Assessing landscape-scale determinants of Dhole Cuon alpinus occurrence in the Western Ghats of Karnataka, India.
Centre For Wildlife Studies, BangaloreAuthors
Arjun Srivathsa, Devcharan Jathanna, N Samba Kumar, K Ullas Karanth
There is a lack of baseline data on distribution and population status of most carnivores in India because of their rarity and elusiveness. Studies on determinants of occurrence are therefore important in conserving these species. The endangered Dhole is one such carnivore that largely inhabits forests of India. We assessed habitat occupancy of dholes in the Western Ghats of Karnataka and explored ecological and anthropogenic factors driving dhole occurrence.
We carried out spatially replicated sign surveys along trails and roads in forested areas. Indirect signs like tracks and scats of dholes were recorded in each kilometer-long replicate. A total area of 38,700 km2 was surveyed between 2006-2008. A grid overlay (206 188km2-grids) was superimposed on the area to estimate dhole occupancy. We used likelihood-based occupancy models that accounted for both imperfect detection and non-independence of spatial replicates.
A presence-versus-absence approach estimated dhole occupancy in Western Ghats at 27%. When corrected with accounting for imperfect detection and Markovian dependence of spatially contiguous replicates, it was estimated that dholes occupied about 60% of the landscape. Our results show that presence of principal prey species and anthropogenic disturbance are important factors influencing spatial distribution of dholes.
Our study represents the first attempt at a landscape-scale assessment of dhole distribution in India using robust occupancy models. Conservation initiatives for dholes are severely hindered by the dearth of quantitative studies on their ecology. While addressing the key issue of imperfect detection in distribution surveys, our results also point at the pertinence of understanding ecological processes driving distribution patterns for an endangered carnivore