PhD Theses (SACON)
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Item Population dynamics of the Edible-Nest Swiftlet Aerodramus Fuciphagus Inexpectatus in the Andaman Islands(SACON, 2024) Prathamesh, H.G.; Manchi, Shirish S.Population dynamics play a fundamental role in ecological research and have important implications. It refers to the study of how the size and composition of populations of organisms change over time and in response to various factors such as birth and death rates, immigration and emigration, environmental conditions, resource availability, and interactions with other species. Many researchers have long studied terrestrial avian population dynamics; however, birds in hypogean environments, such as the Edible-nest Swiftlet, did not receive much attention. The Edible-nest Swiftlet (Aerodramus fuciphagus inexpectatus) is a cave-dwelling bird studied primarily in ex-situ habitats due to its economic importance. The studies in wild or urban areas majorly focus on breeding biology, ecology, habitat, and population trends. However, many aspects of population dynamics are never attempted due to a lack of resources and practical difficulties, such as in the Andaman Islands. Therefore, this study aims to investigate the population dynamics of the Edible-nest Swiftlet in the Andaman Islands. The study aims to investigate the various aspects of population dynamics: site fidelity, colonial sex ratio, and inter-colonial dispersal patterns, considering the biotic and abiotic factors influencing these traits. The study overall intends to provide valuable insights into the swiftlet’s research and conservation.Item Comparative assessment of select faunal taxa with reference to various growth stages of paddy in organic and non-organic fields of Kathiramangalam, Tanjavur District, Tamil Nadu(SACON, 2021) Chaithra Shree, J.; Pramod, P.Agro-ecosystems cover 43% or India's land area and also harbour wildfire. The paddy is a unique ecosystem that is known to support diverse wildlife in a short period. being a man-managed ecosystem. The change in management practices are known to impact the biodiversity of agro-ecosystems. The biodiversity supported by the paddy fields or adhiramanagalam were studied using select indicator taxa vi:. birds, butterflies and odonates and their communities were compared between two cultivation regimes viz. Organic and non-organic. with the following objectives I. To study the Community structure and variability of select faunal indicator taxa supported by the paddy fields. 2. To compare the changes in the community of select faunal taxa across paddy growth stages between organic and non-organic paddy cultivation regimes. These objectives were achieved by collecting species abundance data on birds, butterflies and odonates. during two cropping cycles of paddy by strip transect method. One Km transect with 50 m breadth was marked in paddy fi elds under organic and non-organic cultivation regimes each. The vegetation in the sampling area was recorded. The environmental, habitat conditions and physico-chemical water parameters wereItem Polycyclic aromatic hydrocarbon contamination in Pallikaranai wetland, Chennai, Tamil Nadu, India; Fish as an Indicator.(SACON, 2020) Mythreyi, D.; Muralidharan, S.Enormous quantities of man-made chemicals are being used every day to meet the ever increasing food, energy, transport and industrial demands. During the past few decades, there has only been a steady increase in the use of these chemicals leading to their excessive presence throughout the global environment. Wetlands, being the most fragile ecosystems have suffered the maximum. Extensive stretches of wetland habitats have been altered and destroyed. Among the gazillion types of chemicals, Persistent Organic Pollutants (POPs) are significant because they are resistant to degradation in the environment and biota. Due to their fat soluble nature and resistance to degradation, ingestion of certain POPs by fauna leads to bioaccumulation throughout their lives, generally in fat tissues, and biomagnification through food chain. Among the POPs, Polycyclic Aromatic Hydrocarbons (PAHs) are highly prevalent in vertebrates, particularly fishes. Polycyclic Aromatic Hydrocarbons (PAHs) are a unique class of POPs constituted by hundreds of individual organic compounds. These ubiquitous environmental contaminants are wide-spread in the air, bonded to particulate matter and readily bioavailable. Studies have demonstrated the carcinogenic, mutagenic and teratogenic behaviour of many of the PAHs. Based on their properties, 16 PAHs are listed as “priority pollutants” by the U.S. Environmental Protection Agency (EPA). These 16 PAHs are being measured and monitored in different environmental components in ecosystem throughout the globe.Item Ecological impacts of roads on mammals and integrity of the Central Indian Tiger Landscape(Wildlife Institute of India, Dehradun, 2023) Saxena, Akansha; Habib, Bilal; Rajvanshi, AshaRoad networks are increasing at an alarming pace worldwide, but most rapidly in developing countries like India. The drivers of road building in such countries include the need to make the benefits of development accessible to citizens in the remotest corners. However, road building in ecologically rich and sensitive regions can have severe repercussions for the wildlife in these regions. Road construction leads to destruction of habitats and physically disconnects previously contiguous landscapes. Traffic on roads directly cause wild animal mortality, cause changes in behaviour of wildlife by altering patterns of space use, and in the long-term can cause populations to diminish through either loss due to mortality, or by isolation of neighbouring populations by creating a barrier to their movement. Through this study, I aimed to understand the responses of a large mammal community to road-related disturbance through different methods, and form a basis for identifying and prioritising road stretches for mitigation of impacts on the large mammal community. The study was based in the central Indian tiger landscape which has one of the greatest potentials for long-term tiger conservation in the country, and at the same time is also facing incremental rates of road infrastructure development. The focal study species included the tiger, its co-predators and primary prey. The study is the first long-term research on the ecological impacts of roads conducted in an important tiger conservation landscape. It has direct management implications for understanding varied species responses to roads, mitigation requirements at different road types and forest protection types, and for landscape-scale prioritisation of sites for mitigating barrier and collision risk.Item DIVERSITY AND DISTRIBUTION OF BIRDS IN BHARATHAPUZHA RIVER BASIN, KERALA(SACON, 2024) P N , Anoop Raj; Kumara, H NBharathapuzha also known as the Nila River is the second-longest river in Kerala. It is considered as one of the most important rivers in Kerala for its ecological, cultural, and historical importance. Thus, it is known as the cradle of civilisation in Kerala. This river originates from the northern and southern rims of the Palakkad Gap. It flows towards the west through the Coimbatore district in Tamil Nadu and the Palakkad, Thrissur, and Malappuram, districts of Kerala before draining into the Arabian Sea. The river's total length is 209 km with a drainage area of 6186 km2. Chitturpuzha, Kalpathipuzha Gayathripuzha, and Thoothapuzha are major tributaries of this river. Birds are considered as indicators of habitat quality. They play an important role as predators, prey, pollinators and scavengers in nature. Understanding the natural bird assemblage, its patterns, and its process will help prioritize the potential conservation areas. Many researchers have attempted to study bird communities in the different habitats in the Western Ghats. Their observations on birds provided useful information to understand the distribution trend of birds. Most of such studies focused on the forest ecosystems in the protected area network. Understanding the distribution pattern of birds and their drivers in highly disturbed ecosystems outside the protected area network is less attempted. From the origin to the mouth, the river passes through various ecosystems and topographic conditions. Bharathapuzha originates and runs through forest ecosystems in the Western Ghats hill ranges initially, then travels through various human habitations, and agrarian lands and finally reaches the Arabian Sea. So, it supports bird communities of different forest ecosystems, agrarian lands, water bodies, and human habitations including the urban areas. Most of these ecosystems are located outside the protected area network and are vulnerable to anthropogenic pressures. Deforestation in the hill region, construction of check dams, indiscriminate sand mining, the spread of weeds and invasive plants inside the river channel, expansion of monoculture plantations, encroachment and water pollution are the major threats to the river ecosystem. This study attempted to understand the patterns of avifaunal assemblage in the Bharathapuzha river basin which is highly disturbed due to anthropogenic pressures that destroyed the riverine habitats, water quality, and natural water flow.Item Ecology of elephants (Elephas maximus) and their interactions with humans in south West Bengal, India(SACON, 2023) Singh, Akriti; Kumara, H NThe thesis delves into the intricate dynamics surrounding the range expansion of Asian elephants in South West Bengal, catalyzing heightened human-elephant conflicts. It meticulously outlines the evolution of this phenomenon, starting from the elephants' modest presence in the 1950s to their expansive spread across 13200 km² by 2010–18. Through structured surveys and field observations, the elephants' footprint has been delineated across 163 grid cells in the region, showcasing their adaptability to varied habitat conditions. Central to understanding this expansion is the interplay between habitat factors and elephant presence. The thesis elucidates how the elephants' utilization of grid cells correlates positively with the forest edge, forest area, agricultural area, and barren land. As forests recede and agricultural land expands, elephants find themselves increasingly encroaching upon human settlements, leading to heightened conflict situations. Population estimation methodologies, ranging from dung count surveys to distance sampling, shed light on the elephant demographic in the region. However, the thesis highlights the challenges inherent in accurately gauging elephant numbers, particularly in areas where human activities disrupt their natural movement patterns. Despite these hurdles, the presence of a substantial number of immature elephants signifies a thriving population, albeit one grappling with human-induced disturbances. The thesis also sheds light to the ecological intricacies of elephant habitat use and feeding behavior. By overlaying grid cells on selected elephant habitats and analyzing geo-coordinates, the intensity of elephant habitat utilization was ascertained. The elephants' dietary preferences, encompassing a diverse array of wild plant species alongside agricultural crops, underscore their adaptive prowess in navigating human-altered landscapes. However, this dietary reliance on crops exacerbates conflicts, as elephants frequently venture into agricultural fields, triggering retaliatory measures from local communities.Item IMPACT OF THE WIND FARM ON SELECT FAUNAL COMPONENTS OF A DRY DECIDUOUS FOREST AT HARAPANAHALLI, DAVANGERE, KARNATAKA(SACON, 2021) V, Anoop; Arun, P RA global shift from conventional energy to the more environment-friendly and pollution-free renewable energy sources is increasingly evident in recent years. However, the renewable energy sources too have its own share of impacts on environment and life forms, although to a lesser extent compared to the conventional energy resources. The major future source for energy generation in India is expected to be the wind energy. The wind turbine installation started in India in 1984, however there are very few studies on the negative effect of wind turbines on the environment. The current pace of wind energy development in India poses questions about the extent of potential impacts by the wind farms on the environment. This study focused on the impacts of wind energy production on birds, bats, and black-naped hare (Lepus nigricollis) at Harapanahalli, Karnataka with the following objectives. (1) Study the Impacts of the wind farm on birds and bats of Hyrada reserve forest (2) Study the Impacts of wind farm on Black-naped (Lepus nigricollis) hare at Hyrada reserve forest. (3) Develop GIS-based model maps using distribution range information of select faunal species to evaluate the spatial variation in the impact potential of wind farm development.Item Assemblage of Shorebirds in the Sindhudurg District Maharashtra(SACON, 2022) Babu Rao, Golusu; Babu, SMigratory shorebirds are the most threatened waterbird species around the world. Shorebirds in India have received little attention, particularly on the west coast. Thus, this study was conducted in the coastal areas of the Sindhudurg district, Maharashtra. The coastal habitats in the district are dominated by beaches, mudflats, and mangroves, which have been identified as potential habitats for shorebirds. Thus, the distribution, abundance, and factors influencing habitat use of shorebirds were studied from these three habitats across seven sites and five seasons. Among the three habitat types, mudflat was an important area for shorebirds thus fine-scale habitat selection for select shorebird species was carried out in the mudflats. Total count and photographic methods were used to count the birds. A total of 36 species of shorebirds were recorded, of which 21 and 10 species used Sindhudurg coast as stopover and wintering sites respectively. Mudflats had a higher species richness (21) than the beach (20) and mangroves (14) habitats. Plovers were the most common and abundant species in the study area. nMDs showed various pattern of shorebird species composition across the habitats and seasons. The cluster analysis revealed five distinct migratory seasons in shorebirds along the Sindhudurg coast: 1) arrival phase, 2) wintering phase, 3) early departure and late arrival phase, 4) departure phase, and e) breeding phase. The physiochemical parameters of water and prey varied significantly between habitats and seasons. Salinity showed decreasing trend from beach (34.67±5.94) towards the mangroves (28.07±7.66). Prey abundance was higher in mudflats and during the wintering season. BIO-ENV analysis showed that among the measured environmental parameters salinity was the key factor influenced prey distribution (ρ=0.51). The shorebird richness (X2=56.5, P=0.00) and abundance (X2=32.6, P=0.00) positively influenced by crustacean density, salinity and bivalve density. Prey availability and accessibility had a major impact on the finescale habitat selection of the studied species. The Lesser Sand Plover and Kentish Plover avoided areas with oyster beds and preferred fine sand substrates with higher crab densities. Eurasian Curlew selected high profitable foraging sites close to the waterline with increased surface penetrabilityItem Feeding Ecology and Social Structure of Golden Langur (Trachypithecus geei) in Secondary Forests of Chakrashila Wildlife Sanctuary, Assam, India(SACON, 2021) Shil, Joydeep; Kumara, H NI studied Golden langurs in altered habitats to understand the consequences of habitat conditions on social organization, ecology and ranging pattern. I selected 12 groups inhabiting forest edge and forest core of Chakrashila Wildlife Sanctuary and the adjoining rubber plantation. Three groups from the different habitats were also selected for activity budgeting and ranging data collection. Instantaneous scan sampling method was used and groups were followed from dawn to dusk. Geocoordinates of the group movements were recorded at every 30 minutes interval. The overall group size of golden langur was 11.3±3.5SD, and ranged between 5 and 18. The mean group size in forest core, forest edge and rubber plantation differed significantly. Births occurred in all the months but peaked between May and September (82.6%). The mean number of births positively correlated with mean monthly rainfall. Diurnal activities varied significantly with highest time spent on resting followed by feeding, locomotion, monitoring and social for all the three groups. The core group, edge group and rubber group spent 27.33%, 26.83% and 25.27% time in feeding respectively. Food items consumed varied significantly across the seasons and across the groups with highest leaf consumption of leaf annually by core group (65.67%), edge group (59.39%) and rubber group (34.60%). Number of plant species consumed by core group, edge group and rubber group are 39, 41 and 40 respectively. Mean annual day path length among the three groups have significant difference (F2,182=11.08, p<0.001). Home range area used by core group, edge group and rubber group are respectively 29 ha, 42.25 ha and 49.5 ha, however, the spatial use of the habitats by each group varied seasonally. It therefore, appears that social organisation, activity budget, diet and ranging pattern are related to disturbance and environmental factors. The behavioural parameters may influence life-history traits if continuous habitat alteration persists.Item OCCUPANCY AND DISTRIBUTION PATTERN OF OWLS IN ANDAMAN ISLANDS WITH SPECIAL REFERENCE TO COMMUNITY ASSEMBLY RULES(SACON, 2021) Marimuthu, S Suresh; Babu, SThere is a laxity of knowledge in taxonomically well recognized species, which did not gain adequate attention from conservation biologists and are prone to extinction. Owls are one of such avian nocturnal predators. Due to their nocturnal and conspicuous behaviour many of the avian community studies neglecting owls to incorporate in them. Considering these facts, studies on owl species ecology is prerequisite for the conservation. So, this thesis is an attempt to develop such base line information on owls with two broad objectives: (1) to assess the relative abundance and occupancy of owls in the Andaman Islands and (2) to evaluate various species assembly rules in offshore islands using owls as model organism. To achieve these objectives, I did a survey with an aim to elucidate the environmental gradients (such as land-cover types, logging intensity) that influence the distribution and abundance of owls in the Andaman Islands. In addition, I also assessed the perception of local people about owls and effect of human activities on roosting owls using experimental and evidence-based study. I also employed Hierarchical multi-scale sampling strategy to estimate large-scale (sampling unit level - Ψ) and small-scale (survey station level - θ) occupancy using multi-detection methods (p). I modelled the occurrence of each species of owls as a function of island characteristics using the presence-absence of owls and a set of abiotic and biotic variables of 73 offshore islands. Finally, dispersal-driven assembly rules of the five owl species were tested with the same offshore islands surveyed. EcoSim v. 7.0 was used to test the Diamond’s assembly rules (1st, 2nd and 5th rules) using two statistical indices viz., C-score and number of unique species combinations. NeD and Nestedness Temperature Calculator were used to test nestedness. Overall, this study provided first-hand information about the owls’ distribution, their threat, ecological requirements, and the dispersal patterns in Andaman archipelago. It also helped to identify the critical island characteristics to ensure the avian population. The continued alteration of evergreen forests, extraction of minor products (for example: cane) and logging associated understory clearings might bring these endemic species’ survival to an end.