M Sc Dissertation(WII)

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Author: search.filters.author.Pandav, BivashSubject: search.filters.subject.Population estimation

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    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.
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    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.