Theses and Dissertations

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Start date: 2020Subject: search.filters.subject.Habitat use

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    Assessing Ghost crab distribution, abundance and habitat use along the Coromandel Coast, Tamil Nadu
    (Wildlife Institute of India, Dehradun, 2025) Keerthi V; Gopi, G.V.
    Sandy beach ecosystems around the world are facing numerous threats and tremendous pressure due to ever increasing human population. One such threat, relevant to the Indian coastline, is the large scale plantations of shelterbelts of the exotic pine, Casuarina equisetifolia, which alters beach geomorphology. The effects of such plantations on permanent shore-dwelling organisms are poorly studied. Hence Ocypode crabs, the most conspicuous macro-invertebrate on sandy beaches, has been used as a model taxon to study the effects of different kinds of inland vegetation (Casuarina plantations, Mangrove plantations, native dune vegetation) on beach geomorphology and consequently, shore dwelling ghost crabs. The present study aims to - (1) Assess the density, distribution and demography of ghost crabs across treatments (2) Understand variations in habitat use and burrow architecture across treatments (3) Understand the effects of inland vegetation on beach geomorphology 2. A total of 24 transects, temporally replicated thrice each month between January 2025 - April 2025, were walked to estimate densities of ghost crabs using burrow counts as a proxy. 87 burrows across the treatments were cast using a mixture of Plaster of Paris and water and traits such as depth, diameter, shape and branching patterns were studied. Coast characteristics like slope, compactness, beach width, moisture and temperature were recorded at each study site. 3. Mean burrow densities and across shore distribution of Ocypode ceratophthalmus differed across the treatment types, with lowest densities in beaches adjacent to Casuarina plantations. This however wasn't statistically significant. The burrow structures also differed in complexity across treatments with the major drivers for this 7 difference being the size of the crab and the type of inland vegetation. Environmental variables were not found to have significant effects on burrow architecture. 4. The results indicate that the type of inland vegetation affects the population of ghost crabs through changes in beach geomorphology. Ghost crabs were also found to modify the structure of their burrows with changes in the habitat quality and environmental conditions, which gives insights into their adaptive capacities. The study, thus raises questions on the effects of certain management interventions, like the planting of shelterbelts on habitat quality and on the ecology of the species dwelling in the said habitats.
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    Assessing Habitat Use and Activity Pattern of Hoolock Gibbons (Hoolock hoolock) in the Mosaic Landscape of Garo Hills
    (Wildlife Institute of India, Dehradun, 2025) Passah, Betwonsaoo; Lyngdoh, Salvador; Kumara, H.N.
    Primates react to environmental disruption in a variety of ways. Their home range and activity pattern are often linked with anthropogenic disturbance of the landscape. This study focuses on Hoolock Gibbons (Hoolock hoolock) in Garo Hills, Meghalaya, which is a highly arboreal primate and the only ape in India. Hoolock gibbon’s habitat in the Garo hills is being degraded due to the increase in the conversion of forest land into plantations. As most of these forests where the gibbons are located are managed by the community, these forests face overexploitation, which threatens the endangered Hoolock Gibbons habitat. This study aims to establish a baseline Hoolock Gibbon Ecology in the community-managed forest and protected area in the mosaic landscape of Garo Hills, Meghalaya, by examining their habitat use and activity pattern. The main objective is to determine the Gibbon's habitat use within its home range and examine their activity patterns in different forest types. The study is conducted in Daribokgre CR (a continuous forest patch adjoining Nokrek National Park), Dura Kalakgre CR (a small strip of CR which is surrounded by abandoned jhum and active jhum), and an Areca nut plantation which is located in Rensengre close to Selbalgre CR. In each area, one group is chosen and tracked for 20 days. Geo-coordinates and behavioural data were collected, with vegetation sampling and disturbances within a 1 ha cell size grid, which was overlaid on the location points. QGIS was used to map habitat use based on the geospatial data, and the Generalised Linear Model (GLM) was used to check the influencing factors. The activity budget was calculated to understand the behaviour patterns. Across the three studied groups, the habitat types were different group in Daribokgre (Forest group) is dominated by forest patches, the group in Dura Kalkgre (Jhum group) was dominated by abandoned jhum, and the group in Rensengre (Plantation group) was dominated by plantation, and their home range size were 24 hectares, 30 hectares, and 23 hectares, respectively. GLM reveals a significant effect only for the group in the disturbed habitat on the intensity of use. Overall, habitat use patterns and activity patterns varied across the groups, reflecting in behavioural and habitat preference.
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    Estimating Abundance, Habitat Use, and Acoustic Characteristics of Irrawaddy Dolphins (Orcaella brevirostris) in Chilika Lagoon
    (Wildlife Institute of India, Dehradun, 2025) Sakshi; Kolipakam, Vishnupriya; Gopi, G.V.
    This study provides a comprehensive assessment of the Endangered Irrawaddy dolphin (Orcaella brevirostris) in Chilika Lagoon, India, through an integrated approach combining visual and acoustic surveys, environmental modelling, and prey availability analysis. Visual line-transect surveys and passive acoustic monitoring (using FPODs) were used to estimate dolphin abundance and explore patterns of habitat use. Dive-time observations revealed that calves and non-calves differ in their diving behavior, with non-calves exhibiting longer and more variable dive durations. Mark-recapture analysis produced corrected abundance estimates ranging from 24 to 32 individuals, with variation influenced by observer mismatches and brief surfacing events. To assess prey availability, catch per unit effort (CPUE) surveys were conducted at 22 sites in collaboration with local fishers. The highest CPUE values were recorded in the high salinity area (Outer channel) and low salinity area (Northern sector), indicating these areas may offer better foraging opportunities. Prey community sampling across 11 sites revealed spatial differences in species richness and evenness, with some locations dominated by a few taxa and others exhibiting high diversity. Richness estimators suggested that the true species count exceeds what was observed, indicating under-sampling in certain areas. Environmental modelling using a negative binomial generalized linear model showed that salinity had a significant negative effect on dolphin acoustic detections, while dissolved oxygen and depth were positively associated but not statistically significant. The frequency ranged from 20 kHz to 200kHz with a median frequency of 98kHz. The interclick interval ranged from 850 millisecond to 1010865 milliseconds with a median of 23605 millisecond. The histogram for ICI displayed a positively skewed distribution, consistent with irregular click trains interspersed with longer pauses. The findings highlight the importance of salinity and prey availability in shaping dolphin distribution in Chilika Lagoon. The results support targeted conservation actions such as regulating freshwater inflow, protecting productive foraging zones, and expanding acoustic monitoring efforts to improve long-term management of this vulnerable population.
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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.
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    The Spatial Ecology and Conservation of Seagrasses of the Gulf of Kachchh, Gujarat
    (Wildlife Institute of India, Dehradun, 2024) Pathan, Sameeha Vahedkhan; Sivakumar, K.
    Seagrass ecosystems provide ecosystem services that rank among the highest in economic valuation worldwide. They also provide a range of economic, social, and environmental goods and services, which greatly increase coastal communities' resilience to the impacts of climate change. As unique marine habitats, seagrass ecosystems provide shelter and food for marine species during different life stages and contribute to sediment accretion and primary production. The high diversity of marine plant and animal life supports tourism activities and provides the raw materials for medicinal, agricultural, and structural applications. Furthermore, the physical structure of seagrass ecosystems attenuates wave height and speed, protecting coastlines from erosion and storm surges. Threats to seagrass ecosystems in the coastal areas of the Gulf of Kachchh include pollution, rising sea levels, eutrophication, reduction of light intensity and die-back. These all negatively impact seagrass ecosystems, such as increasing growth of epiphytes, sediment anoxia, or increased prevalence of diseases. Further, the effects of climate change on seagrass ecosystems will be additional stressors. The underlying factors affecting seagrass ecosystems are direct human pressures such as pollution, disturbances, and eutrophication. The combined stressors – human pressures and climate change impacts – are likely to exceed the thresholds for seagrasses, leading to, among other things, i) redistribution (reduction and coastal migration) of existing habitats and ii) widespread seagrass ecosystem die-off. In this context, this study was conducted between January 2018- March 2022 and aimed to understand the phenology, biomass and spatial distribution patterns of seagrasses of the GoK, using which I attempted to understand the foraging behaviour, habitat use and movement ecology of dugongs in the Gulf of Kachchh. The major objectives of the study include a) Mapping the distributional characteristics and patterns of seagrass meadows in the southwestern GoK, b) understanding the seasonal variations in the abundance of seagrasses on topographically distinct meadows, c) investigating fine-scale and topographical determinants of dugong habitat preferences and d) to assess the role of semi-diurnal tides' influence on dugong foraging habitats.
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    Resource partitioning of non-pantherine carnivore community in Kanha Tiger Reserve, M.P., India.
    (Wildlife Institute of India, Dehradun, 2022) Pradhan, Anup Kumar; Jhala, Y.V.; Qureshi, Qamar
    Carnivores of all groups have unequivocal role in structuring and functioning of their ecosystems. Hence their existence need to be secured to maintain functional ecosystems. In the current scenario of rapid industrial growth and economic development, pressure on natural resources is escalating, which in turn has jeopardized the survival of important species. Hence, to maintain harmony between economic growth and ecological balance, an effective wildlife conservation and management plan should be a priority. The Kanha Tiger Reserve (KTR), spreading over an area of around 2100 km2 located in the central Indian highlands, has immense ecological significance as it supports a wide variety of flora and fauna. The tiger reserve is home to carnivores, including tiger, leopard, dhole, sloth bear, and many small cats. However, there are several conservation challenges exists for the persistence of this ecosystem. A thorough understanding of the ecosystem and its inclusive components is a prerequisite for developing and implementing an effective wildlife conservation plan. And in the case of KTR, despite several pioneer studies, the existing research gap on the ecology of small and meso-carnivores undermines the understanding of the complete ecological functioning. To fill this research gap, I undertook this study focusing on distribution, habitat use and preference of small and meso-carnivores in KTR. I aimed to study the distribution pattern and abundance of non-pantherine carnivores (Sloth Bear, Wild Dog, Jackal and jungle cat) and their niche separation by developing a species distribution and habitat suitability map. I performed camera trapping exercises during three successive seasons in 2014, 2015, and 2016 successively in all the available habitat types to obtain information on the abundance and distribution pattern of the targeted species. The camera traps were placed in a two sq km grid-based manner. I used data from transect surveys, remote sensing techniques and published literature to obtain other ecological variables. I used presence software to run the occupancy model for each focal species separately, considering relevant environmental variables. Similarly, I used the Maxent software to prepare the habitat suitability map for each species individually. I used the kernel density approach in R software to analyze the activity overlaps between these studied species. As a result of occupancy analysis, tiger, leopard, sloth bear, and jungle cats were observed to be inhabited in the cores area of the tiger reserve and associated with dense forest cover, grasslands, and prey abundance. However, dholes preferred the fringe area of the forest, associated negatively with densities of tigers, leopard, and their preferred area, i.e., the core of the forest and positively with the grasslands. In addition, variables such as distance from human settlements, terrain ruggedness, and NDVI also affected the occupancy of these study species in the KTR. Jackal did not follow any particular pattern rather it observed throughout the forest area. Aligning with the occupancy result, the habitat suitability maps prepared by the Maxent model strengthened the observation of the spatial ecology of these carnivore groups in the KTR. The Maxent model showed that the large carnivores at the ecosystem's apex position preferred to live in the core area of the forest with abundant prey and least human interference. However, second and third order carnivores such as dholes, preferred to live outside the core to avoid possible strife with the dominant tiger and leopard. The habitat selection by these meso carnivores also indicates the dominancy iii of the large carnivores in occupying the central position and their influence in the placement of the subordinate group of carnivores in a common ecosystem. We did not observe any effect of tiger and leopard on the habitat preference of sloth bear and jungle cat which indicated the difference in the dietary pattern also play significant role in occurrence of these sympatric carnivores in a multi-predator ecosystem. Tigers and leopards were primarily crepuscular and nocturnal. Despite high activity overlap, their activity peaks were different from each other. Dholes and jackals were active during the day, whereas Sloth bears and jungle cats were nocturnal. The results of temporal interaction among these carnivores were not completely diverged from the pattern of spatial interactions observed earlier. Instead, these results strengthen the findings of the spatial interaction among these carnivores in the KTR. As observed earlier, dholes and jackals shift their activity to avoid possible conflict and become diurnal. In contrast, the activity pattern of tigers and leopards did not influence the activity pattern of sloth bears and jungle cats. The study provides information on the spatiotemporal interactions of a carnivore community in a multi-predator ecosystem in central India. The findings strengthen the earlier understanding of the ecology of large-bodied carnivores such as tigers and leopards. At the same time, it enhances the knowledge of their counterpart i.e. the lesser studies small and meso- carnivores of KTR. Large-bodied carnivores occupied the central and apex position of the ecosystem and regulated the distribution pattern of the meso-carnivores present in their ecosystem. However, species with a different ecological niche were less influenced by these apex predators.
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    Exploring ecological separation between Himalayan blue sheep and Himalayan ibex during winter in Indian Trans-Himalaya
    (Wildlife Institute of India, Dehradun, 2024) Prakruthi, G.M.; Sathyakumar, S.; Lyngdoh, Salvador; Bhatnagar, Yashveer
    According to resource selection theory, two related species with similar ecological requirements compete for the same resources. They can only coexist if they are ecologically separated, either by habitat or food preference. This study explored the resource use and ecological separation of ibex (Capra sibirica himalayanus) and blue sheep (Pseudois nayaur) during the winter in the Spiti Valley, focusing on their segregation in space, habitat use patterns, diet, and activity pattern. The study was conducted in Kibber and Chicham areas (57 km2) of Kibber Wildlife Sanctuary, Himachal Pradesh, India. This study slightly deviates from the findings of a previous study by Namgail (2006), which reveals a high overlap in the habitat use between ibex and blue sheep in the Zanskar mountains. Systematic sampling using transects and trails, vantage points, opportunistic sampling, and camera traps was employed. Habitat and vegetation variables were recorded at random points and animal sightings to understand the patterns of habitat use and food selection. Spatial and temporal overlaps were analysed and micro-histological analysis of faecal samples compared the proportions of monocots and dicots in their diets. The study investigated how ungulates utilize habitats and their dietary habits with the availability of resources in their environment. Results showed substantial overlap in activity patterns, with the Jaccard similarity index indicating less spatial overlap between the species. The generalized linear model and Non-metric dimensional analysis indicated segregation based on their habitat preferences. However, there were no significant differences in their diets, the two species differed in the use of habitat at finer scales. Ibex preferred interspersed rocky slopes and slabs because of high rocky areas (escape terrain) and sparse vegetation, trading food for security. Blue sheep preferred less rocky areas with high vegetation cover like smooth slopes. Ibex preferred areas with more escape routes available than blue sheep. Thus, I conclude that Blue sheep, being more abundant than ibex, occupy distinct regions within the study area, and have a competitive advantage. While ibex are present in smaller numbers and confined to a specific region. Understanding their ecological requirements, especially in harsh winters, is crucial for targeted conservation efforts to ensure the sustainability of these species in a rapidly changing environment. Future research should focus on climate change impacts on habitat use and resource availability
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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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    Factors influencing the habitat use of owls in a mosaic landscape in Garo Hills, Meghalaya
    (SACON, 2020) SAILAS, S. SANGEETH; Pramod, P; Babu, S
    Habitat use of owls is under-studied in the tropics, and more so in North-eastern India, a part of the Indo-Burma region, one of the biodiversity hotspots of the world. Twenty species of owls have been recorded in North-eastern India, and yet there have not been much studies on any of them from the region. Hence, a study on the habitat use of owls was conceived, selecting the Garo Hills in Meghalaya as the study site, where the landscape is a mosaic made up of plantations, agricultural fields, settlements, disturbed and undisturbed forests. The presence of Community Reserves, a type of Community Conserved Area, adds to the heterogeneity in the landscape.
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    Comparative Analysis of Abundance Estimation Methods for Ungulates Along with their Spatio-Temporal Interaction and Habitat use in Pakke Tiger Reserve, Anunachal Pradesh
    (Wildlife Institute of India, Dehradun, 2021) Singh, Tarun; Kolipakam, Vishnupriya; Qureshi, Qamar; Sathyakumar, S.
    Abundance estimation and habitat utilization of species are critical for the conservation of any species. The forests of North-Eastern India are challenging due to the low abundance of ungulates, dense undergrowth, and logistic feasibility. In this study, we attempt to use camera trap-based methods (distance sampling and random encounter model) to estimate the abundance and habitat use of five ungulate species in the Pakke Tiger Reserve of western Arunachal Pradesh. This study was conducted from February 2021 to May 2021.This study provides crucial information on abundances and habitat use, which can be used for focussed conservation efforts for ungulates occurring in low densities.