Understory Plant Diversity in Tropical Dry Evergreen Forests on the Coromandel Coast of India Under Various Disturbance Regimes

Abstract

Tropical forest vegetation and community research have largely tended to focus on the tree component, and limited attention has been paid to understory vegetation. Species richness and density of understory plants were studied in disturbed and undisturbed sites of tropical dry evergreen forests on the Coromandel Coast of India. A total of 400 quadrats distributed hundred each in four forest categories and ten replicate sites of each of them. We found 4870 individuals of understory plants belonging to 59 species, 51 genera and 24 families. Across the four forest disturbance categories, the species richness ranged from 14 to 43 species. The HD sites harbored greater number of species and density than other forest categories. Herbs dominated by species and density than the other habit types. Acanthaceae, Euphorbiaceae and Papilionaceae constituted the species-rich families represented by 6 species each. The abundance and species richness of invasive species strongly correlated with disturbance scores (R2= 0.977; R2= 0.94). The invasive species richness was highest in the HD sites (17 species) and least in RD sites). The present study indicates the increasing invasion in disturbed sites and hence undisturbed sites call for conservation efforts and the disturbed sites warrant eco-restoration by way of better protection to save the native biodiversity of this understudied forest type.