SPECIES DIVERSITY AND COMMUNITY PATTERNS ALONG THE DISTURBANCE GRADIENT IN DRY TROPICAL FORESTS OF CHITRAKOOT, BANDA (U.P.) INDIA

Abstract

The magnitude and recurrence of disturbance is the main factor to affect the structure of the forest communities in a variety of ways. A forty KM long disturbance gradient was identified across the forest of Chitrakoot in Banda Forest Division and the impact of different degrees of disturbance on the community attributes and diversity pattern of the forests along this gradient, was observed. The sum of frequency for species components of different stands increased along the gradient with marked fluctuations. The sum of density, however, increased only upto a few peripheral stands and stabilized further. The trend of the two indices and fluctuations in these values indicated highly patchy and heterogeneous communities along the disturbance gradient. Several potential under trees like Mallotus and Clerodendron dominated the shrub layer with greater abundance under high disturbance while other non-leguminous species of shrubby habit dominated the stands facing intermediate disturbance. The relative density of leguminous shrubs decreased along the gradient. The efficiently sprouting trees like Holarrhena and Terminalia have maximum importance value index (IVI) at moderate disturbance while Scleichera oleosa did so toward the core. A maximum Shannon’s Index of Diversity H of 3.53 was observed for the last but one stand towards the core. The trends of dominance and β-diversity were reverse to that of α-diversity along the gradient. From these observations, it may be inferred that the disturbance should be contained at the level suited for maximum diversity beside sparing a few ‘disturbancefriendly’ species in highly disturbed stands from complete destruction in order to provide bare minimum herbage cover, required for ecosystem attributes for the forests of the region.