Theses and Dissertations

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Start date: 2020Subject: search.filters.subject.Species abundance

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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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    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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    Patterns of Mammalian assemblages in forested riverscape in Koyna Wildlife Sanctuary, the Northern Western Ghats, India.
    (Wildlife Institute of India, Dehradun, 2021) Jelil, Shah Nawaz; Ramesh; Hayward, Matt W.
    This study deals with understanding mammal abundance and habitat status in an altered watershed, a dammed river that now forms a part of the Koyna Wildlife Sanctuary, in the northern Western Ghats, Maharashtra, India. Study aimed to understand habitat status and mammal abundance along the stream network within upstream Koyna Reservoir, 55 years after its construction. By doing this, I aimed to understand and draw conclusions on generally how reservoirs are functioning as protected areas. This study is particularly relevant and important for the threatened and unique landscapes of the Western Ghats. A systematic conservation prioritization analysis was conducted to assess which areas within Koyna should be prioritized for effective allocation of management resources. Overall, using robust modelling approaches, the thesis reports about the present status of riparian forests and mammals using these riparian areas in Koyna Wildlife Sanctuary.
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    Seasonal Pattern in Habitat Selection by Birds of Jhimil Jheel Conservation Reserve Uttarakhand
    (Wildlife Institute of India, Dehradun, 2022) Das, Ankita; Ramesh, K.
    The present study was initiated to assess seasonal pattern in habitat selection by birds in Jhilmil Jheel Conservation Reserve (JJCR) which is a small-sized Protected Area (PA). This work also focuses on both ‘process’ and ‘pattern’ of bird community structure. The work also focusses on how small-sized PAs are equally important in conserving wildlife species such as birds. Understanding the relationship of birds with habitat provides insights into habitat use, which contributes in the conservation of species. Habitat selection of birds is one of the foremost steps to understand the complexity of their community. Some factors influencing habitat selection are habitat heterogeneity, structure and composition of vegetation, seasonality and co-occurrence. Habitat heterogeneity helps in maintaining high bird diversity. Abundance and distribution of species in a community also depends on the physiognomic, floristic composition of the forest vegetation and seasonality. For the present research work, the study area was stratified into six habitats: plantation, mixed deciduous forest (mixed forest), riverine habitat, scrub forest, grasslands and agriculture fields-human settlement.
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    Response of small carnivore community to landscape and climatic variability in the Great Himalayan National Park Conservation Area, the Western Himalaya
    (Wildlife Institute of India, Dehradun, 2022) Bandyopadhyay, Meghna; Ramesh, K
    This study will add knowledge about the elusive and lesser-known small carnivores in a gradient of disturbed and less disturbed habitats. Objectives The study focusses on the following objectives: 1) Occurrence and abundance estimation of small carnivores across space and time along the elevation gradient. 2) Assessment of community composition of small carnivores and association with other small carnivore species. 3) Evaluation of landscape sensitivity by representative small carnivore species. 4) Distribution modelling of indicator species to anthropogenic and climatic effects in the current context Study focusses on the arrangements of small carnivores along the elevation gradient in terms of site intensity usage and abundance of small carnivores. Marked (leopard cat) and unmarked (red fox) species were considered and statistical models were used to find the overall abundance and also across the elevation gradient in space and time. demonstrates the coexistence patterns of small carnivores (red fox and leopard cat) in three dimensions; space, time and diet. The niche dynamics was assessed and compared between low human disturbance and high human disturbance areas. Study reveals how the coexistence patterns of small carnivores change with differential human disturbances.
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    Understanding aspects of demography and resource partitioning mechanisms of large felids among with abundance and spatial distribution of prey in Similipal Tiger Reserve, Odisha
    (Wildlife Institute of India, Dehradun, 2024) Rathore, Harshvardhan Singh; Pandav, Bivash; Jhala, Y.V.
    This study investigates the crucial aspect of coexistence for large predators like tigers and leopards sharing the same landscape and delves into the population dynamics of these animals by identifying the mechanisms of resource partitioning. By acting as a window into the inner workings of the ecosystem, the study reveals how tiger and leopard populations function alongside each other. Identifying the factors that influence their ability to share the resources successfully is vital for developing more effective conservation strategies. This knowledge ultimately contributes to ensuring the long-term survival of both tigers and leopards in this landscape. A precise assessment of several demographic parameters is necessary to make informed management decisions for their conservation within this unique habitat. These parameters include population density, sex structure, recruitment, and survival rates. With this background, the study comes with the following objectives. (1) To assess the abundance and spatial distribution of prey in STR.(2) To assess the various demographic parameters of large felids (tiger and leopard) in STR. (3) To determine the mechanisms of resource partitioning of the tiger and the leopard in STR. Similipal Tiger Reserve is located in the Mayurbhanj district of Odisha, between86˚06' and 86˚36' East longitude and 21˚31' and 22˚02' North latitude. The study was carried out over three years (2019–2021) across eight ranges in the core area of STR: Chahala, Nawana North, Nawana South, and Pithabata South Wildlife in the northern core, and UBK, Jenabil, Bhanjabasa, and National Park in the southern core.
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    Assessing the effect of anthropogenic disturbance on epiphytes in Khasi Hills of Meghalaya, India
    (Wildlife Institute of India, Dehradun, 2024) Nongrang, Tiewlyngksiar Lyngdoh; Kumar, Amit
    The key findings emerged from this study include- A total of 66 epiphytes comprising 32 species of orchids, 09 species of ferns, and 25 species of hemi-epiphytes & holo-epiphytes were recorded from the study area. Orchids had the highest species richness followed by ferns and hemi-epiphytes & holoepiphytes. Among orchids, species of Bulbophyllum, Pholidota and and a were dominant. The dominant species among ferns included Lepisorus sp., Davallodes hymenophylloides and Pyrrosia flocculosa whereas, among hemi-epiphytes and holo-epiphytes, the dominant species were Piper longum, Pothos chinensis, Rhaphidophora decursiva, Scurrula parasitica and Ficus sp. The abundance of epiphytes was observed highest in the Private Forest followed by the Village Forest and Reserve Forest. Species richness, using sampled-based Rarefaction curves of epiphytes showed that the curve is not reaching an asymptote and observed species were highest in the Village Forest followed by Reserve Forest and Private Forest. The most abundant groups of epiphytes in Private Forest were hemiepiphytes mainly dominating on the lower trunk. In the village forest, orchids were found occupying the inner canopy. In Reserve Forest, ferns were in abundance and occupied the upper trunk. Species correlation shows no difference in species composition. Environmental variables are factors that can explain the difference in species richness and abundance of epiphytes.
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    Abundance and social organization of male Asian elephants (Elephas maximus) in Rajaji Tiger Reserve
    (Wildlife Institute of India, Dehradun, 2024) Madhusudanan, Abhimanyu; Pandav, Bivash; Lakshminarayan, N.; Mondol, Samrat
    1. Asian Elephants are complex, social, and polygynous mammals living in fission-fusion societies. Male elephants are known to alternate between leading solitary lives, in all-male groups or associating with mixed-sex herds. All-male groups allow younger males to learn from older males, test strengths and spar with their peers. While much work has been done on female Asian elephant societies, studies focused on male association patterns are limited, but gaining importance in the light of human-elephant conflicts. In this study, I estimated the abundance of adult male elephants in a stretch of forest spanning over 40 km along the east bank of the river Ganga in Uttarakhand using a polygon search-based spatially explicit capture recapture (SECR) framework 2. I invested a survey effort of ~3014 km to estimate the abundance of the adult male segment of the population using a capture-recapture framework. Using a combination of morphological features, I identified 34 adult males from 124 elephant sightings. Association patterns of the male elephants, following behavioural sampling approaches were also recorded during the surveys. 3. Adult male elephant density was 0.05 (SE=0.01)/km2, and a derived abundance of 40 (SE=1.4) for the 475 km2 study area. This demonstrates that polygon search-based SECR is an effective approach in estimating elephant abundance.
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    Responses of Wild Ungulates to Anthropogenic Pressure and Perception of Local Communities Towards Conservation of Wild Ungulates in Dampa Tiger Reserve, Mizoram India
    (Wildlife Institute of India, Dehradun, 2021) Chakama, Joonu; Sathyakumar, S.; Kawlni, Lallaianpuii; Kolipakam, Vishnupriya
    With the increasing anthropogenic pressures, conservation of ungulates is ever more crucial as they help in maintaining the forest structure. The impact of anthropogenic pressures such as hunting of wild ungulates by local communities in Mizoram, India, is limited and lacks reliable information. This study was conducted in Dampa Tiger Reserve (DTR), Mamit district, Mizoram from January-Mid May, 2021 to quantify the responses of wild ungulates to the anthropogenic pressures, as a measure of conservation efforts. This study focussed on the population and distribution of ungulates in Dampa Tiger Reserve (DTR), Mizoram and assessed how the ungulates responded to human use areas. Stratified systematic sampling was done in an intensive study area (40 km2) to assess the ungulate density, distribution and activity pattern. In addition to that, the perception and attitude of local communities towards wild ungulates were also assessed. Estimates of the distribution, population and activity pattern of ungulates were obtained using single season occupancy model and cameratrap based distance sampling method whereas the local people perception and attitude were analysed based on answers from the semi-structured interview. The study was carried out on the Teirei and Phuldungsei range of the DTR. A total of 40 grids (1 km2 each) were sampled following the above framework. The grids were sampled using Camera-based distance sampling for population estimation in which the cameras were placed at the centroid of the grid. The density of the ungulates in two areas (high and low human use) could not be compared as the anthropogenic disturbance was homogenous throughout the study area. However, the pooled density of wild pig (0.55±0.23) was the highest among the other species, followed by barking deer (0.28±0.06) and sambar (0.20±0.09). The activities of the ungulates were at the peak from the crepuscular period to early morning and late evening. Occupancy pattern showed that barking deer distribution was influenced by the food availability/ground cover including areas near human habitations whereas sambar occurrence was negatively influenced by non-forest and presence of anthropogenic disturbance. Perception survey revealed that villagers showed positive perception towards ungulate conservation, however, in contrast to these responses, conservation practices in DTR by the local communities still lacks as intensive hunting still prevails. This study highlights the impact of anthropogenic pressure towards ungulates and how strengthen management interventions is necessary to ensure the conservation of ungulates in DTR.
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    Influence of Forest Cover on Fruit and Frugivore Richness and Abundance in Southern Western Ghats
    (Wildlife Institute of India, Dehradun, 2021) Takorbhai, Patel Zankhnaben; Page, Navendu V.; Kumar, Amit
    Habitat fragmentation is a pervasive threat to ecosystem processes like seed dispersal, which is vital for biodiversity maintenance in tropical forests. Habitat fragmentation negatively impacts the richness, abundance and composition of plants and animals, thereby disrupting the interactions between them, with cascading impacts on biodiversity. However, the remnant fragments continue to harbour biodiversity. However, it is critical to determine the functional value of the fragments in terms of fruit resource diversity and availability and prevalence of frugivores across different size classes. To this end, I conducted the study in the Valparai plateau and adjacent contiguous patches of rainforests in the Western Ghats. I first determined the organization of plant-seed disperser community and identified key frugivores and plants in the landscape using network analysis. Using mixed models and the recently developed Joint Species Distribution Modelling approach called HMSC (hierarchical modelling of species communities), I investigated 1) the relationship between the amount of forest cover and richness of fruiting plants across different seed size classes, 2) the relationship between the amount of forest cover and availability of fruit s across different seed size classes 3) the relationship between richness and presence of all the avian frugivores and, amount of forest cover, and richness and availability of fruits. I recorded the frugivores and fruiting plants from 33 trails distributed in 12 fragments and 2 sites in contiguous area during four months of sampling. I also recorded plant-frugivore interactions. I documented 49 species of fruiting plants and 17 species of avian frugivores