An attempt has been made to give assessment of plant species diversity of primary and secondary forest vegetation types in Dihang Dibang Biosphere Reserve (DDBR), a single biosphere reserve in Eastern Himalaya. It is excellent example of continuous unbroken forest of the Himalaya from subtropics to mountain tundra while surrounding area of southern part cover tropics. In the present study we have analysed seventy three sample plots in different forest types and species diversity indices were calculated, Shannon-Wiener’s H¢ species richness, evenness, dominant species, dominant verses species richness, and important value index of Biosphere. The species richness in Subtropical evergreen II forest was found highest 7.21 with 350 numbers of species. Owing to the variation of microenvironment, Asian Journal of Biodiversity 2 diversity values within the same vegetation type vary between the samples from different patches. The study would be a great assistance for biodiversity conservation and planning of newly constructed DDBR and its surroundings.
he study would be a great assistance for biodiversity conservation and planning of newly constructed DDBR and its surroundings.