Effects of anthropogenic disturbance on plant diversity and community structure of a sacred grove in Meghalaya, northeast India

Abstract

This study analyses the effects of anthropogenic disturbance on plant diversity and community attributes of a sacred grove (montane subtropical forest) at Swer in the East Khasi Hills district of Meghalaya in northeast India. The undisturbed, moderately disturbed and highly disturbed stands were identified within the sacred grove on the basis of canopy cover, light interception and tree (cbh $ 15 cm) density. The undisturbed forest stand had .40% canopy cover, .50% light interception and a density of 2103 trees per hectare, whereas the highly disturbed stand had ,10% canopy cover, ,10% light interception and 852 trees per hectare. The moderately disturbed stand occupied the intermediate position with respect to these parameters. The study revealed that the mild disturbance favoured species richness, but with increased degree of disturbance, as was the case in the highly disturbed stand, the species richness markedly decreased. The number of families of angiosperms was highest (63) in the undisturbed stand, followed by the moderately (60) and highly disturbed (46) stands. The families Rubiaceae, Asteraceae and Poaceae were the dominant families in the sacred forest. Rubiaceae was represented by 11, 14 and 10 species in the undisturbed, moderately disturbed and highly disturbed stands, respectively, whilst the family Asteraceae had 16 species in the moderately disturbed stand and 14 species in the highly disturbed stand. The number of families represented by a single species was reduced significantly from 33 in the undisturbed stand to 23 in the moderately and 21 in the highly disturbed stand. The similarity index was maximum (71%) between the undisturbed and moderately disturbed stand and minimum (33%) between the undisturbed and highly disturbed stands. The Margalef index, Shannon diversity index and evenness index exhibited a similar trend, with highest values in the moderately disturbed stand. In contrast, the Simpson dominance index was highest in the highly disturbed stand. There was a sharp 21 2 21 decline in tree density and basal area from the undisturbed (2103 trees ha and 26.9 m ha ) to the 21 2 21 moderately disturbed (1268 trees ha and 18.6 m ha ) and finally to the highly disturbed (852 trees 21 2 21ha and 7.1 m ha ) stand. Density-girth curves depicted a successive reduction in number of trees in higher girth classes from the undisturbed to the moderately and highly disturbed stands. The log-normal dominance-distribution curve in the undisturbed and moderately disturbed stands indicated the complex and stable nature of the community. However, the short-hooked curve obtained for the highly disturbed stand denoted its simple and unstable nature.

Community Structure and Plant Diversity of Community Based Religious Conserved Forests of Garhwal Himalaya, India

“…Simpson's index observed for herb layer was within the range of 0.06 to 0.09. Shannon Index diversity (Hʹ) and concentration of dominance (CD) were found inversely proportional to each other which have also been suggested by Misra et al [51]. The values of present study for (CD) fall within the reported values of Whittaker and Niering [52] and Risser and Rice [53] for temperate vegetation (0.01-0.99) [54].…”

“…The values are more or less similar to reported values of (0.55 to 0.83), (0.93 to 0.99) and (0.92 to 0.96) for trees, shrubs and herbs in four sacred groves of Manipur. The values of present study are little more than reported value (0.4) for a sacred grove in Meghalaya north-east India [51].…”

“…Regular distribution pattern was entirely absent. Mishra and Laloo [46] and Upadhaya et al [47] also reported contagious pattern of distribution for sub-tropical forests of north-east India. Other studies conducted within Garhwal Himalaya [48,49] Table 2: Different ecological and diversity parameters across study sites.…”

Ethnomedicinal Plants of India with Special Reference to an Indo-Burma Hotspot Region: An overview

“…Sacred groves of NE India are a reservoir of medicinal plants (Laloo et al 2006, Mishra et al 2004. The indigenous tribes have protected the groves since time immemorial due to their various religious beliefs attached to them.…”

Comparison of plant species diversity with different plant communities in deciduous forests

“…Plant communities are separated from each other based on indicator species in combination with a distinctive floristic composition. The latter is considered as one of the major distinguishing characters of a community (Dansereau, 1960) and therefore, any depletion of biodiversity is bound to alter the community attributes (Mishra et al, 2004).…”