1 Plant Species Diversity and Endemism at Dihang Dibang Biosphere Reserve and its surroundings, Eastern Himalaya Biodiversity Hotspot TARUN P. SINGH tarunsingh@redifmail.com Symbiosis Institute of Geoinformatics 5 th foor, Aturcentre Model Colony, Pune 411016 India SARNAM SINGH sarnam @iirs.gov.in Indian Institute of Remote Sensing 4 Kalidas Road, Dehraun 248001, India Date Submited: June 23, 2011 Final Revision Accepted: August 3, 2011 Abstract - An atempt 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 diferent 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 Art. #81, pp. 1-22 Vol. 3 January 2012 CHED Accredited Research Journal, Category A Print ISSN 2094-1519 • Electronic ISSN 2244-0461 doi: http://dx.doi.org/10.7828/ajob.v3i1.81