Dry season resource selection among sympatric ungulates in a tropical coastal landscape: implications for conservation and management

Abstract

Differential resource use by sympatric species mediates coexistence by specialising in individual ecological niches. We investigated the population, habitat use and dietary overlaps between wild ungulates, i.e., blackbuck Antilope cervicapra, chital Axis axis, domestic livestock and feral horse at Point Calimere Wildlife Sanctuary, India. The food habits and diet overlap of ungulates were estimated using the feeding site method and the density were estimated using distance sampling-based line transect approach. The estimated overall density (number of individuals per km2 ± SE) of blackbuck was (37.1 ± 5.2), chital (4.5 ± 0.9), feral horse (7.6 ± 1.2) and cattle (21.9 ± 3.3). The target species fed on 43 plant species, of which, plant use was high in feral horse (35), followed by chital (33), cattle (29) and blackbuck (23). Dung/pellet analysis revealed that all the target species used monocots (graminoids) in high proportion. Feral horse had the highest habitat niche breadth (0.89) followed by cattle (0.72), blackbuck (0.48) and chital (0.26). Diet overlap was maximum between blackbuck and cattle (95%) followed by feral horse (81%), and chital (38%) with respect to blackbuck. The observed high degree of diet overlaps between wild ungulates with domestic livestock and feral horses is a matter of concern for the long-term survival of the wild ungulates.