Diversity and Species Composition of Ants (Hymenoptera: Formicidae) in Tropical Forests and Plantations of the Western Ghats

Tropical biodiversity faces a severe threat from the invasion of non-native species. Yet information of habitat that are vulnerable for invasion of potential invasive species is scanty for India, which is particularly true for invertebrates. Ants have some of the most widespread and detrimental invaders globally, but their interaction with habitat and native ants remains obscure. In this paper, we investigated the leaf-litter-ant community to determine and compare ant diversity and the status of ant invasion in various habitats – protected forest, coffee, cardamom, rubber, and tea - of Wayanad Wildlife Sanctuary of the Nilgiri Biosphere Reserve. We used the abundance (proportional trap incidence) of overall ants, native ants, and invasive ants, as well as the richness of overall ants, native ants, and invasive ants as response variables. We found that the richness of overall and native ants, as well as the abundance of overall ants, remained unaffected by land use type. However, the abundance of native ants and Shannon diversity were higher in forests, while the richness and abundance of invasive ants were higher in plantations. Additionally, tropical climate specialist ants were more abundant in forest landscapes. The species composition of forest ants differed from that of plantations. The results suggest that despite both forests and plantations supporting a similar diversity of ants, plantations serve as home for generalists and particularly the notorious invasive ants, while forests maintain a distinct species composition and specialist functional groups.