Species diversity, community characteristic and population structure in disturbed and undisturbed forest of sepahijala wildlife sanctuary, Tripura

This study was conducted in Sepahijala Wildlife Sanctuary, West Tripura, India to assess the plant diversity, community characteristics and population structure in buffer and core areas using random sampling procedures. Altogether 74 woody species were recorded from selected forests and revealed that species diversity and density increases with decrease in disturbance. Other community parameters such as basal cover and indices did not showed much variation among the stands. Forest canopy was composed mainly of Shorea robusta, Schima wallichii, Aporosa dioica. Majority (84% to 88%) of species showed low frequency making community heterogeneous. Basal cover was slightly higher (39.82 m2 ha-1) in disturbed forest than the undisturbed forest (37.54 m2 ha-1) in spite of low stand density. Greater proportion of contagiously distributed species made the community highly patchy in nature. Similarity between the stands was high mainly due to being part of same land cover. Diversity indices for woody species was higher in undisturbed forest than the disturbed forest areas, however, dominance index reveals the reverse trend to that of woody species. The overall population density of seedlings, saplings and adult trees formed a pyramidal structure indicated that the period between saplings to adult stage was critical stage in the life cycle, as the maximum mortality occurred during this period. Based on the results of the above study it can be concluded that forest degradation leads to reduction of forest areas, isolation of smaller patches, habitat loss and increased ground growth. Grazing and other anthropogenic activities in the forest areas should be restricted by the authority to check further degradation in the wildlife sanctuary.