Tree species diversity and population structure across major forest formations and disturbance categories in Little Andaman Island, India

The Andaman and Nicobar islands, located in the Indian ocean, are among the biodiversity rich localities in India. Several islands in the southern part were severely affected by a recent cyclone 'tsunami. We compared patterns of tree species diversity and extent of damage by tsunami at eight sites in Little Andaman island within eight one ha plots. The study sites were located at relatively undisturbed and disturbed Evergreen (UE, DE), Semi-evergreen (US, DS), Deciduous (UD, DD) and Littoral (UL, DL) forests. A total of 4252 trees .30 cm girth at breast height, covering 186 species in 125 genera and 56 families were recorded within these sites. Of these, 23 species (12.4%) were endemic to these islands. Tree species richness was lowest (18 species ha super(-1)) in the tsunami affected littoral forest and highest (84 species ha super(-1)) in the UE. Tree density (79 to 935 trees ha super(-1)) and basal area (41 to 59.10 m super(2) ha super(-1)) were greater in all the undisturbed forests as compared to disturbed forests. In all the eight sites, tree species richness and density decreased with increasing girth class and the stand structure of the forests displayed a reverse J-shaped curve, with the exception of the DL. Importance Value Index of three endemic species viz., Manilkara littoralis, Canarium euphyllum and Terminalia bialata has been compared across the forest types and tsunami hit areas. Management implications are discussed.