relationship in a coveted wetland in the District. The presence of Cerealia (Triticum and Oryzd) associated with other culturalpollen especially, Xanthium, Ambrosia, Caryophyllaceae including Paspalum distichum (a typical grass at crop land) directly support pastoral activity in and around the study area. The large number of fungal remains especially Microthyriaceous fruiting body, Xylaria, Nigrospora, Cookenia and Glomus strongly suggest humid climatic condition during deposition of microbiota. The evidence of degraded palynomorphs and few fern allies in sediment suggests the induction of biological degradation in wetland. However, the evidence of degraded pollen like Betula and Corylus also support the long distance transport of microbiota from higher altitude (Arunachal Himalaya). The further study on this exotic element is needed to understand the fact whether the biological degradation happened after incorporation in sediment or carried in degraded form and then become part of sediment.