Theses and Dissertations

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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.
Nesting ecology of colonial waterbirds at Bhitarkanika mangroves, Orissa
(Wildlife Institute of India, Dehradun, 2010) Gopi, G.V.; Pandav, Bivash
Colonial nesting is an important feature among a majority of the members of Pelicaniformes and Ciconiiformes. The nesting colonies of these birds that represent spatial and temporal clumping of nests are popularly referred to as heronries. One of the largest heronries in India is located in the Bhitarkanika mangroves, along the east coast of India. Birds use five species of mangrove trees for nesting which include Excoecaria agallocha (Guan), Heritiera fomes (Bada Sundari), Cynometra iripa (Singada), Hibiscus tiliaceus (Bania), Tamarix troupii (Jagula) for nesting in the heronry. . The breeding birds in this mixed species colony are Asian Openbill, Great Egret, Intermediate Egret, Little Egret, Cattle Egret, Grey Heron, Purple Heron, Black-crowned Night Heron, Little Cormorant, Darter, and Black-headed Ibis. The heronry in Bhitarkanika is located in an island covered with mangrove vegetation. The availability of large number of nest trees in terms of the mangrove forest and foraging areas in terms of the wetlands inside the forest and the paddy fields surrounding the forest are believed to be the factors favouring such large congregation of breeding water birds in the heronry
Effect of habitat characteristics on waterbird diversity along river ganga in Allahabad, Uttar Pradesh
(Wildlife Institute of India, Dehradun, 2017) Kumar, Ankit; Gopi, G.V.; Hussain, S.A.
Riverine floodplains are a mosaic of different habitat available in the riverine area. It is extensively used by an array of flora and fauna. It supports a huge biodiversity by providing habitat as a resource to various taxa. Many waterbird species are directly and indirectly dependent on the riverine floodplains and use riverine habitat at a certain stage in their life cycle. The area also supports a high diversity of wintering waterbirds. Migratory bird takes refuge in the area during the severe winter in their native habitat. Habitat-specific species use different types of habitat present in the riverine floodplain. The riverine system also has an intricate relationship with the humans. Since a long time, these habitats are subjected to overexploitation that affects the natural ecological processes and the functioning of river. Degradations of floodplains of the major rivers of the world by alteration of water flow, encroachment in river islands and collection river bed materials, discharge of urban and industrial effluents, are threatening the biodiversity of rivers and their associated wetlands. The effect due to different levels of the disturbance is unknown on the diversity and abundance of waterbirds. On these lines, I conducted my study focused on identifying what are the habitat characteristics which is affecting the abundance and diversity of waterbirds and what are the anthropogenic factors affecting its diversity and abundance. The study was carried out in Allahabad District of Uttar Pradesh. It is known for the confluence of two major rivers of India, river Ganga, and its tributary river Yamuna

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