At present the biodiversity of the riparian forest is under threat due to various anthropogenic pressures. Hence study was conducted along the three unprotected zones of riparian forest in Dikhu river, Nagaland, north-east India in order to compared the diversity, distribution and population structure of riparian trees. In each zone 100×100 m2 plot were marked and subdivided into 20 plots of 10×10 m2. 10 plots on each side of the river were taken randomly covering 0.02 ha. Only tree with dbh ≥10 cm and dbh above 1.5 m above ground level were recorded as individual species. A total of 29 tree species belonging to 18 families were recorded from the three zones of the river. Tree species richness was highest at the middle zone (19) followed by upper (14) and lower zone (7). The most abundant species and family recorded at upper, middle and lower zones were Melia azaderach of Euphorbiaceae (380 stems ha-1), Terminalia chebula of Euphorbiaceae (432.5 stems ha-1) and Duabanga grandiflora of Lythraceae (365 stems ha-1) respectively. The ranges of diversity indices observed in the three zones were: Shannon-Wiener index (1.25-0.73), Simpson diversity index (0.42-0.93), Evenness index (0.47-0.37) and Index of co-dominance (0.75-0.94). Rest of other indices were also estimated and compared. Distribution of trees shows the contagious pattern common in the upper and middle zones and regular in the lower zone. The girth size class analysis demonstrated that the riparian forest is in less mature succession stage. This study emphasize the need for management and conservation of riparian forest by developing policy to declare the riparian zone as protected area to prevent further degradation and loss of biodiversity from these unregulated zones along the river.
목차
Abstract Introduction Materials and Methods Study areas Vegetation analysis and identification of Species Data Analysis Measurement of biodiversity indices Results and Discussion Species composition and distribution of trees Distribution pattern Population structure Diversity indices and their measures Conclusion Acknowledgements References
키워드
riparian treesunprotected zonetropical forestEastern HimalayaDikhu river
저자
Devlin Leishangthem [ Centre for Biodiversity Studies, Department of Botany, Nagaland University, Lumami-798627, Nagaland, India ]
Maibam Romeo Singh [ Centre for Biodiversity Studies, Department of Botany, Nagaland University, Lumami-798627, Nagaland, India ]
Corresponding author