Influence of disturbance regime on liana species composition density and basal area in the tropical montane evergreen forests (sholas) of the Western Ghats India
Mohandass D; Davidar P; Somasundaram S; Vijayan L; Beng KC
Lianas have been shown to respond to natural and anthropogenic disturbances\r\nin many tropical forests worldwide. However little is known about how disturbance affects liana composition density and basal area in the tropical montane evergreen forests (sholas) of the Western Ghats India. We used a large dataset from permanent monitoring plots across four sites to examine whether liana composition stem density and basal area were influenced by moderate level disturbance. Vegetation data were collected from four sampling sites that cover\r\n13.58 ha in the southern montane evergreen forests (sholas) of the Western Ghats. All liana individuals with diameter at breast height (dbh) =1 cm were tagged counted mapped and identified to species level. A total of 1658 individuals belonging to 18 families 24 genera and 33 species were recorded. Species richness did not differ significantly between disturbed and undisturbed sholas in Amaggal (AG) Kukkal (KK) and Upper Bhavani (UB) sites but it differed significantly in Korakundah (KR) site (P < 0.05). Species composition of lianas responded to disturbance at lower percentage (9 %) among four sites. Density of lianas was\r\nsignificantly higher in disturbed than in undisturbed sholas across all four sites. Mean densities were 10.19 ± 6.10 and 5.69 ± 3.35 in disturbed and undisturbed sholas respectively while the proportions of stem densities were 66 % and 34 % in disturbed and undisturbed sholas respectively. Surprisingly basal area showed contrasting trends in disturbed and undisturbed sholas. In KR and UB sites mean basal area was significantly higher in undisturbed than in disturbed sholas while in AG and KK sites mean basal area was significantly higher in disturbed than undisturbed sholas. The findings of the study indicate that moderate level human disturbance influenced liana composition abundance and basal area within the studied region.