Theses and Dissertations
Permanent URI for this communityhttp://192.168.202.180:4000/handle/123456789/1
Browse
8 results
Search Results
Item Influence of Canopy Gaps on Mangrove vegetation and Crab communities in the Andaman Islands(Wildlife Institute of India, Dehradun, 2025) Sengannan, Perarivalan; Prabhakar, N.Small-scale, infrequent disturbances enhance habitat heterogeneity in the landscape and promote diversity. Canopy disturbances caused by lightning strikes in mature mangrove stands modify environmental factors such as canopy cover and light intensity. Response of mangrove vegetation and crab communities to such canopy gap formation remains the least investigated aspect among ecologists. The canopy gaps were stratified based on the recent and recovering status of vegetation recruitment along with gap age, and an intact forest plot was sampled as a control treatment. The result shows that canopy opening has a significant effect on water temperature, and it has a profound influence on structuring vegetation and the crab communities in mangroves. Seedling and sapling density was 2-fold higher in canopy gaps than intact forest, and higher sapling survival was witnessed in canopy gaps. 28 species of crabs were recorded collectively from all treatments. Crabs of the family Ocypodidae were found in large proportion in canopy gaps, as the organic matter from microalgae and bacteria is their primary food base. Overall, canopy gaps in contiguous mangrove habitats are a hot spot for crab diversity and serve as a regeneration niche for seedlings and saplings by creating structural heterogeneity in the landscape. It suggests that small-scale natural disturbances, such as canopy gaps, promote habitat complexity and crab diversity.Item Patterns of Ant Species Richness and Composition in Deccan Inselberg-Matrix systems of Karnataka(Wildlife Institute of India, Dehradun, 2025) Sujay G; Adhikari, B.S.My study looked into patterns of ant species richness and composition of Deccan inselbergs and surrounding human altered matrix (natural habitat, mango plantation) in Ramanagara taluk, Karnataka, in a bid to recognize their ecological and conservation potential. Ants were chosen as the model taxa, due to their micro-habitat specificity, to better understand environmental gradients and related faunal associations at different scales. Pitfall traps were used as the sampling methodology for ants, and habitat variables were collected at each trap; ants were identified until morphospecies level within respective genera. Data analysis included understanding habitat differences, patterns of species richness and composition, and relating these aspects. The results showed that inselbergs were distinct in terms of habitat structure as compared to the matrix, with the latter showing less vegetation complexity (lesser in mango plantation). While matrix and inselberg showed comparable levels of ant richness, delving deeper it was seen that natural habitat within matrix showed significantly higher richness as compared to the species poor, uneven mango plantation ant assemblage. Similarly, inselbergs and matrix showed similar average composition of their respective ant communities. However closer inspection showed that natural habitat and plantation, when compared separately with inselbergs, showed compositional dissimilarity to greater magnitude. Habitat variables, while statistically significant in their relationship with patterns of ant composition and richness at finer scales, explained a minimal amount of total variation seen in both. Inselbergs, as understood through this study, are not “barren wastelands”, but on the contrary are important reservoirs of regional diversity. In light of rapid human alteration of the surrounding matrix and threats like quarrying, invasive species, inselbergs and the low lying natural habitat need to be given greater conservation importance. This study is hopefully just one of many that are required to further assess the conservation and ecological potential of these amazing ecosystems.Item Ecology of Seagrass Habitats and its associated macrobenthic invertebrates in Andaman islands, India(Wildlife Institute of India, Dehradun, 2024) Gole, Swapnali; Sivakumar, K.; Johnson, J.A.; Das, HimansuThe diversity, composition, and growth of species in plant communities are shaped mainly by their complex interactions with local environmental settings. Owing to the unprecedented global decline of seagrasses, it is crucial to understand in-situ ecological interactions for informing mitigation measures. However, several ecological aspects of seagrass ecosystems are under-studied in the tropical Indian waters, which fall in the highly productive Indo-Pacific seagrass distribution bioregion, offering many socio-ecological services. In this context, my study aimed to address the ecological gaps in India's unique seagrass biodiversity hotspot, the insular archipelago called the Andaman and Nicobar Islands (ANI). Objectives of the study were 1) To assess the spatial distribution patterns of seagrass habitats and associated macrobenthic invertebrates in the Andaman Islands, 2) To understand the seasonal variation in seagrass meadows and associated macrobenthic invertebrates, 3) To understand the structural diversity of seagrass meadows and its influence on associated macrobenthic invertebrates, and 4) To document the Traditional Ecological Knowledge on seagrass habitats. The field study was carried out between 2018 and 2022, with a significant sampling period between January and May, as it is the best feasible season for fieldwork in ANI. The spatial diversity, distribution, and growth of seagrasses in the present study were primarily governed by the water depth, habitat heterogeneity, substrate types, and availability. The study suggests that any alterations in the benthic habitat profile of these meadows are likely to affect the species distribution patterns and overall ecological services offeredItem Ecological assessment of geometridae Moths (lepidoptera: Heterocera) along alitutudinal gradient in Dhauladhar Mountain range in Kangra (North Western) and Lahaul and Spiti (Trans-Himalaya) regions of Himachal Pradesh(Wildlife Institute of India, Dehradun, 2024) Kumari, Shabnam; Uniyal, V.P.; Chandra, KailashThis study investigates the ecology (diversity and distribution patterns) of Geometridae moths across the altitudinal gradients of the Himalayan and Tran Himalayan regions in Himachal Pradesh. Geometridae moths are the famous insect herbivore surrogate taxa. They have been studied globally across different mountain systems. Through the documentation of species diversity, and the analysis of ecological patterns associated with these moths, this study aimed to contribute towards a better understanding of biodiversity dynamics in the Himalayan region. The research findings hold significant implications as a comprehensive baseline information on the species diversity and community dynamics of Geometridae moths in the region along with insights from the zoogeographic analysis. It also highlights future research needs and conservation concerns in light of the impacts of climate change and human-driven changes in land-use patterns in the region. objectives proposed for this study were i) to study the diversity and species richness patterns of Geometridae moths along the altitudinal gradient of the Dhauladhar Mountain Range (DMR) (within the administrative boundary of the district Kangra), ii) to identify the potential indicator species of Geometridae moths for different habitat types (altitude) and environmental variables affecting their distribution and iii) assessment of the high-altitude Geometrid moth assemblage of Trans Himalaya (Lahaul and Spiti) region of Himachal Pradesh. The study was undertaken across the altitudes of the DMR and Lahaul and Spiti Valleys (LSVs) representing the Himalayan and Trans Himalayan biogeographic zones of India in Himachal Pradesh respectively. Species with strong preferences for specific altitudinal zones and forest types have the potential to serve as indicator species for long-term monitoring of climate change, habitat quality, and land-use changes in these regions. These findings provide valuable insights into our understanding of the biodiversity patterns and community characteristics of Geometridae moths across altitudinal gradients and different forest types in the regionsItem Landscape-level assessment of select group of pollinators and factors influencing their diversity and distribution in Kullu Valley, Himachal Pradesh.(Wildlife Institute of India, Dehradun, 2024) Khan, Sushmita; Uniyal, V.P.; Ramesh, K.Change detection analysis using satellite data in a remote sensing platform is a crucial tool for understanding shifts in land use and land cover (LULC) over time, allowing for the identification of environmental and human-induced changes across various spatial and temporal scales. This method aids in assessing the impact of factors like urban expansion, agricultural practices, deforestation, and climate change on biodiversity and ecosystems. Climate change, particularly in vulnerable regions like the Himalayas, poses significant threats to ecosystem services and biodiversity. This study explores the impact of LULC and climate change on pollinator diversity and distributional patterns in the Kullu and Tirthan valleys of Himachal Pradesh. By compiling a comprehensive list of entomofauna pollinators across various orchards in different landscape configurations, the research aims to emphasize the need of conserving pollinator species in this ecologically sensitive region. Additionally, the study predicts potential shifts in pollinator distribution under future climate scenarios, providing valuable insights for conservation strategies. Through systematic analysis, the research contributes to a deeper understanding of pollinator communities and their interactions within the mountain horticultural belt of the Indian Himalayan Region. Ultimately, the findings aim to inform targeted conservation efforts to preserve the rich biodiversity of pollinators in this area. The research focuses on two major valleys within the Kullu district, each presenting contrasting landscapes and ecological contexts. The Kullu valley, a 76 kms long stretch situated along the Beas river, is characterized by diverse land use patterns and heightened anthropogenic activity, particularly in horticulture and tourism. In contrast, the Tirthan valley, nestled along the Tirthan river for a 45 kms long stretch, is designated as a conservation area with minimal disturbance and dense forest cover. The study meticulously investigated pollinator diversity dynamics in the Kullu and Tirthan valleys. The study conducted in the Kullu Valley aimed to analyze land use changes over time using Landsat satellite imagery from 2000 and 2022. High-quality images with minimal cloud cover were obtained for both years, ensuring accurate analysis With the aforesaid aim in focus, I have tried to address the following three objectives in my thesis: Objective 1: To assess the change in landscape composition of the study area over time.• Objective 2: To assess the effect of change in landscape configuration and horticultural practices on pollinator communities (diversity and abundance) and their services. • Objective 3: To model the distribution of major pollinators of economic importance belonging to different groups (Hymenoptera, Lepidoptera, Coleoptera, Diptera) in the study area.Item Assessing the effect of anthropogenic disturbance on epiphytes in Khasi Hills of Meghalaya, India(Wildlife Institute of India, Dehradun, 2024) Nongrang, Tiewlyngksiar Lyngdoh; Kumar, AmitThe 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.Item Effects of Local- and Landscape-level Drivers in Influencing Bird Diversity and Persistence in Cashew Plantations of the Northern Western Ghats(Wildlife Institute of India, Dehradun, 2024) Madhu, Nandita; Jayapal, Rajah; Page, Navendu V.; Naniwadekar, RohitAgricultural expansion is a significant driver of deforestation and biodiversity loss, particularly in the tropics. The Western Ghats-Sri Lanka biodiversity hotspot is no exception. Most forest patches in the northern Western Ghats are being cleared for cashew cultivation. However, here, cashew plantations host varying proportions of cashew and native trees and have varying extents of ambient forest cover. Investigating the effects of such local and landscape-level drivers across land use types on taxonomic, functional, and phylogenetic diversities, as well as species- and trait-specific responses of birds, as implemented in this study, can give comprehensive insights on the impacts of forest conversion. I conducted this study in the low-elevation forests and cashew plantation landscape of Tillari, Maharashtra. I compared tree species diversity and vegetation structural attributes across land use types using Hill-Shannon diversity and linear models (LMs). To assess how land use type affects bird species composition and taxonomic diversity, I used non-metric multidimensional sampling (NMDS) and Hill-Shannon diversity. To compare functional and phylogenetic impacts across land use types, I used SES (Standardised Effect Size) values of fMPD (functional Mean Pairwise Distance) and pMPD (phylogenetic Mean Pairwise Distance) for LMs and Tukey’s post-hoc analysis. Using Hierarchical Modelling of Species Communities (HMSC), I looked for 1) bird species responses, 2) trait responses, and 3) a phylogenetic signal in the residuals. I collected bird and vegetation data from 100 points distributed across forest, mixed cashew plantations, and pure cashew plantations. My field collaborator (Vishal Sadekar) and I sampled vegetation within a 10 m radius of circular plots around all points. We sampled birds, implementing 10-minute point counts at a point, replicated 5 times across 4 months between January to May 2024. Vegetation differed significantly across all three land use types in terms of tree species diversity and tree height, where the forest had the highest estimates followed by mixed cashew. NMDS showed that the community in mixed cashew plantations overlapped with that of pure cashew plantations. There was no significant effect of land use type on functional diversity. But taxonomic and phylogenetic diversities were lowest in pure cashew. The HMSC model revealed a low explained variation (Tjur R2 = 0.1372), but I found land use type, a site-level variable, to exhibit the highest explained variation of 58% compared to the landscape-level variables. Forest species like Malabar Trogon (Harpactes fasciatus) and Black-naped Monarch (Hypothymis azurea) responded negatively to mixed and pure cashew plantations. Species like Golden-fronted Leafbird (Chloropsis auriforns) and Tickell’s Blue Flycatcher (Cyornis tickelliae) benefitted from mixed cashew and open country species like Indian Peafowl (Pavo cristatus) and Plain Prinia (Prinia inornata) responded positively to pure cashew. Trait response analysis revealed that evergreen species responded positively to the forest and negatively to both cashew habitats. Sedentary species responded positively to forest cover in 800 m. No evidence of a phylogenetic signal was found in the residuals (⍴ = 0.23, 95% CI: 0 - 0.68). This study highlights the value of mixed cashew plantations which are more habitable than pure cashew plantations due to native tree prevalence. However, this study also emphasises that even mixed cashew plantations cannot replace forests as habitats for evergreen forest species. This message is now more crucial than ever in the light of ongoing forest clearance in the northern Western Ghats.Item Assessing the distribution and density of the Fishing Cat in Bhitarkanika mangroves of eastern India by(Wildlife Institute of India, Dehradun, 2024) Ashik, C.S.; Mukherjee, Shomita; Gopi, G.V.; Pandav, BivashIdentifying the areas of occurrence, population, and the factors affecting the species distribution is critical in conservation and management. The Fishing Cat (Prionailurus viverrinus), a smaller feline native to South and Southeast Asia, is globally vulnerable and adapted to wetland habitats, with a diet primarily consisting of fish. This makes Bhitarkanika, a mangrove ecosystem, an ideal habitat for the Fishing Cat. This study was conducted to estimate the species density, determine the factors affecting its distribution, and assess the effect of lunar illumination and tidal fluctuation on Fishing Cat activity. Despite known occurrences of Fishing Cats in this area, there has been no proper assessment of their population or other ecological studies. Camera traps were deployed in 109 grids, each covering 1km², across a total of 145 km², for 2878 trap nights. Camera trap locations are unbaited, with two cameras used to capture both flanks. Spatially explicit capture-recapture (SECR) was used to estimate the density, resulting in 0.6 ± 0.1 individuals per km². The abundance was also calculated, with an estimate of 99 ± 16 individuals. These density estimates from this study are close to recent high-density estimates for the species. The canopy cover, the width of the creek, canopy cover and the distance to the aquaculture farms significantly influenced the Fishing Cat habitat use, indicating the need for the conservation of natural mangrove habitats and regulation of aquafarms present near the forest. In contrast, the presence of Saltwater Crocodile showed a negative effect on the distribution of Fishing Cats. The Fishing Cats were more active during the brighter nights of the moon phase (μ= 266.783, r= 0.051, p< 0.01) due to better visual detection. The activity was influenced both by the tidal fluctuations in terms of food resources from waterbodies and it is further enhanced by the lunar illumination during the night. Pairwise non-parametric tests showed that the probability distributions of Fishing Cat activity under lunar illumination and tide fluctuation (D= 0.125, p-value = 0.9885 and D= 0.125, p-value= 0.9899) were similar, indicating minimal differences between each probability distribution. This study underscores the importance of protecting the mangrove habitat and controlling aquaculture expansion to ensure Fishing Cat survival in the Bhitarkanika National Park.