Theses and Dissertations

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Start date: 2020Subject: search.filters.subject.Population estimation

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    Estimating Abundance, Habitat Use, and Acoustic Characteristics of Irrawaddy Dolphins (Orcaella brevirostris) in Chilika Lagoon
    (Wildlife Institute of India, Dehradun, 2025) Sakshi; Kolipakam, Vishnupriya; Gopi, G.V.
    This study provides a comprehensive assessment of the Endangered Irrawaddy dolphin (Orcaella brevirostris) in Chilika Lagoon, India, through an integrated approach combining visual and acoustic surveys, environmental modelling, and prey availability analysis. Visual line-transect surveys and passive acoustic monitoring (using FPODs) were used to estimate dolphin abundance and explore patterns of habitat use. Dive-time observations revealed that calves and non-calves differ in their diving behavior, with non-calves exhibiting longer and more variable dive durations. Mark-recapture analysis produced corrected abundance estimates ranging from 24 to 32 individuals, with variation influenced by observer mismatches and brief surfacing events. To assess prey availability, catch per unit effort (CPUE) surveys were conducted at 22 sites in collaboration with local fishers. The highest CPUE values were recorded in the high salinity area (Outer channel) and low salinity area (Northern sector), indicating these areas may offer better foraging opportunities. Prey community sampling across 11 sites revealed spatial differences in species richness and evenness, with some locations dominated by a few taxa and others exhibiting high diversity. Richness estimators suggested that the true species count exceeds what was observed, indicating under-sampling in certain areas. Environmental modelling using a negative binomial generalized linear model showed that salinity had a significant negative effect on dolphin acoustic detections, while dissolved oxygen and depth were positively associated but not statistically significant. The frequency ranged from 20 kHz to 200kHz with a median frequency of 98kHz. The interclick interval ranged from 850 millisecond to 1010865 milliseconds with a median of 23605 millisecond. The histogram for ICI displayed a positively skewed distribution, consistent with irregular click trains interspersed with longer pauses. The findings highlight the importance of salinity and prey availability in shaping dolphin distribution in Chilika Lagoon. The results support targeted conservation actions such as regulating freshwater inflow, protecting productive foraging zones, and expanding acoustic monitoring efforts to improve long-term management of this vulnerable population.
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    Tiger and leopard: Population ecology and resource portioning of sympatric carnivores in Kanha Tiger Reserve. M.P.
    (wildlife Institute of India, Dehradun, 2020) Kumar, Ujjwal; Jhala, Y.V.; Qureshi, Qamar
    Large investment in the form of protected areas, human resettlement, law enforcement-patrols and habitat management are made to conserve tigers and reap their benevolent umbrella role to secure India’s biodiversity. The objectives of present study are (i) the trend of tiger and leopard population (ii) demography of tigers and leopards and mechanism of their co existence. The study area was Kanha tiger reserve (area 2074 km2), a major stronghold for both species in central Indian landscape. Study investigate the estimated vital parameters of tiger demography through robust design based classical open population models in which population was open to demographic process. This study used both camera trap based mark-recapture and continuous monitoring known fate information to estimate reproductive parameters along with age specific survival and dispersal probability of tigers.
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    Status and spatio-temporal ranging behavior of leopard (Panthera pardus) in Dachigam National Park, Srinagar, J&K.
    (Wildlife Institute of India, Dehradun, 2021) Noor, Athar; Habib, Bilal; Gopi, G.V.
    This study was initiated by Wildlife Institute of India, Dehradun with support funding from the Department of Science and Technology (DST), Government of India, in December 2010 to December 2013 to estimate leopard population and prey abundance, to study the leopard feeding habits and to determine the ranging behavior of leopards in Dachigam National Park. This thesis is an outcome of the main study and has three main objectives. The first objective being to determine the population status of leopards; second is to study the ranging behaviour and habitat use by leopards and lastly to model habitat suitability for leopards in Dachigam National Park. This study also provides basic information about co-occurrence of mammalian species in the community of the moist temperate forest of the Kashmir Himalaya, India
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    Spatial abundance of ungulates and role of predation on chital (Axis axis) demography and behaviour in Corbett Tiger Reserve, Uttarakhand, India.
    (Wildlife Institute of India, Dehradun, 2022) Banerjee, Sudip; Jhala, Y.V.; Qureshi, Qamar
    To address the first objective which was to estimate the abundance of ungulates in different habitats of CTR, I have used line transect-based distance sampling approach to estimate the density of four major ungulate species (chital, sambar deer, barking deer, and wild pig) of CTR in ~520 sq. km of the Corbett National Park (CNP) region. Density was estimated using 156 spatial transects replicated 1 to 4 times over four sampling years. Both year-wise and pooled (weighted average of four years) density estimates were highest for chital followed by sambar. Barking deer had the lowest density. Chital density has remained stable over the years. Post-stratifying the densities of the four ungulates by three major habitat types of CNP (grassland, saldominated, and mixed deciduous) exhibited the highest density of chital in the grassland and lowest in the sal-dominated forest. Sambar density on the other hand was highest in the mixed deciduous and lowest in the grassland. Barking deer also exhibited a similar trend of habitat-wise density. A significant part of my thesis was focused on the objective of evaluating the precision and cost-effectiveness of three different density estimation techniques. The diverse ungulate assemblage and complex terrain of CNP provided an excellent environment to conduct this experiment.
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    Evaluating the use of Camera-Traps for population estimation of unmarked individuals using spatially explicit models in Tadoba-Andhari Tiger Reserve, Maharashtra, India
    (Wildlife Institute of India, Dehradun, 2021) Chatterjee, Nilanjan; Habib, Bilal
    Wildlife monitoring is of fundamental importance to establish baseline information, measure population changes and extinction risk. Motion-triggered camera traps are an increasingly popular tool for monitoring terrestrial species over large landscapes. Over the years, the application of camera traps has increased exponentially but studies aiming at fundamental information about sampling design and protocols are still limited to simulation studies. In this dissertation, we have used occupancy as an indicator of effective species monitoring. Occupancy has become a robust and unbiased state variable to monitor species worldwide. However, the optimal sampling design required for robust estimations of occupancy is lacking for many species.The Tadoba-Andhari Tiger Reserve (TATR) is situated in the Chandrapur district in the the Vidharbha Landscape of Maharashtra state, between 204’53” to 2025’51’’ N and 7913’13” to 79 33’34” E (Figure 6). The TATR is distributed over an area of 1700 sq. km which consists of Tadoba national park and Andhari wildlife sanctuary.
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    Habitat use and interactions of mammalian carnivores in the tropical forest of Manas National Park, Assam, India
    (Wildlife Institute of India, Dehradun, 2023) Bhatt, Urjit; Adhikari, B.S.; Lyngdoh, Salvador
    The study was conducted at the Manas National Park (MNP), East Himalayan Biodiversity Hotspot, in Assam. Previous research on MNP revealed their significance in supporting diverse wildlife, including mammalian carnivores, focusing on their distribution patterns, relative abundance indices, and population estimates. However, interactions, co-existence, and habitat use among carnivores in the park remain understudied, creating concerns for conservation efforts given the threats to biodiversity in Southeast Asia. Examining these aspects of MNP, with their varied ecological niches and body mass variations, can shed light on species interactions and habitat preferences. understanding these complex relationships and habitat use is essential for effective conservation and management strategies to ensure the long-term survival and ecological balance of carnivore communities. The thesis used camera traps to assess the richness, species composition, encounter rates, trap efforts, and threat status of mammalian carnivores in the MNP. The objectives of the study were to (a) assess diversity and species composition of mammalian carnivores, (b) determine temporal interactions among carnivores and their potential prey species, and (c) evaluate space and habitat use of mammalian carnivores in tropical forest of MNP.
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    Distribution and demography of carnivores in some parts of semi-arid landscape of Western India.
    (wildlife Institute of India, Dehradun, 2020) Sadhu, Ayan; Jhala, Y.V.; Qureshi, Qamar
    The present study reveals long-term research on tigers, elaborating their vital rates, survival parameters, and dispersal. The camera trap data to estimate the spatially explicit density, space use, and time-activity pattern of leopards. A combination of techniques that included radio telemetry, camera traps, direct observations, and photo documentation was used to obtain 3492 observations on 97 individually known tigers in Ranthambhore between 2006-2014 to estimate demographic parameters that estimates collated over nine years from 97 individually known tigers and annual density estimates of Ranthambhore tiger population from camera traps. This study aimed to estimate the demographic parameters of Ranthambhore tigers, and subsequently compare them with other tiger populations. Two species occupancy was used to estimate the spatial co-occurrence of tiger and leopard in Ranthambhore. As a long-term conservation strategy, this semi-arid tiger population needs to be conserved in a metapopulation framework. The species distribution modelling showed the importance of the PAs and also highlighted areas to direct conservation investments outside the protected areas.
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    Understanding Wolf Howls and their application in individual identification and population estimation
    (Wildlife Institute of India, Dehradun, 2022) Sadhukhan, Sougata; Habib, Bilal
    The current study addresses the knowledge gap about Indian wolf vocalisation. Alongside, it focuses on the identification potentiality of wolf howl to an individual level for using them in population estimation through mark-capture-recapture. The study also includes the howling behaviour and responses of the Indian wolf to various ecological and anthropogenic factors. Understanding the howling behaviour is key for designing howl survey methods for wolf census. As howl survey is a technique to detect wolves over long distances, the technique might provide a cost-effective solution for population estimation and a noninvasive monitoring tool for Indian wolves in human-dominated landscapes.
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    Response of small carnivore community to landscape and climatic variability in the Great Himalayan National Park Conservation Area, the Western Himalaya
    (Wildlife Institute of India, Dehradun, 2022) Bandyopadhyay, Meghna; Ramesh, K
    This study will add knowledge about the elusive and lesser-known small carnivores in a gradient of disturbed and less disturbed habitats. Objectives The study focusses on the following objectives: 1) Occurrence and abundance estimation of small carnivores across space and time along the elevation gradient. 2) Assessment of community composition of small carnivores and association with other small carnivore species. 3) Evaluation of landscape sensitivity by representative small carnivore species. 4) Distribution modelling of indicator species to anthropogenic and climatic effects in the current context Study focusses on the arrangements of small carnivores along the elevation gradient in terms of site intensity usage and abundance of small carnivores. Marked (leopard cat) and unmarked (red fox) species were considered and statistical models were used to find the overall abundance and also across the elevation gradient in space and time. demonstrates the coexistence patterns of small carnivores (red fox and leopard cat) in three dimensions; space, time and diet. The niche dynamics was assessed and compared between low human disturbance and high human disturbance areas. Study reveals how the coexistence patterns of small carnivores change with differential human disturbances.
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    Foraging ecology of Great-Slaty Woodpecker in and around Pawalgarh Conservation reserve in Western Himalaya
    (Wildlife Institute of India, Dehradun, 2024) Kaur, Sarabjeet; Gopi, G.V.; Uniyal, V.P.
    The Great Slaty Woodpecker (Mulleripicus pulverulentus, Temminck 1826) is an old-world woodpecker that prefers mature and old-growth dipterocarp forests (including Shorea robusta, Sal) across its known distribution range. The study reveals population demography, the social system and foraging behavior from logged forest and infer the distribution and home range of the Great Slaty Woodpecker, a cooperative breeding bird species, in and around the Pawalgarh Conservation Reserve in the western Himalaya of Uttarakhand state. This study presents the first census conducted for the Great Slaty Woodpecker, providing an ecological baseline for the species population estimation from its known distribution range. I inferred the home range size of each group based on 161 independent sightings of 11 family groups. These sightings represent behaviors such as foraging, nesting, roosting, vocalizations, and territory defense