Dominance-diversity; community-coefficient and niche-width relations of woody species in Montane forests of Garhwal Himalaya; India

ABSTRACT

The synthetic characters of different plant communities are analysed. Community-coefficient for tree and shrub layer were 89.99 and 88.49; respectively in North-West aspect of Cedrus deodara forest; probably due to maximum number of species common to both sites. Among the twelve tree species; only two viz.; Cedrus deodara and Cupressus torulosa showed 100 presence amongst all the sites. The maximum equitability (10.47) value was computed in site five; because of similar type of species found in this site. Cedrus deodara (6.34) and Cupressus torulosa (5.54) had broader niches due to their presence at all the sites. Species diversity was highest (3.22) on the North West (NW) aspect of the V site and was directly related to the high density of tree species in this site. Dominance-diversity curve (d-d curve) for the tree layer and shrub layer; based on Importance Value Index (IVI) exhibited a geometric series for all forest sites except site IV; where it reflected Preston's log normal models. The log normal distribution of this site indicated the mixed nature of vegetation. These species are gradually loosing their niche width; density; dominance and diversity in different sites because of over exploitation and over grazing pressure on these species. In view of the great anthropogenic pressure on the plant community; conservation and management measures are required for sustainable use of these important ethnobotanical plant species and plant biodiversity protection