M Sc Dissertation(WII)

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Droppings and densities: can sprainting intensity predict otter abundance
(Wildlife Institute of India, Dehradun, 2026) Balaji, Pritham; Pandav, Bivash; Kher, Varun
Reliable estimates of population abundance are fundamental to understand population dynamics and inform conservation management. However, obtaining robust abundance estimates for rare and elusive species remains challenging because rigorous population estimation methods are often not feasible on large scales, require long survey periods, resources and technical expertise. Consequently, wildlife monitoring efforts frequently rely on population indices derived from indirect evidence of the species of interest or proportion of sites occupied. Although the relationship between these indices and population abundance is seldom evaluated. This uncertainty is particularly relevant for otters, which have primarily been studied using their indirect signs which were developed to monitor population status. Smooth-coated otters (Lutrogale perspicillata), a semi-aquatic carnivore for which ecological studies have traditionally relied on indirect signs to study their habitat and diet preferences. Despite its threatened status, there is very little quantitative information on population sizes and trends. This study aimed to estimate the population status of smooth-coated otters inhabiting three Himalayan foothill rivers using multiple complementary approaches and to evaluate whether spraint encounter rates could provide a reliable indication of relative abundance. Camera trap distance sampling, N-mixture modelling based on direct sightings were used to estimate otter populations in each river. Sign surveys were conducted to obtain relative abundance indices such as encounter rates or occupancy probability from each river. By incorporating the use of camera traps, insights into their activity pattern was analysed in these rivers which are outside a protected area that vary in levels of anthropogenic disturbance. The N-mixture model produced highly uncertain abundance estimates because of low detection probability and high variability in count data, indicating that direct-sighting approaches are unlikely to provide reliable abundance estimates for smooth-coated otters under similar field conditions. Camera trap distance sampling generated substantially larger datasets and yielded more precise estimates of detection probability and density, demonstrating greater potential for estimating otter populations. Nevertheless, the number of detections remained insufficient to estimate abundance independently for each river, highlighting the need for increased sampling effort and more rigorous approaches, such as non-invasive genetic approaches or telemetry information, to obtain robust population estimates. Single-season occupancy modelling was of limited value for comparing relative abundance because otters occupied nearly all sampling units within the study area, providing no variation in occupancy estimates between rivers. Similarly, indirect sign surveys for spraint sites failed to show a significant relationship with camera trap encounter rates or estimated population status. Although Khoh exhibited substantially higher camera trap encounter rates than Kolhu, spraint encounter rates showed the opposite pattern, suggesting that sprainting intensity alone is not a reliable proxy for smooth-coated otter abundance in these river systems. These findings support evidence that social behaviour, communal latrine use and habitat-specific detectability can weaken the relationship between spraint site encounter rates and population size. Activity pattern analyses revealed that smooth-coated otters were primarily diurnal and crepuscular. However, otters in the more disturbed Khoh River exhibited a pronounced shift towards crepuscular and nocturnal activity compared with those in Kolhu. This demonstrates the behavioural adaptability of smooth-coated otters to human disturbance in their habitat. Therefore, this study provides one of the first quantitative assessments of smooth-coated otter populations using multiple abundance estimation frameworks in the Himalayan foothills. Although constrained by sample size and limited to two rivers, the study establishes important baseline estimates and demonstrates both the potential and limitations of current monitoring approaches which have been used for other taxa. The findings suggest that camera trap distance sampling currently represents the most promising non-invasive method for estimating smooth-coated otter populations, whereas spraint encounter rates should be interpreted cautiously and not used as a standalone indicator of abundance. Future studies incorporating larger spatial scales, increased sampling effort and rigorous abundance estimation methods will be essential for validating these findings and improving conservation monitoring of this threatened freshwater carnivore.
Assessing the distribution and density of the Fishing Cat in Bhitarkanika mangroves of eastern India by
(Wildlife Institute of India, Dehradun, 2024) Ashik, C.S.; Mukherjee, Shomita; Gopi, G.V.; Pandav, Bivash
Identifying the areas of occurrence, population, and the factors affecting the species distribution is critical in conservation and management. The Fishing Cat (Prionailurus viverrinus), a smaller feline native to South and Southeast Asia, is globally vulnerable and adapted to wetland habitats, with a diet primarily consisting of fish. This makes Bhitarkanika, a mangrove ecosystem, an ideal habitat for the Fishing Cat. This study was conducted to estimate the species density, determine the factors affecting its distribution, and assess the effect of lunar illumination and tidal fluctuation on Fishing Cat activity. Despite known occurrences of Fishing Cats in this area, there has been no proper assessment of their population or other ecological studies. Camera traps were deployed in 109 grids, each covering 1km², across a total of 145 km², for 2878 trap nights. Camera trap locations are unbaited, with two cameras used to capture both flanks. Spatially explicit capture-recapture (SECR) was used to estimate the density, resulting in 0.6 ± 0.1 individuals per km². The abundance was also calculated, with an estimate of 99 ± 16 individuals. These density estimates from this study are close to recent high-density estimates for the species. The canopy cover, the width of the creek, canopy cover and the distance to the aquaculture farms significantly influenced the Fishing Cat habitat use, indicating the need for the conservation of natural mangrove habitats and regulation of aquafarms present near the forest. In contrast, the presence of Saltwater Crocodile showed a negative effect on the distribution of Fishing Cats. The Fishing Cats were more active during the brighter nights of the moon phase (μ= 266.783, r= 0.051, p< 0.01) due to better visual detection. The activity was influenced both by the tidal fluctuations in terms of food resources from waterbodies and it is further enhanced by the lunar illumination during the night. Pairwise non-parametric tests showed that the probability distributions of Fishing Cat activity under lunar illumination and tide fluctuation (D= 0.125, p-value = 0.9885 and D= 0.125, p-value= 0.9899) were similar, indicating minimal differences between each probability distribution. This study underscores the importance of protecting the mangrove habitat and controlling aquaculture expansion to ensure Fishing Cat survival in the Bhitarkanika National Park.
Abundance and social organization of male Asian elephants (Elephas maximus) in Rajaji Tiger Reserve
(Wildlife Institute of India, Dehradun, 2024) Madhusudanan, Abhimanyu; Pandav, Bivash; Lakshminarayan, N.; Mondol, Samrat
1. Asian Elephants are complex, social, and polygynous mammals living in fission-fusion societies. Male elephants are known to alternate between leading solitary lives, in all-male groups or associating with mixed-sex herds. All-male groups allow younger males to learn from older males, test strengths and spar with their peers. While much work has been done on female Asian elephant societies, studies focused on male association patterns are limited, but gaining importance in the light of human-elephant conflicts. In this study, I estimated the abundance of adult male elephants in a stretch of forest spanning over 40 km along the east bank of the river Ganga in Uttarakhand using a polygon search-based spatially explicit capture recapture (SECR) framework 2. I invested a survey effort of ~3014 km to estimate the abundance of the adult male segment of the population using a capture-recapture framework. Using a combination of morphological features, I identified 34 adult males from 124 elephant sightings. Association patterns of the male elephants, following behavioural sampling approaches were also recorded during the surveys. 3. Adult male elephant density was 0.05 (SE=0.01)/km2, and a derived abundance of 40 (SE=1.4) for the 475 km2 study area. This demonstrates that polygon search-based SECR is an effective approach in estimating elephant abundance.

M Sc Dissertation(WII)

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