Theses and Dissertations

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Start date: 2020Subject: search.filters.subject.Waterbirds

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    Population dynamics and breeding habitat use by colonial waterbirds nesting at the Kokkare-Bellur Community Reserve, Southern Karnataka
    (Wildlife Institute of India, Dehradun, 2026) Mahapatra, Aksheeta; Kumar, R. Suresh
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    Study on waterbird assemblages of the Middle Ganga river
    (Wildlife Institute of India, Dehradun, 2025) Aftab; Mathur, V.B.; Hussain, S.A.
    The Ganga River, one of Asia's most biodiverse riverine systems, exemplifies this ecological significance, hosting a rich assemblage of aquatic species, including over 150 waterbird species, and threatened taxa such as the Gangetic River dolphin, gharial, and Indian skimmer. However, these ecosystems face severe threats from climate change, habitat degradation because of anthropogenic activities, including unsustainable development, and pollution, leading to an estimated 10,000– 20,000 freshwater species being extinct or at risk of extinction globally. In India, the Ganga River is significantly impacted by the over-extraction of water from dams and barrages, industrial and sewage effluents, sand mining and riverbed agriculture, resulting in significant biodiversity loss. Waterbirds are key indicators that reflect the health of wetland and riverine ecosystems, owing to their sensitivity to environmental changes. Their roles as pollinators, seed dispersers, predators, and nutrient cyclers emphasise their ecological importance. In the Gangetic plains, waterbirds rely on the dynamic hydrological processes of rivers and associated wetlands for feeding, breeding, and roosting. Yet, these habitats are under immense pressure from urbanisation, agriculture, and pollution, with up to 40% of India's wetlands lost over the past 50 years. The middle stretch of the Ganga River, supporting rich diversity of waterbirds and other aquatic fauna, remains understudied, with limited comprehensive data on waterbird assemblages and their responses to a range of environmental and anthropogenic factors. This PhD thesis investigates the spatio-temporal patterns of waterbird assemblages along the middle stretch of the Ganga River, aiming to address critical knowledge gaps in their status, distribution, and ecological dependencies. The study pursues four key objectives: (1) to determine the status, distribution, and assemblage patterns of waterbirds; (2) to identify habitat features governing waterbird assemblages; (3) to assess the impacts of anthropogenic pressures; and (4) to prioritise areas for waterbird conservation. Through systematic surveys and ecological assessments, this research seeks to generate comprehensive data on waterbird diversity and evaluate the influence of habitat characteristics, such as channel depth and width, bank features, and water quality, alongside anthropogenic stressors like sand mining, solid waste dumps, pollution, and habitat fragmentation.
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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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    Status, habitat use and factors affecting breeding waterbirds of Changthang Wildlife Sanctuary, Ladakh (India).
    (Wildlife Institute of India, Dehradun, 2020) Mahar, Neeraj
    Tourism has evolved as an alternative livelihood for the local people and has reduced their direct dependencies on natural resources and perhaps indirectly contributed towards nature conservation. However, unregulated tourism activities have led to degradation of natural systems and increased the ecological vulnerabilities of local communities. Often, tourism and other developmental activities related disturbances collide with the peak season for several biological processes and affect the ability of natural system to revive and restore itself. In case of waterbirds these disturbance affect the breeding success. Other than anthropogenic activities, domestic dogs, apparently the most abundant carnivores in the world, pose a major threat to local wildlife. Recent studies have determined waterbirds as an important part of their diet. The existing literature clearly suggested that there was a huge information gap regarding Trans-Himalayan wetlands and their avifaunal characteristics. Previous studies were either site specific or species-specific, and thus, landscape level base line data was either scanty or unavailable. The Trans-Himalayan wetlands of India are increasingly under anthropogenic stress which is affecting their ecological structure and functions, especially the breeding birds. Blacknecked crane (BNC) is one of the flagship species of these wetlands. With the above background, I decided to study and understand their ecology and major threats faced by waterbirds and wetlands of Changthang Wildlife Sanctuary (CWLS). The objectives for this work were to (1) assess the population status and habitat use by waterbirds, (2)evaluate the factors affecting the breeding waterbirds, and (3) assess change in the wetland area.