Assessment of Floristic Diversity of Mangrove Vegetation in Bagagahan Heronry of the Bhitarkanika National Park, Odisha, India

3 Abstract: The study describes the species assessment of species diversity of the plant community of Bagagahan Heronry in the Bhitarkanika National Park, Odisha. Specific attention was made on all the mangrove species of the study area based on flora data obtained during December 2013 and January in 2014 after the herons nesting process was over. A total of 10 plant species belonging to 9 families were recorded from the study site, of which 4 and 10 species of mangroves from the core zone and the non-core zone of the Bagagahan Heronry respectively. At the core of the Bagagahan Heronry their highest importance value index (IVI) (237.92) was recorded for Excoecaria agallocha and in the non-core there the highest IVI was also recorded for Excoecaria agallocha (153.08) and least IVI was recorded for Hibiscus tiliaceus (4.37) in the core zone and Salacia prinoides (2.47) in the outer non-core zone. In sapling stage there Excoecaria agallocha has the maximum IVI in the core zone (288.57) and the same has maximum IVI in non-core zone (276.83) too, whereas least IVI was recorded for Cynometra europa (11.42) in core zone and Heritiera fomes (23.16) in the non - core zone. In seedling stage there higher seedling density is found in the non - core zone than core zone. In seedling stage there Excoecaria agallocha has the maximum IVI in core zone (219.35) and in non-core zone (240.79) and least IVI in core zone is recorded for Cynometra iripa and Hibiscus tiliaceus (3.373) in core zone and for Cynometra iripa, Ceriops decandra and Xylocarpus granatum (3.77). The highest dominance (D = Simpson Index of Dominance) was recorded for sapling (1) followed by trees (0.83) and seedlings (0.747) in the core of the Bagagahan Heronry. Whereas in the non - core zone of the heronry the highest dominance is recorded in sapling (0.992) followed by seedling (0.951) and trees (0.82). The species diversity (H = Shanon Diversity Index) was recorded highest for seedling (0.458) followed by trees (0.378) and saplings (0.014) in the core zone of the heronry and in the non - core zone of the heronry the species diversity is highest for trees (0.949) and lowest for saplings (0.028). The core zone of the heronry is surrounded by non-core zone of the heronry having more stable plant community compare to the core zone of the Bagagahan heronry.