Theses and Dissertations

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Author: search.filters.author.Talukdar, GautamStart date: 2020

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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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    Spatio-temporal and thermal ecology of Indian rock python (Python molurus, Linn. 1758) in Sathyamangalam and Mudumalai Tiger Reserves, Tamilnadu
    (Wildlife Institute of India, Dehradun, 2023) Vishnu, C.S.; Chinnasamy, Ramesh; Talukdar, Gautam
    The Indian rock python (Python molurus) is a Schedule I species in the Indian Wildlife (Protection) Act-1972. It is also listed as appendices I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) since they face immense survival threats due to habitat degradation and poaching. This study aimed to assess those important aspects of this species. Before the major research objectives, I reviewed the snake telemetry papers between 2007 and 2017 and identified the suitable transmitter and anaesthetic for the study. It was found that the VHF AI-2 Hollohill model was the best transmitter for the study due to the animal's body plan, whereas the Isoflurane gaseous anaesthesia can be a suitable anaesthetic agent. Understanding the microhabitats used by a species is essential for its effective conservation and management. This study objective aimed to quantify the microhabitat use of Indian rock pythons in the Sathyamangalam and Mudumalai Tiger Reserves (STR & MTR), Tamil Nadu
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    The resilence of protected areas of India to climate change: current status and future scenario
    (Wildlife Institute of India, Dehradun, 2024) Sarkar, Debanjan; Talukdar, Gautam
    This study seeks to address the gap by delving into the broader implications of climate change to protected areas of India, specifically homing in on its multifaceted impacts on biodiversity and the identification of potential refugia. Objectives ● Quantifying the climate drivers contributing to vegetation changes across biogeographic zones ● Identify climatically vulnerable protected areas ● Suggest management strategies., i.e., identifying climate-change refuge. This study examines the impact of climate change on India’s biodiversity, biogeographic zones, and protected areas (PA), and aims to identify climatically vulnerable and resilient protected areas of India to climate change. The study reviewing existing scientific literature on the nexus of climate change, biodiversity conservation and protected areas of India and highlights the current knowledge gaps in India
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    Eco toxicological and Spatial risk assessment of estrogenic endocrine disrupting compounds in Middle Ganga
    (Wildlife Institute of India, Dehradun, 2024) Shah, Ruchika; Talukdar, Gautam; Hussain, S.A.
    Chemical pollution threatens 60% of marine mammals, making it the second most significant threat to marine biodiversity. However, this alarming figure highlights the even greater risks faced by freshwater ecosystems, where biodiversity declines are happening at a faster rate than in marine environments. Freshwater ecosystems are especially vulnerable to the impacts of chemical pollution due to their limited water volume and flow, which reduces the dilution of contaminants. Their close proximity to pollution sources—such as agricultural runoff, industrial discharge, and urban waste intensifies this exposure. Furthermore, restricted natural flushing and water exchange, along with nutrient loading and additional stressors like habitat degradation and invasive species, further amplify the impacts of pollution on freshwater biodiversity. The Middle Ganga Reach (MGR), along the state of Uttar Pradesh, serves as an important habitat for endangered riverine mammals, yet faces intensified challenges to habitat suitability for these species due to various anthropogenic pressures, including EDC pollution from both point and non-point sources. Although research on e-EDCs in the river has progressed over the years, the spatiotemporal data remains incomplete and fragmented, particularly lacking in detailed characterization of point source contamination. This is a significant gap in our understanding of current risks and may result in inadequately informed and insufficient conservation efforts The objective of this thesis research was to investigate (a) the spatiotemporal distribution and load of e-E-EDCs in drains effluents and MGR (b) investigate and assess the estrogenic potential and ecological risk of selected e-EDCs to aquatic life, (c) identify high-risk zones spatially in river, and (d) assess the bioaccumulation potential of e-EEDCs in the prey species of the Gangetic dolphin, quantify the associated ecological risks, and identify suitable biomonitors for evaluating e-EDCs exposure in the MGR. The study also proposes a monitoring framework to provide guidance on monitoring and assessment of chemical contamination in Gangetic dolphin and habitats.
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    HABITAT SELECTION BY DESERT FOX (Vulpes vulpes pusilla) IN HUMAN MODIFIED LANDSCAPE OF THAR DESERT
    (Wildlife Institute of India, Dehradun, 2024) Krishnapriya, M.; Dutta, Sutirtha; Talukdar, Gautam
    Knowledge about habitat use and selection helps to assess the impact of land use change on wildlife and inform conservation management. This study aims to understand habitat use and den site selection of Desert Fox (Vulpes vulpes pusilla) in the human modified landscape of Desert National Park and it adjoins in Rajasthan. The study was conducted from January 2024 to April 2024 that include the fox breeding season. Species occupancy inside and outside protected areas were examined to understand the effectiveness of protection. Den site selection was examined by comparing habitat, resource, and disturbance variables at the scale of core usage around the den and random control points. Protected area showed a positive effect on occupancy of foxes. Desert fox was found to be using diverse habitat types for denning, however, scrubland tended to be used more than availability and grassland was used less than availability, in the study area. Agriculture did not influence den site. Foxes showed strong avoidance to areas with high human and livestock disturbances and strong preference to areas with abundant Capparis fruiting for denning. Increase in human footprint in the landscape could potentially lower the survivability and reproductive success of foxes by making them prone to direct threats from humans and subsidized predators such as dogs.
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    Richness and Compositional Responses of Ants to Land use Change
    (Wildlife Institute of India, Dehradun, 2021) Shakur, Mohammad Abdau; Talukdar, Gautam
    Human-made changes to the ecosystem are leading to the loss of biodiversity across the world. Western Ghats (WG) known for its rich biodiversity has historically undergone fragmentation and loss of its primary forest cover which has significant negative effects on biodiversity. Studies have shown that fragmentation almost invariably leads to a decrease in species richness, a pattern consistently observed across different taxonomic groups. Ants, one of the numerically dominant groups in forest ecosystems, play a vital role in many ecosystem processes and yet is one of the least studies groups within the WG landscape. The effect of land use change on ants in forests, fragments, native shaded coffee plantations and silver oak shaded coffee plantations was studied in the Kodagu district of Karnataka, India. We hypothesized that habitat heterogeneity would decrease from forests to fragments to native shaded coffee plantations and silver oak shaded coffee plantations and this would consequently lead to a decline in the richness and change in species composition of ants along this gradient. To test this prediction, ants were sampled along transects in the four-land use types using both pitfall traps and modified wrinkler extractors. As expected, there is a reduction in structural complexity across forest, fragments, native shade coffee and silver shade coffee plantations. We found that at the level of a transect, species richness reduced from forests to coffee plantations. Interestingly, the trend reversed when viewed at the scale of the land use, where all the forest sites together were the least species rich while the coffee plantations collectively showed the highest species richness. With respect to species composition, we found that coffee plantations had species adapted to drier environments whereas species inhabiting leaf litter were primarily found in forests and fragments. Coffee plantations with human residence inside had higher species compared to those not inhabiting. This study highlights the importance of scale for assessing the biodiversity potential of human modified habitats and for assessing their conservation potential.