Theses and Dissertations

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Start date: 2021Subject: search.filters.subject.Habitat

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    Ecology of major Invasive Alien plant species (IAPs) across various habitats in Pakke Tiger Reserve, Arunachal Pradesh
    (Wildlife Institute of India, Dehradun, 2026) Singh, Huidrom Bablin; Adhikari, B.S.
    Proliferation of invasive alien plant species poses a significant threat to the structure and function of ecosystems, making this a critical area of focus within the scientific communities. These species cause extensive damage to the biodiversity, as they are capable of altering the ecosystems and outcompete the native biodiversity. Globally, their abundance has increased dramatically in forested and other natural areas due to rapid economic growths and anthropogenic activities. To counter this alarming situation, understanding the distribution pattern, climatic influences on phenophases and ecological impact on soil by invasive alien plant species is a priority. In northeast India, studies on invasive alien plant species diversity and their impacts are very limited, especially in Arunachal Pradesh. Therefore, the present study aims to determine the patterns of distribution, phenophases and physiochemical impacts by the dominant invasive alien plant species in five forest types (Assam Alluvial Plain Semi Evergreen Forest-AAPSEF, East Himalayan Mixed Coniferous Forest-EHMCF, East Himalayan Subtropical Wet Hill Forest-EHSTWH, Non-Forest-NF and Riverine Forest-RF) of Pakke Tiger Reserve, Arunachal Pradesh. The altitudinal range of Pakke Tiger Reserve is 150- 2050 m above the sea level (490 to 6725 feet), with an average annual rainfall of 2500 mm. The current study reveals a total of 43 invasive alien plant species in the study area. However, their species richness in five forest types was in declined trend with the increase of elevation. Across the forest types, AAPSEF (30%) display the maximum level of invasion and least incursion in EHSTWHF (16%) in the current study. Among the nine species selected for the study, Chromolaena odorata (L.) R.M.King & H.Rob. was found dominant and distributed extensively in all forest types, with highest relative density (51%) in EHSTWHF and relative abundance (10%) in NF. The entire selected species shows contagious distribution pattern (<0.5) in all forest types except for Urena lobata in NF displaying random distribution (0.025 - 0.5) in study area. Ageratum conyzoides L., Chromolaena odorata (L.) R.M.King & H.Rob. and Urena lobata L. are the species with extensive distribution in all forest types in comparison to other selected species showing their dominance over the native vegetation. Moreover, maximum area cover percentage was exhibit by Chromolaena odorata (L.) R.M.King & H.Rob. followed by Ageratum conyzoides L., Mikania micrantha Kunth and Urena lobata L. across the forest types in Pakke Tiger Reserve. Forest types such as AAPSEF, NF and RF display high level of disturbances while the EHMCF and EHSTWHF have fewer incursions by invasive alien plant species in the study area. Phenological pattern on the selected species shows that Bidens pilosa L. has the longest flowering phenophases while Chromolaena odorata (L.) R.M.King & H.Rob. has the maximum fruiting duration in EHSTWHF. For leaf fall and initiation, Urena lobata L. display the longest duration in RF. Moreover, coefficient of variation shows that most of the species display asynchronous phenophases across the forest types of Pakke Tiger Reserve. Repeated measures of ANOVA also display that Ageratum conyzoides L. display difference in flowering in NF and EHSTWHF while Chromolaena odorata (L.) R.M.King & H.Rob. leaf initiation show difference in EHMCF. Correlation and linear regression display influences of climatic parameters i.e., precipitation, relative humidity, minimum and maximum temperature to the selected species in the study area. CCA also indicates that precipitation, minimum and maximum temperatures directly influence the phenophases of the selected species. However, relative humidity influences the phenophases of the selected species when in cohesion with other climatic parameters. Ecological impact on native species by invasive alien plant species was determined by collecting the soil sample of the most dominant species i.e., Chromolaena odorata (L.) R.M.King & H.Rob. across the forest types in Pakke Tiger Reserve. The result shows that clay and copper contents were high in all invaded sites while soil pH, sand, boron and water holding capacity were significantly lower in invaded plots. Out of 16 soil variables, T-test reveals that AAPSEF and NF have variation in 13 variables while EHMCF, EHSTWHF and RF have difference in 12 variables. ANOVA between the invaded and uninvaded sites also indicates significant differences in Boron, iron, copper, nitrogen, water holding capacity, clay, silt and sand. Moreover, correlation shows eight of the variables display relation between them. Furthermore, PCA indicates that INNF soil properties were different from the remaining sites. The results indicate that Chromolaena odorata (L.) R.M.King & H.Rob. alter the soil properties of invaded areas by improving the fertility, making it ideal for the proliferation process in future scenarios.
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    Species diversity and molecular study of bees (Bombus and Xylocopa) in Dehradun District, Uttarakhand, India
    (wildlife Institute of India, Dehradun, 2025) Abha Purohit
    Pollinators are fundamental to the functioning of terrestrial ecosystems, as they facilitate the reproduction of a vast majority of flowering plants and thereby sustain biodiversity and ecological stability. Globally, an estimated 87.5% of flowering plants depend onanimal pollinators for successful reproduction (Ollerton et.al. 2011). In addition to their ecological role, pollinators, particularly bees, are indispensable for global agriculture. Approximately 75% of the world’s leading food crops rely on pollination to enhance both yield and quality (Klein et.al. 2007). Agricultural commodities such as fruits, vegetables, nuts, oilseeds, and spices are especially dependent on bee-mediated pollination. Beyond agricultural productivity, pollinators provide critical services that directly influence human nutrition. By increasing the diversity, availability, and quality of nutrient-rich foods, they indirectly contribute to balanced diets enriched with vitamins, antioxidants, and essential micronutrients (Eilers et.al.2011). Thus, pollinators not only underpin biodiversity but also strengthen food security and human well-being, highlighting their ecological, agricultural, and nutritional significance. 2. Research objectives The study aims to conduct a systematic survey of Bombus (bumblebees) and Xylocopa (carpenter bees) in the Dehradun district, focusing on their taxonomy, ecology, and seasonal distribution in different habitat zones. It also seeks for identification and characterization of their habitats, with emphasis on the availability of food plants that sustain high species diversity. Molecular tools, including DNA barcoding, was applied for accurate identification of collected specimens. Additionally, the research evaluated the impact of anthropogenic pressures and other environmental threats on the survival and diversity of these pollinator groups in the study area.
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    Foraging Guild Structure and Niche Characteristics of Waterbirds in Pong Wetland, Himachal Pradesh
    (Wildlife Institute of India, Dehradun, 2025) Abhishek; Talukdar, Gautam; Gopi, G.V.; Kaur, Amarjeet
    Wetlands are one of the important habitats for waterbirds, yet the mechanism of niche segregation among the waterbird communities is understudied. This study focused on the foraging guild structure and niche characteristics of waterbirds in Pong wetland during the wintering season. The study takes into account foraging habitat (water depth, secchi depth and vegetation type) and foraging technique used by the waterbird species to understand resource partition and coexistence. The study was carried out from December 2024 to March 2025 using the point count method in two different sites of the Pong wetland i.e., Meenu khad and Gaj khad each having five replicates. The total sampling effort was 56 days with 26 days in Meenu khad and 30 days in Gaj khad. The species richness analysis of both the sites revealed Meenu khad to be more species rich than Gaj khad likely due to variation in water depth in the region, resulting in different habitat conditions. The monthly abundance of waterbirds in Pong wetland was found to be at its peak in the month of January. Generalist species such as the Eurasian Coot and Tufted Duck occupied the broadest habitat and combined niche breadth than that of specialists such as the River Tern. Furthermore, in terms of extensive foraging strategy, species such as the Northern Shoveler and Intermediate Egret occupied broader niche breadth, demonstrating behavioral flexibility in resource acquisition. The clustering of waterbird communities resulted in four functional guilds that are responsible for reducing competition and allowing species coexistence. It was found that the intraguild overlap was significantly higher than the interguild overlap (F = 54.34, p < 0.001). The null models further showed the mechanism that could be responsible for structuring the communities. It resulted in higher observed niche overlap than expected, signifying that community structure of waterbirds is largely influenced by morphological variations leading to different foraging habits, variable abundance of waterbird species and presence of abundant resources at Pong Dam. This study is the first in providing deeper understanding on seasonal waterbird abundance, niche requirements and community structure at Pong Lake. This study serves as a baseline to continue future studies in the region and assess the impacts of changing land use practices as well as changing climate on species occurrence and abundance and community structure. Furthermore, the study also showed the region to be an important staging ground for many migratory species, therefore, focusing on targeted habitat management will be crucial to support the diversity of waterbird species.are one of the important habitats for waterbirds, yet the mechanism of niche segregation among the waterbird communities is understudied. This study focused on the foraging guild structure and niche characteristics of waterbirds in Pong wetland during the wintering season. The study takes into account foraging habitat (water depth, secchi depth and vegetation type) and foraging technique used by the waterbird species to understand resource partition and coexistence. The study was carried out from December 2024 to March 2025 using the point count method in two different sites of the Pong wetland i.e., Meenu khad and Gaj khad each having five replicates. The total sampling effort was 56 days with 26 days in Meenu khad and 30 days in Gaj khad. The species richness analysis of both the sites revealed Meenu khad to be more species rich than Gaj khad likely due to variation in water depth in the region, resulting in different habitat conditions. The monthly abundance of waterbirds in Pong wetland was found to be at its peak in the month of January. Generalist species such as the Eurasian Coot and Tufted Duck occupied the broadest habitat and combined niche breadth than that of specialists such as the River Tern. Furthermore, in terms of extensive foraging strategy, species such as the Northern Shoveler and Intermediate Egret occupied broader niche breadth, demonstrating behavioral flexibility in resource acquisition. The clustering of waterbird communities resulted in four functional guilds that are responsible for reducing competition and allowing species coexistence. It was found that the intraguild overlap was significantly higher than the interguild overlap (F = 54.34, p < 0.001). The null models further showed the mechanism that could be responsible for structuring the communities. It resulted in higher observed niche overlap than expected, signifying that community structure of waterbirds is largely influenced by morphological variations leading to different foraging habits, variable abundance of waterbird species and presence of abundant resources at Pong Dam. This study is the first in providing deeper understanding on seasonal waterbird abundance, niche requirements and community structure at Pong Lake. This study serves as a baseline to continue future studies in the region and assess the impacts of changing land use practices as well as changing climate on species occurrence and abundance and community structure. Furthermore, the study also showed the region to be an important staging ground for many migratory species, therefore, focusing on targeted habitat management will be crucial to support the diversity of waterbird species.
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    Open to Invasion Patterns in Fruiting Phenology and Seed Dispersal of Lantana Camara Across Different Habitats in North India
    (Wildlife Institute of India, Dehradun, 2021) Taneja, Yukti; Page, Navendu, V.; Kumar, R.Suresh
    Lantana camara (hereafter, Lantana) is a fleshy-fruited alien invasive plant that spreads mainly through seed dispersal mediated by vertebrate frugivores. Lantana has low shade tolerance and is thus more abundant in relatively open habitats. While open habitats may facilitate better germination of seeds and growth of saplings and adults, the role of habitat type on its reproductive output (fruits) and seed dispersal remains largely unknown. Understanding this can help predict differential patterns of invasion in different habitats. In this study, I aimed to understand the influence of canopy cover and other drivers on fruiting phenology, visitation patterns of frugivores on Lantana and fruit removal of Lantana. I carried out this study in Shorea robusta- dominated. moist deciduous forest and grassland-shrubland mosaics in and around the Wildlife Institute of India (WII) campus in the Dehradun valley, Uttarakhand from August 2021 to December 2021. To determine the influence of canopy cover on fruiting phenology, I marked and monitored (every fortnight) 45 Lantana bushes across a gradient of canopy cover from late August. To determine the drivers of visitation patterns of frugivores on Lantana and the fruit removal rates of Lantana across habitats, I earned out focal plant watch on 80 Lantana bushes across a gradient of canopy cover. I used a generalized linear mixed model (GLMM) to test the effect of canopy cover and shrub volume on the fruit crop size of Lantana bushes monitored for phenology.
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    Patterns of distribution and multiscale-habitat correlates of riverine birds in the upper Ganges, Western Himalaya.
    (Wildlife Institute of India, Dehradun, 2021) Sinha, Ankita; Ramesh, K.; Jayapal, R.
    Fauna associated with riverine ecosystems vary considerably at the global scale ranging from obligate terrestrial to obligate aquatic. Birds constitute key components of wildlife along running water systems. 2. The global river bird community is diverse with 66 species, spanning across 19 families with 37 non-passerines and 29 passerines. Asia has the maximum number of species followed by South America and Africa. 3. The global distribution ranges of specialist river birds show that large areas of the world hold few or no specialist riverine birds. Richness peaks in the eastern Himalaya and the Myanmar-China border, around the Kakabo Raazi mountains where more than 15 species of specialist river birds overlap in range. 4. Species richness reflects considerable radiation in particular groups; Muscicapidae (small passerine insectivorous birds mostly belonging to the old world) in Asia, ovenbirds (Funariidae) and tyrant flycatchers (Tyrannidae)in South America, and the Pratincoles (Glareolidae) in Africa. 5. Ecological understanding and conservation efforts of specialist river birds remain rudimentary especially in the tropics where rivers are faced with a host of threats. 6. In this particular study, field surveys were undertaken to understand bird community composition and river habitat characteristics across summer (breeding) and autumn (wintering/non-breeding) seasons in the Bhagirathi basin, a major headstream of the Upper Ganges in the state of Uttarakhand in the western Indian Himalaya between years 2014 and 2018.
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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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    Patterns of Mammalian assemblages in forested riverscape in Koyna Wildlife Sanctuary, the Northern Western Ghats, India.
    (Wildlife Institute of India, Dehradun, 2021) Jelil, Shah Nawaz; Ramesh; Hayward, Matt W.
    This study deals with understanding mammal abundance and habitat status in an altered watershed, a dammed river that now forms a part of the Koyna Wildlife Sanctuary, in the northern Western Ghats, Maharashtra, India. Study aimed to understand habitat status and mammal abundance along the stream network within upstream Koyna Reservoir, 55 years after its construction. By doing this, I aimed to understand and draw conclusions on generally how reservoirs are functioning as protected areas. This study is particularly relevant and important for the threatened and unique landscapes of the Western Ghats. A systematic conservation prioritization analysis was conducted to assess which areas within Koyna should be prioritized for effective allocation of management resources. Overall, using robust modelling approaches, the thesis reports about the present status of riparian forests and mammals using these riparian areas in Koyna Wildlife Sanctuary.
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    Proximate drivers of human-tiger interface and conflict in Sariska and Panna Tiger Reserves, India.
    (wildlife Institute of India, Dehradun, 2021) Malviya, Majari; Ramesh, K.; Sankar, K.
    Human-wildlife conflict poses the most complex challenge to achieving ‘coexistence’. It has resulted in the decline of many species globally. Tigers are one of the three most conflict-prone large-bodied felids in the world. In some of its range states, about 50% of tiger deaths have reportedly occurred due to retaliatory killing by humans in response to domestic cattle depredation. Because of the implications of human-tiger conflict (HTC) on the persistence of tiger especially in human-dominated landscapes, management of HTC is of great conservation importance. However, efficient management steps can only be taken when the reasons for conflict are exposed. For this purpose, we need to identify and understand the factors operating in a conflict that determines its occurrence in a certain place and certain time i.e., the drivers of HTC. This study thus introduces an analytical framework, the conflict determinant model, to study human-carnivore conflict aimed at identifying various socio-ecological factors linked with conflict and model these factors to understand the mechanism and dynamics of HTC in the two study sites, viz. Sariska Tiger Reserve (STR), Rajasthan and Panna Tiger Reserve (PTR), Madhya Pradesh, India, with the goal to help design effective mitigation measures. To identify ecological drivers of HTC, data was collected on key habitat parameters for tigers i.e., prey, cover, water, and anthropogenic disturbance using line transect, circular plots, camera traps, and GIS. Additionally, to identify biological drivers, data on biological parameters of the tigers involved in conflict, viz. ID, sex, age, home range, and physiological stress were also collected
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    Ecology and conservation of Ichthyofauna in the Godavari River Restuarine Ecosystem (EGREE) Andhra Pradesh
    (Wildlife Institute of India, Dehradun, 2022) Paromita Ray; Johnson, J.A.; Sivakumar, K.
    This study was conducted to understand the ecological processes and functions of the estuary, including studying the role of the Godavari mangroves as fish habitats, is needed to maintain the various ecosystem services of EGREE. The three main objectives of this thesis are: 1. To study the spatio-temporal changes in fish assemblage across the different habitats in East Godavari Riverine Estuary Ecosystem (EGREE) 2. To study the trophic ecology of ichthyofauna in East Godavari Riverine Estuary Ecosystem (EGREE). 3. To study the role of mangrove forests in structuring the ichthyofauna in Coringa Wildlife Sanctuary. This study was conducted between June 2014 and May 2017 in the estuarine zone of the Godavari delta and the mangroves of Coringa Wildlife Sanctuary in Andhra Pradesh.
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    Habitat, food resource utilization of Himalayan brown bear (Ursus arctos isabellinus, Horsfield 1826) and conflict with humans in Lahaul valley, Himachal pradesh
    (Wildlife Institute of India, Dehradun, 2023) Kumar, Vineet; Adhikari, B.S.; Sharma, Lalit Kumar
    Himalayan brown bear (Ursus arctos isabellinus) is one of the top carnivores dominating the higher altitudes of the North and Western Himalayan landscape. In India, based on the 2005 estimate the approximate brown bear distribution range is reported to be 36,800 km2 , whereas only 10% of the total distribution area of the brown bear comes under the protected areas. There is very low density of brown bear lies in its distribution range throughout the Western Himalaya, in alpine meadows, scrub and sub-alpine forests of two Union Territories (Jammu and Kashmir; and Ladakh) and two Indian Himalayan States, Himachal Pradesh and Uttarakhand. Due to its inaccessible and high altitude habitat, the brown bear has been poorly studied in India, as well as in other parts of the Asian highlands.In the recent decade, the widespread exponential growth of the human population, infrastructure development, and agricultural intensification has led to the alteration of natural habitats into human-modified landscapes, bringing humans and wildlife into close proximity. In areas where brown bear and human habitation are in close proximity, brown bears feed on agricultural/horticultural crops and livestock predation leads to human-brown bear conflict and lessens local tolerance for bears. As the human settlements encroach further into remote areas, bear-human conflict escalates. Himalayan brown bear in its distribution range in India facing prevailing threats such as habitat loss, cropland expansion, anthropogenic disturbances, human brown bear conflict and climate changes. The present study was proposed to understand in detail the habitat use and feeding habits of brown bear with respect to human-brown bear conflict to develop mitigation strategies. For conducting this study, the vast geographic area of Lahual valley was stratified into different habitats and then divided into 10 km × 10 km grids for extensive study. First objective of this study aimed to understand the habitat utilization pattern of the Himalayan brown bear in selected grids of Lahaul Valley across the seasons (Intensive study area). To achieve this objective sign survey and camera trapping data was used and sixty-five logistically possible grids were surveyed across the seasons (summer and pre-hibernation), in different habitats and elevation gradients.he findings of the present study highlight a distinct seasonal pattern in habitat use of the Himalayan brown bear. In summer, bears predominantly utilized the areas with extensive vegetation cover as evidenced by a positive association with rangeland and Shannon diversity index and NDVI-summer, particularly away from the human settlements in the elevation range of 3000m to 4500m. Conversely, in the per-hibernation phase, Himalayan brown bear tends to avoid high-altitude areas with limited vegetation, opting for areas with available vegetative materials. Notably, habitat use was concentrated in the elevation range of 2800m to 3800m closer to the human settlements in comparison to summer. Regardless of the season, the Himalayan brown bear utilizes areas near roads, emphasizing the availability of anthropogenic food resources.