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.

No abstract

Floristic composition, diversity, dominance and distribution pattern of species and tree population structure were studied in three stands of a sub-tropical wet hill broad-leaved forest of Meghalaya, India, along a disturbance gradient. Tree species diversity declined with increasing disturbance. Disturbed stands showed low equitability or high dominance and the undisturbed stand exhibited high equitability or low dominance. Contagious distribution among the tree species increased with increasing intensity of disturbance. Species showing regular distribution were restricted only to the undisturbed stand. Effect of disturbance on tree population structure was analysed using density-diameter curves. In the disturbed stands tree species showed reverse J-shaped and/or negative exponential curves, while those in the undisturbed stand exhibited sigmoid to bimodal mound shaped curves.

The tribal communities of Meghalaya in northeast India—Khasis, Garos, and Jaintias—have a tradition of environmental conservation based on various religious beliefs which have been passed on from one generation to the other. Based on these beliefs, certain patches of forests are designated as sacred groves under customary law and are protected from any product extraction by the community. Such forests are very rich in biological diversity and harbor many endangered plant species including rare herbs and medicinal plants. Seventy‐nine sacred groves were located, denoted on a geographical map of Meghalaya, and studied for their biodiversity value, status, and vegetation characteristics. A baseline floristic survey revealed that at least 514 species representing 340 genera and 131 families were present in these sacred groves. The status of sacred groves was ascertained through canopy cover estimate. A little over 1.3% of total sacred grove area was undisturbed, 42.1% had relatively dense forest, 26.3% had sparse canopy cover, and 30.3% had open forest. The vegetation characteristics and species diversity of an undisturbed sacred grove were compared with that of an unprotected disturbed forest. The species diversity indices were higher for the sacred grove than for the disturbed forest. The species composition and community characteristics differed significantly between the two forests. Sociocultural aspects of sacred grove conservation were analyzed, and views of the local people were enlisted. Based on the findings, conservation strategies for sacred groves were suggested.

Sacred groves are forest patches conserved by the local people intertwined with their socio-cultural and religious practice. These groves harbour rich biodiversity and play a significant role in the conservation of biodiversity. Population structure and regeneration status of woody species were studied during 2001-2002 in the four sacred groves of Manipur, a state in north east India. A total of 96 woody species was recorded from the four groves, the highest being Konthoujam Lairembi sacred grove (55 species) and lowest in Heingang Marjing sacred grove having 42 species. The density-diameter distribution of woody species in the four groves showed highest stand density and species richness in the lowest girth class (30-60 cm) and decreased in the succeeding girth classes. Overall population structure of the groves based on the number of tree seedlings, saplings and adults, displayed a greater proportion of seedlings followed by saplings and adults while for the selected tree species it varied seasonally and recruitment of species increased during rainy season attaining peak during June. Regeneration status of the four sacred groves based on strength of different age groups in their population showed good regeneration. High occurrence of 'additional species' to the groves may be due to the invasion through dispersal from other areas. Possibly, the prevailing favourable microenvironmental conditions contributed to their establishment and growth in the groves. Absence of seedlings and saplings of some of the species in the groves may be due to their poor seed germination and establishment of seedlings in the forest.