A comparative study of the biodiversity of regeneration in the logged and unlogged forest sites in the central Western Ghats, Karnataka, India
Résumé
This study presents a comparative investigation of the biodiversity variation of regeneration in the logged and unlogged sites in the Western Ghats. This research was carried out in selectively logged (37 years before) and unlogged compartments of the low-elevation dipterocarp forest in Uppangala. Individuals with a diameter at breast height from 1 to <10 cm (at 1.3 m) were inventoried in 5 x 5 m sampling plots (25 plots each in 4 logged and 2 unlogged sites). All individuals were tagged and identified to species level. The total regeneration density was 1860 individuals (12.2±5.6 stems in logged and 12.7±7 in unlogged), and species richness was 98 species representing 31 families. Logged sites had higher Shannon and Simpson diversity indices. Five species, namely Humboldtia brunonis, Vateria indica, Knema attenuata, Dipterocarpus indicus, and Psychotria nigra, collectively accounted for 36% of the overall density and exhibited a greater important value index. The size-class distribution of saplings shows an inversed J-shaped curve in both logged and unlogged sites. Approximately 40% of the adult tree species at the logged site and 46% of the unlogged site were not represented in the regenerating species. The occurrence of ten species that are considered rare in unlogged plots was found to be more prevalent in logged sites. These results provide important information for conservation and sustainable forestry management in this ecologically significant area by exposing the response of the forest's flora.