Abstract
Although they play a critical role in shaping ecological communities, many threatened predator species are data-deficient. The Dhole Cuon alpinus is one such rare canid with a global population thought to be <2500 wild individuals. We assessed habitat occupancy patterns of dholes in the Western Ghats of Karnataka, India, to understand ecological and anthropogenic determinants of their distribution and habitat-use. We conducted spatially replicated detection/non-detection surveys of dhole signs along forest trails at two appropriate scales: the entire landscape and a single wildlife reserve. Landscape-scale habitat occupancy was assessed across 38,728 km2 surveying 206 grid cells of 188-km2 each. Finer scale habitat-use within 935 km2 Bandipur Reserve was studied surveying 92 grid cells of 13-km2 km each. We analyzed the resulting data of dhole signs using likelihood-based habitat occupancy models. The models explicitly addressed the problematic issue of imperfect detection of dhole signs during field surveys as well as potential spatial auto-correlation between sign detections made on adjacent trail segments. We show that traditional ‘presence versus absence’ analyses underestimated dhole habitat occupancy by 60% or 8682 km2 [naïve = 0.27; (SE) = 0.68 (0.08)] in the landscape. Addressing imperfect sign detections by estimating detection probabilities [ (L) (SE) = 0.12 (0.11)] was critical for reliable estimation. Similar underestimation occurred while estimating habitat-use probability at reserve-scale [naïve = 0.39; (SE) = 0.71 (0.06)]. At landscape scale, relative abundance of principal ungulate prey primarily influenced dhole habitat occupancy. Habitat-use within a reserve, however, was predominantly and negatively influenced by anthropogenic disturbance. Our results are the first rigorous assessment of dhole occupancy at multiple spatial scales with potential conservation value. The approach used in this study has potential utility for cost-effectively assessing spatial distribution and habitat-use in other species, landscapes and reserves.
Highlights
Large carnivores are highly threatened across the world [1] and populations face risks of local extinction because they are wideranging and occur at relatively low densities [2,3,4]
In India, dholes were considered vermin and bounty-hunted to the verge of extinction before they received legal protection in 1972 [14,15]. They have been extirpated from 60% of their former range in the last century due to human persecution and loss of forest cover, and occur primarily in protected wildlife reserves embedded within larger multiple-use landscapes [16,17]
Occupancy models to address spatial auto-correlation When estimating occupancy at both landscape and reserve scales, we first compared the standard MacKenzie et al [28] model with the Hines et al [54] model that explicitly addresses the likely spatial auto-correlation of sign detections made along spatial replicates
Summary
Large carnivores are highly threatened across the world [1] and populations face risks of local extinction because they are wideranging and occur at relatively low densities [2,3,4]. A full understanding of large-scale carnivore distribution as well as patterns of habitat-use within wildlife reserves can be gained only by identifying ecological and anthropogenic factors that are key determinants of habitat occupancy. In India, dholes were considered vermin and bounty-hunted to the verge of extinction before they received legal protection in 1972 [14,15]. They have been extirpated from 60% of their former range in the last century due to human persecution and loss of forest cover, and occur primarily in protected wildlife reserves embedded within larger multiple-use landscapes [16,17]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
