M Sc Dissertation(WII)

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    Breeding biology and diet of Tawny eagles (Aquila rapax) in desert National Park, Rajasthan, India
    (Wildlife Institute of India, Dehradun, 2026) Varma, Gayathri; Kher, Varun S.
    The Tawny Eagle (Aquila rapax), is raptor species, found across the Indian subcontinent, widely spread and poorly studied. There is very limited quantitative information present on the nest-site selection, breeding behaviour and diet selection of Tawny Eagles. This study investigates the factors influencing habitat selection, breeding ecology and diet composition of the population of Tawny Eagles in the Thar desert landscape of Rajasthan, India, during the 2025-2026 breeding season. This study aimed to provide a baseline understanding of the species ecology by examining nest-site selection, spatial distribution of nests, parental behaviours, provisioning behaviours and seasonal changes in prey compositions. Nest search was conducted across approximately, 2000 km2, with approximately 4000 km of nest search effort with active nest tree characteristics mapped, and distance between the nest and the protected grasslands calculated. A total of ten nests were found across the study area, with all nest occurring within, or in close proximity to the protected grasslands in Desert National Park. Nine out of ten nests were either inside enclosures or located immediately adjacent to them, with an average distance of 1.56 km from enclosure boundaries. Nest trees were predominantly Prosopis cineraria, with nesting trees averaging over 7.5 m in height and providing large crown structures suitable for nest placement, with all nests being placed at the top of the tree. As all the nests were recorded in only a small part of the study area, a rapid population survey was conducted across the study area to determine the spatial distribution of the species across the study area. Raptor surveys covering 734.78 km across 63 grids recorded 14 Tawny Eagle sightings, confined largely to areas where nests had been located. Breeding behaviour was studied using focal observations and CCTV monitoring across active nests, generating approximately 900 hours of behavioural data. Breeding was found to occur in the winter months, with most eggs being laid in December and January, hatching in the months of January and February, with fledging occurring by the end of March through April. Results showed differences in parental roles, with females primarily responsible for nest attendance and chick care, while males acted as the primary providers of prey. Female nest attendance decreased as chicks matured, while chick vigilance increased with age. Provisioning behaviour demonstrated seasonal variation, with Spiny-tailed Lizards (Saara hardwickii) becoming the dominant prey item during warmer months. Diet composition was assessed using pellet analysis, CCTV observations, and drone surveys, resulting in 224 prey records from nine nests. Tawny Eagles showed dietary flexibility, with mammals (41.9%) and reptiles (40.1%) comprising the majority of prey items. Diet composition changed significantly across months and nesting stages, with a shift from mammalian prey during colder months towards increased reptilian prey as temperatures rose and Spiny-tailed Lizards became more available. Overall, this study highlights the importance of protected grassland habitats within Desert National Park for supporting Tawny Eagle populations by providing suitable nesting structures, reduced disturbance, and productive foraging habitats. The findings provide the first detailed quantitative assessment of habitat selection, breeding behaviour, and diet composition of Tawny Eagles from the Indian population and establish a foundation for future long-term studies on population status, reproductive success, and conservation requirements of this species.
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    Population and behavioural responses of rodents and reptiles to woody encroachment in the Thar desert
    (Wildlife Institute of India, Dehradun, 2026) Pawar, Himani; Dutta, Sutirtha; Kher, Varun
    Woody encroachment is increasingly modifying open ecosystems worldwide, often altering trophic-level interactions and species composition. In the Indian Thar Desert, Calotropis procera is rapidly expanding across grassland and scrubland habitats, but its ecological consequences for desert fauna remain poorly understood. This study assessed the effects of varying levels of Calotropis procera encroachment on habitat structure, predation pressure, and behaviour and abundance of nocturnal rodents and two diurnal lizard species in and around Desert National Park, Jaisalmer. Field surveys were conducted across no, moderate, and high encroachment levels of C. procera during 2025–2026. Responses of nocturnal rodent community were assessed through burrow counts and giving-up density (GUD) experiment. Reptile responses were assessed through abundance surveys and flight-initiation distance (FID) experiment, and clay model experiment was designed to quantify predation pressure. Rodent abundance, measured through active burrow counts, declined from no encroachment plots to moderate and high encroachment levels. Conversely, giving-up density at artificial food patches was greater in no encroached plots - indicative of greater predation risk perception - compared to moderately and highly encroached habitats. Lunar illumination interacted with encroachment level to influence rodent foraging decisions, indicating the role of habitat structure and environmental conditions in shaping behavioural responses to predation risk. Reptile species exhibited contrasting responses to woody encroachment. Acanthodactylus cantoris showed declines in abundance with increasing encroachment. Behavioural response mirrored this pattern. Flight-initiation distance of Acanthodactylus cantoris decreased substantially with increasing encroachment. In contrast, Trapelus agilis occurred at higher densities in highly encroached areas than non-encroached areas and its FID was primarily influenced by refuge availability and starting distance rather than encroachment level. Predation-risk experiment revealed context-dependent effects of encroachment. In scrubland habitat, predation was faster in moderate and high encroachment plots than in no encroachment. Habitat influenced predation pressure too, as clay models faced higher predation rate in grassland than scrubland. This study demonstrates that woody encroachment produces species-specific ecological consequences, and continued expansion of Calotropis procera has the potential to reshape community composition through behavioural responses and trophic interactions, in the Thar Desert. Management interventions aimed at maintaining and preserving open habitats may therefore be important for conserving faunal diversity in this important conservation ecosystem.
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    Ant-ics and appetites: mapping ant (Formicidae) diversity and resource selection in Agumbe
    (Wildlife Institute of India, Dehradun, 2026) Biju, Ashwati; Gautam, Ritesh Kumar; Kolipakam, Vishnupriya
    Ants are important components of terrestrial ecosystems, yet information on their diversity, behaviour, and resource use in non-protected landscapes of the Western Ghats remains limited. This study investigated ant diversity, community composition, behaviour, morphometrics, and resource selection across forest patches, grasslands, and areca plantations in the Agumbe landscape of the central Western Ghats. Field surveys were conducted between December 2025 and March 2026 using visual encounter surveys and active hand collection. Ant diversity, abundance, community composition, behaviour, and morphometric traits were documented. Resource selection experiments were conducted on Trichomyrmex colonies using sugar, rice, and seeds that differed in physical texture. A total of 75 ant species, 423 occurrence records, and 10,284 individuals were recorded. Forest patches supported the highest species richness, abundance, and diversity, while plantations and grasslands supported fewer species. Community composition differed significantly among habitat types, with habitat characteristics influencing ant assemblages more strongly than stream position. Behavioural observations documented a range of ecological roles, including predation, scavenging, honeydew collection, seed collection, brood transport, recruitment, and nest maintenance. The study also recorded ten putatively undescribed species, new state records, and worker polymorphism in Lepisiota wroughtonii. Resource selection experiments showed a clear preference hierarchy of Sugar > Rice > Seeds, indicating that resource characteristics might influence foraging decisions. The findings highlight the ecological and taxonomic importance of the Agumbe landscape and provide baseline information on ant diversity, behaviour, and resource use in the central Western Ghats. The study also emphasizes the importance of forest patches for conserving ant biodiversity in human-modified landscapes.
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    Influnece of prey availability and abiotic factors on habitat utilization of mugger crocodile (Crocodylus palustris) and interactions with Fishermen in the Moyar-Bhavanisagar landscape
    (Wildlife Institute of India, Dehradun, 2026) Thompson, Bryan Rana; Gopi, G.V.; Das, Abhijit
    Crocodilians are considered to be apex predators of freshwater ecosystems, yet little is known crocodilians often compete with fishermen over fish resources. This study aims to measure the influence of prey availability (fish biomass) and abiotic features on the habitat utilization of mugger crocodiles in the Moyar river and to quantify crocodile-caused net damages and the associated costs experienced by fishermen in the Bhavanisagar reservoir. Model selection revealed that fish biomass was the best fit model for crocodile habitat utilization, along with sandy banks (which was most preferred for basking) and wider river sections, which showed weaker model fit for habitat utilization. Questionnaire surveys involving fishermen and experimental net monitoring in the reservoir revealed that the perceived frequency of crocodile caused net damage is approximately 2.2 times higher than the observed frequency of net damage. The mean estimate of losses experienced by fishermen over a four month period in the reservoir due to crocodiles was calculated to be approximately Rs. 32,029. Nets placed closer to the bank experienced more damage by crocodiles than nets placed further from the bank. This study highlights the importance of prey availability and scientific management and monitoring of habitat for crocodile populations and provides baseline information on fishermen-crocodile conflict and can aid in informing stakeholders in implementing mitigation measures and compensation schemes.
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    Altered habitat alter habits; Behaviour and space use of Asian elephants in the Valparai Plateau
    (Wildlife Institute of India, Dehradun, 2026) Komarla, Joshika; Nigam, Parag; Kumar, Ananda; Nath, Anukul
    As habitat loss and fragmentation continue to increase, mega-herbivores such as Asian elephants (Elephas maximus) increasingly traverse mixed-use landscapes where human-elephant encounters are frequent. Such encounters may influence elephant behaviour by altering activity patterns over time, modifying the relative frequencies of behavioural events, and shaping the behavioural repertoire exhibited. In this context, I examined the effect of human presence and associated activities on elephant behaviour on the Valparai Plateau, a rainforest-plantation mosaic in the Anamalai Hills of the Southern Western Ghats. Behavioural observations were conducted over a 104-day field season using 370 instantaneous group scans and 499 focal observations of identified individuals. My findings suggest that human presence did not have a measurable impact on the behavioural composition of time activity patterns; however, encounter characteristics – particularly crowd size and human identity – did account for variations in these patterns. Increasing crowd size was associated with a 10 % reduction in predicted time allocated to foraging. Behavioural events such as vigilance, avoidance, and agitation were more sensitive to anthropogenic influence, with effects evident in both coarse- and fine-scale analyses. The odds of stress-induced behaviours were sevenfold in the presence of humans; however, beyond a threshold distance of approximately 70 meters (69.9 meters), the likelihood of such responses declined substantially. Proximity to elephants and human identity were important predictors for this response. Additionally, different human groups elicited different stress-induced responses, with Forest Department personnel eliciting more avoidance and agitation responses than expected; however, this pattern requires further quantitative assessment. Herd cohesion was not affected by human presence and was weakly affected by encounter characteristics, with biological parameters like age and sex explaining the pattern better. Habitat selection analysis using Manly’s Selection Ratio suggests that natural habitats such as forest fragments, riparian sections, as well as Eucalyptus stands were preferentially selected for, and used disproportionately to their availability, whereas dominant landscape features like tea and coffee plantations , were used less than expected relative to their availability, during daylight hours. These findings suggest that elephants inhabiting mixed-use landscapes with a long history of both human use and elephant activity may tolerate human presence at a broad level, but certain encounters may still be perceived as risky
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    Comparison of small carnivores detection rates between two different leopard density regimes in Kuno National Park
    (Wildlife Institute of India, Dehradun, 2026) Namdev, Srajal; Kawlni, Lallianpuii; Kolipakam, Vishnupriya; Bipin, C.M.
    The study assessed the detection patterns of small carnivores in Kuno National Park using a camera-trap survey conducted across two sampling areas, blocks representing contrasting leopard density regimes. Camera traps were deployed using a systematic 0.5 km² grid design with approximately 700 m spacing between stations to maximize detections of small carnivores while maintaining standardised sampling. A total of ten small carnivore species were targeted, and Relative Abundance Indices (RAI) were calculated to compare detection rates among species and sampling blocks. Another study design with trail cameras on the same blocks was used to investigate the small carnivore community in two blocks representing high and medium density areas to understand community composition between the two study areas, although some species differed in their relative abundance. Small Indian civet, leopard, and golden jackal were detected more frequently in the high-density block, while jungle cat was relatively more common in the medium-density block. Spatial and temporal analyses indicated that most small carnivore species shared the same habits and were active during similar periods of the day. However, some species delayed their visits after another carnivore had recently used the same location, suggesting that coexistence is maintained mainly through short-term temporal avoidance rather than by occupying different habitats. This study also evaluated the effect of camera-trap sampling scale (grid size) on Relative abundance Index (RAI) showed that common species which were detected consistently through out the camera trap with adequate sample size produced estimates with lower coefficient of variation comparative to rarely detected species which became increasingly variable as sampling scale increased. These findings highlight the importance of using finer camera-trap grids when monitoring smaller species with less movement or home ranges.
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    Dynamics of plant and insect communities across shifting cultvation fallow in Arunachal Pradesh, Eastern Himalaya
    (Wildlife Institute of India, Dehradun, 2026) Sena, Mencho
    Shifting cultivation or jhum is a form of agriculture practice that is practiced by several communities around the world. In jhum cultivation, a patch of forest is slashed, burned, and cultivated for a limited period of time, and later on the patch is left for the regeneration vis a vis recovery of vegetation. Ecologically, such habitats provide a clear disturbance gradient to understand biodiversity recovery, including the process of establishment. Several studies have been carried out in the tropical forest around the world; however limited studies have looked at the recovery in the shifting cultivation landscape of North Eastern region in general and specifically in Arunachal Pradesh. The present study was conducted in Nampong, Changlang district of Arunachal Pradesh to investigate the dynamics of plant communities across shifting cultivation fallows of different ages. The vegetation was sampled across five different age classes vis-à-vis., 1, 5, 15, 25, 35 and forest as a control site. For vegetation sampling, 10m circular nested plots were used to sample for trees and 3.5m circular plots were used to sample for shrubs. To understand the community composition, diversity indices using the vegan package in R, following which a species accumulation was run to check sampling adequacy, were estimated. Following, which a Non-Metric Multidimensional Scaling (NMDS) was run to see how communities changed across fallows, followed by Indicator species Analysis and Similarity Percentages (SIMPER) analysis. Generalized Linear Model (GLM) with Poisson was run to check which factors influence the species richness. Based on the sampling and field observations, change in communities across fallows of different ages, with the forest having the highest species count, was observed. Simpson showed how diversity changed across fallow along with a decrease in 25-year-old which may be due to the presence of several species of Bamboo and Musa. NMDS showed a distinct pattern across age class, though there were overlaps in the mid-successional changes. Further, indicator species analysis was used to understand the association of species with respect to successional stages; such as Mesua ferrea, Terminalia chebula were associated with forest, Agalaia edulis and Albizia sp. with 35 and 25-year-old fallows, and species such as Zanthozyllum rhetsa in the early fallows. The SIMPER analysis showed the dissimilarity in the species across fallows of different ages, which showed that Trema orientalis, Macaranga denticulata, Croton persimilis, bamboo species, and Musa species contributed to differences among successional stages, and species such as Baccaurea ramiflora and Mesua ferrea were the species distinct in forest classes, suggesting the requirement of longer periods of recovery for the fallows. The understory communities of young fallows were dominated by invasive species such as Chromolaena odorata, Erigeron sumatrensis, and Mikania micrantha. Their abundance declined with increasing fallow age, indicating that canopy development and habitat recovery reduce the dominance of invasive species. Older fallows and forest sites increasingly consisted forest-associated species such as Gnetum montanum, Calamus spp., Phrynium pubinerve, and Entada sp., reflecting progressive recovery of understory vegetation. Model selection based on AICc identified fallow age as the strongest predictor of both tree and understory species richness, highlighting the importance of successional stage in shaping vegetation recovery. The influence of topographic and spatial variables was comparatively weaker. The study highlights the importance of protecting the remnant forested areas, and avoiding as well as reducing fallow cycles for the biodiversity to be resilient in the shifting cultivation landscapes of Arunachal Pradesh.
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    Density estimation and habitat selection of obligate grassland species in DÉring Memorial Wildlife Sanctuary, Arunachal Pradesh
    (Wildlife Institute of India, Dehradun, 2026) Sunny, Nama
    Riverine alluvial grasslands of the Brahmaputra floodplains are among the most dynamic and threatened ecosystems in India. These floodplain grasslands, maintained by annual flooding and sediment deposition, host a unique assemblage of obligate grassland birds dependent on early and mid-successional habitats. However, quantitative information on the population status and habitat requirements of these species is limited especially in the riverine grasslands of D'Ering Memorial Wildlife Sanctuary, Arunachal Pradesh. In this context, the present study was designed to estimate the population density of obligate grassland birds and to explore the influence of habitat characteristics on their distribution in this dynamic floodplain ecosystem. The study was conducted across the three management ranges of D’Ering Memorial Wildlife Sanctuary using 252 systematically distributed point count stations. Bird surveys were conducted using passive point counts and call-playback surveys while acoustic triangulation was used to estimate the position of vocalising birds for distance sampling analyses. Habitat selection was assessed using micro-habitat variables, grass species composition, vegetation structure and landscape attributes such as island age and island size. Generalized Linear Models (GLMs) were used to identify habitat variables associated with species occurrence while community level responses were assessed using Non-metric Multidimensional Scaling (NMDS). When comparing survey methods, call playback greatly enhanced detectability of all four focal species by eliciting vocal responses from individuals hidden in dense grasslands. However, passive aural point counts produced more precise density estimates with consistently lower coefficients of variation, indicating that observations made under natural behavioural conditions better satisfied the assumptions of distance sampling. The successful application of acoustic triangulation further demonstrated its usefulness for estimating detection distances of vocally active grassland birds in dense alluvial grasslands where direct visual observations were often not possible. Habitat‐selection analyses indicated that obligate grassland birds were influenced primarily by vegetation structure, grass composition and floodplain succession rather than simply habitat area. The Saccharum spontaneum–Typha latifolia grass assemblage was the most important predictor of species occurrences for all four focal species, and taller grasslands were consistently favoured over shorter vegetation. Three of the four focal species had higher probabilities of occurrence on younger alluvial islands, indicating a strong association with early-successional floodplain habitats maintained by natural flooding. Community-level analyses further demonstrated a clear ecological separation between obligate grassland birds and habitat generalists along vegetation and successional gradients. Obligate species were associated with younger islands dominated by tall-grass communities, whereas habitat generalists occurred more frequently on older islands characterised by increasing woody vegetation. These results emphasize the importance of flood-driven succession in structuring both species-specific habitat selection and overall composition of the grassland bird community .the results demonstrate that conservation of obligate grassland birds requires the maintenance of the ecological processes that sustain floodplain grasslands rather than simply protecting static habitat patches. Passive aural point counts combined with acoustic triangulation provide a robust structure for long-term monitoring of cryptic grassland birds, while maintaining natural flood regimes and a heterogeneous mosaic of grasslands across different successional stages is likely to be fundamental for sustaining the tall-grass bird guild of D'Ering Memorial Wildlife Sanctuary. The study provides the first quantitative baseline on population density and habitat selection of obligate grassland birds from this protected area and offers a foundation for future ecological research and long-term monitoring of riverine grassland ecosystems.
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    Nutritional ecology, movement patterns and herd dynamics of Nilgai (Boselaphus tragocamelus) in Kuno National Park, Madhyra Pradesh
    (Wildlife Institute of India, Dehradun, 2026) Vyas, Tanya; Kolipakam, Vishnupriya; Habib, Bilal; Bipin, C.M.
    Despite the various types of research done before on the nilgai, very little focus was given to what actually propelled forth their propensity to raid crops. This study was meant to delve into the factors that could possibly lead to crop raiding by nilgai. In context of the semi-arid zone, nutrition played a factor for nilgai that lived in places overrun by invasives, but did not provide any advantage to nilgai with access to natural vegetation. Through Manley’s selection ratios, it was found that nilgai select for savannah, especially at night, proving a negative association with forests. Models run for finer structural cues showed a negative selection for elevations, slope, hills and mixed forests. Avoidance of predators was seen despite lack of actual attack. Herd dynamics showed changes daily and across the breeding season. And finally, many novel behaviours of nilgai were noted; there is potential for further research on their social structure.
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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.