Theses and Dissertations

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.

Closely related species often have similar requirements and these species need to have certain ecological adaptations to live in sympatry. Two congeneric species the Assamese (Macaca assamensis) and the rhesus macaque (Macaca mulatta) co-occurring in the Askot landscape of Uttarakhand were studied to understand the mechanisms allowing their coexistence. 2. Ecological niche differentiation for the two species was investigated by examining three possible modes of separation: activity pattern, diet and spatial use following observational protocols over a period of five months (December 2016-April 2017). Crop-raiding by macaques often results in human-macaque conflict. With the help of semi-structured interviews, attempts were made to access the level of conflict and people’s perception of these two macaque species. 3. Limited niche overlap was found between two primate species across the study duration. The Assamese macaque differed from the rhesus macaque in time spent on various activities. The former spent more time feeding and the latter in resting. Although 44% of all food items were consumed by both the species, only three of the ten major food items were shared. Assamese macaques preferred leaves and had broader niche breadth compared to rhesus macaques who fed more selectively on fruits. There was a significant difference in feeding heights, habitat and roosting site preferences of the two species. Differences in diet choice and roosting sites, in turn, resulted in differences in daily movement and home range of these species. Despite a partial home range overlap, both these species were found to be spatially segregated at a local scale. 4. The extent of niche overlap across winter and spring seasons in the area showed the greatest divergence in the diets of the two species in winter, while diet overlap was more pronounced in spring. As resources were abundant in the spring, an increase in niche overlap may not have lead to competitive interactions. Synthesis and application: Knowledge about differential resource use of macaques might help in assigning conservation priorities to the different species and their specific ecological niches along with designing species-specific management strategies. The study was able to distinguish the macaque's tendency to co-exist with humans.

Theses and Dissertations

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