Liana diversity and distribution in four tropical dry evergreen forests on the Coromandel coast of south India

Abstract

Liana diversity was inventoried in four tropical dry evergreen forest sites that are characterized by numerous trees, of short stature and small diameter, and a varying degree of anthropogenic disturbance, on the Coromandel coast of south India. A 1-ha plot was established in each of the four sites and was subdivided into 100 quadrats of 10 m× 10 m. All lianas ≥1 cm diameter at breast height (dbh) rooted within the plot were enumerated. The species richness and density of lianas, with respect to site disturbance and forest stature, varied across the sites. Liana density totaled 3307 individuals (range 497–1163 individuals ha−1) and species richness totaled 39 species (range 24–29 species ha−1) representing 34 genera and 24 families. Combretaceae, Asclepiadaceae, Capparaceae and Vitaceae were the well-represented families. The top five species Strychnos minor, Combretum albidum, Derris ovalifolia, Jasminum angustifolium and Reissantia indica contributed 55% of total density. The slopes of the species–area curves were different for each of the four sites and the curve stabilized in only one site. Of the four climbing modes recognized among the total 39 species, 18 were twiners (56% of the total density). Eight species (24% of density) were tendril climbers and 12 species (16% of density) were scramblers. Hugonia mystax was the only hook climber. All the 39 species and 88% of liana density were encountered within a category of 6 cm dbh or less, and a similar pattern prevailed in the individual sites. Of the three diaspore dispersal modes found among the 39 liana species, animal (64%) and wind (23%) dispersal were predominant over the autochorous mode (13%). Liana diversity and distribution in dry forest communities appear to be influenced by forest stature and site disturbance levels. In the light of the extent of liana diversity and sacred grove status of the study sites, the need for forest conservation, involving local people, is emphasized.