On a Dhole Trail: Examining Ecological and Anthropogenic Correlates of Dhole Habitat Occupancy in the Western Ghats of India

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.

Spatio-temporal interactions facilitate large carnivore sympatry across a resource gradient

“…Together, these reserves represent a gradient of densities of ungulate prey as well as carnivores reliably estimated from previously conducted scientific studies (see table 1, [23]; K. U. Karanth 2013, unpublished results). Furthermore, the Malenad landscape in the Western Ghats, within which these four reserves are embedded, also supports larger, viable metapopulations of these three carnivores [25,26]. All four reserves are currently well protected from hunting and other anthropogenic impacts.…”

“…Trap stations, comprising a pair of camera-traps triggered by animal movement, were separated by Euclidean distances of around 1.5 km on average (electronic supplementary material, table S1), and active for 30 consecutive days at each site. We placed camera-traps along forest trails and dirt roads commonly used by all three species as travel routes, to maximize photo-captures [25,26]. Date, time and trap location were recorded for every photo-capture (henceforth, 'encounter').…”

“…Another implication of our study is the possible role of anthropogenic influences [46] on carnivore intra-guild interactions, and, consequently on large mammal communities that they are part of. Such anthropogenic impacts can include land-use changes and economic development increasing the insularity of nature reserves and carnivore communities [25,26,47], human predation on ungulate prey species [48], reduction of wild prey by competing domestic livestock, and modification of habitats through fires or manipulation of vegetation and water resources. On the other hand, exclusive management focus on flagship predators [25] could negatively impact subordinate predator populations [49].…”

Substituting space for time: Empirical evaluation of spatial replication as a surrogate for temporal replication in occupancy modelling

“…Sloth bears are listed as “vulnerable” under the IUCN Red List and under Schedule I of the Indian Wildlife (Protection) Act of 1972. In cases where absolute abundance of animals cannot be estimated from reliable methods, habitat occupancy metrics serve as useful surrogates for understanding their population status (MacKenzie & Nichols, ; Srivathsa, Karanth, Jathanna, Kumar, & Karanth, ; Wong & Linkie, ). We chose the sloth bear as our focal species for three reasons: (1) their indirect signs can be unambiguously identified on field, (2) sampling along forest roads (using either camera traps or sign surveys) usually yields adequate detections, since bears use roads and trails extensively, and (3) their home‐range sizes within resource‐rich habitats are small enough ( c .…”

<b>Distribution and habitat use of the endangered Dhole <I>Cuon alpinus</I> (Pallas, 1811) (Mammalia: Canidae) in Jigme Dorji National Park, western Bhutan</b>

“…Thus, it is one of the least studied and most neglected among the wild carnivores (Srivathsa et al 2014) and there is very little information on Dhole distribution. This information gap is largely attributed to its persistent predation on domestic livestock.…”