M Sc Dissertation(WII)
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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 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.Item Effect of habitat characteristics on waterbird diversity along river ganga in Allahabad, Uttar Pradesh(Wildlife Institute of India, Dehradun, 2017) Kumar, Ankit; Gopi, G.V.; Hussain, S.A.Riverine floodplains are a mosaic of different habitat available in the riverine area. It is extensively used by an array of flora and fauna. It supports a huge biodiversity by providing habitat as a resource to various taxa. Many waterbird species are directly and indirectly dependent on the riverine floodplains and use riverine habitat at a certain stage in their life cycle. The area also supports a high diversity of wintering waterbirds. Migratory bird takes refuge in the area during the severe winter in their native habitat. Habitat-specific species use different types of habitat present in the riverine floodplain. The riverine system also has an intricate relationship with the humans. Since a long time, these habitats are subjected to overexploitation that affects the natural ecological processes and the functioning of river. Degradations of floodplains of the major rivers of the world by alteration of water flow, encroachment in river islands and collection river bed materials, discharge of urban and industrial effluents, are threatening the biodiversity of rivers and their associated wetlands. The effect due to different levels of the disturbance is unknown on the diversity and abundance of waterbirds. On these lines, I conducted my study focused on identifying what are the habitat characteristics which is affecting the abundance and diversity of waterbirds and what are the anthropogenic factors affecting its diversity and abundance. The study was carried out in Allahabad District of Uttar Pradesh. It is known for the confluence of two major rivers of India, river Ganga, and its tributary river YamunaItem Diversity and abundance of birds in disturbed and undisturbed wetlands of Manipur river basin(Wildlife Institute of India, Dehradun, 2017) Sharma, Sijagurumanyum Rohikanta; Hussain, S.A.; Nair, Manoj V.; Tuboi, ChongpiThe Northeast (NE) Indian region is one of the hotspot of Indo Malayan biodiversity that remains largely unexplored. For this study, two wetlands in the NE Indian region of Manipur, viz Keibul Lamjao National Park (KLNP) and Pumlen pat (PP) were selected as the study site. Diversity and abundance of bird species in the region were assessed because of their prominence in the landscape. Conservation measures are needed for both the sites In tenns of these threatened bird species. Site-specific management strategies need to be incorporated in the management plan for the management of the isolated local populations of Black-breasted Parrotbill and Yellow-breasted Bunting in the undisturbed site (KLNP). Whereas some legal conservation measure is needed for conserving threatened grassland birds in the disturbed site (PP). It is also mandatory to monitor the population of Yellow-breasted Bunting population discovered from both the sites.Item Effect of Habitat Structure on Odonate Species Richness in Streams of Kalakkand Mundanthurai Tiger Reserve in Tamil Nadu India(Wildlife Institute of India, Dehradun, 2013) Anilitty, A.S.; Uniyal, V.P.; Johnson, J.A.This study aimed at the responses of species richness of Odonates toward the habitat structure in Kalakkad Mundanthurai Tiger Reserve(KMTR) in Tamil Nadu, India. KMTR lies between latitudes 8° 25' to 8° 53' N and longitudes 77°10' to 77° 35' E with altitude ranging from 50 meters to 1868 meters. Intensive study areas were confined to three beats in Mundanthurai and Kalakkad ranges of KMTR namely Kodamadi, Kannikatti and Sengaltheri. We sampled vegetation and stream structural parameters along with altitude and time of sampling from three drainages, River Thamiraparni, River Servalar and River Kil Manimuthar. Only the second, third and fourth order streams were sampled. Thirty six belt transects were laid and each transect was walked trice. A total of thirty six species were found during the study period. Species richness was calculated using Software· Estimate S version 0.8 and used to do GLM(Generalized Linear Model) in Software R version 3.0.1. Altitude was found to be the most influencing factor on species richness. A second GLM was carried out for the altitude wise stratified data incorporating temporal replicates for each transect. Tree height and stream width were found to be the most influencing factors in this model with p values 0.00007 and 0.001 respectively.Item Estimating sea snake diversity using trawler bycatch along the coast of Goa(Wildlife Institute of India, Dehradun, 2003) Lobo, Aaron Savio; Vasudevan, K.; Pandav, BivashThe sea snake community off the coast of Goa was studied using trawler bycatch. To obtain a fair idea of species richness .other fishing crafts such as shore seines and sluice nets were visited at regular intervals to check for snakes that were opportunistically caught in them. Catch per unit effort was calculated to compute the sea, snake abundance. Food habits of sea snakes were studied using a gut content analysis, where in the fish families commonly fed on by sea snakes were recorded. An attempt was made to understand the causes of mortalities in sea snakes. This was done relating the magnitude which was the number of dead sea snakes and intensity which was the proportion of dead sea snakes with the duration of the trawl, weight of the catch and mean depth in meters. Sea snakes were measured for several parameters and length-weight relationships were computed. A total of six species were encountered of which four were caught through systematic sampling using trawlers while the remaining two. were obtained through opportunistic searches using shore seines and sluice nets. The total catch per unit effort calculated for the entire study was 1.28 x 10-5 sea snakes per net/hr and the catch per unit efforts calculated for the individual bases varied significantly. The sea snake diversity was seen to be the highest for Vasco followed by Malim, Chapora and Betul. A cluster analysis with complete linkage showing similarities across the four different fishing bases showed that Vasco is most similar with Malim and Betul with Chapora. The composition of sea snake species varied with depth The proportion of Lapemis curtus increased and Enhydrina schistosa decreased with an increase in depth. The proportion of male and female snakes per trawl were similar in all three depths for L.curtus. In E.schistosa, however males did not occur in depths greater than 15 m. In L.curtus most individuals contained food in the stomach. The species was found to feed on five fish families of which families Clupeidae and Cynoglossidae dominated~ The consumption of clupeids decreased with increase in the length of the snake. Consumption of prey families varied slightly with the time of the day and this was mainly with the change in the proportion of Cynoglossids consumed.The mortality of sea snakes was found to be strongly related with the number of individuals caught. The magnitude and intensity of mortality were found to increase with the duration of the trawl, weight of the catch and mean depth. Mortalities of sea snakes varied with species, L.curtus having a larger proportion of dead than live individuals and E.schistosa having a larger proportion of live as compared to dead individuals, thus showing that L.curtus is more susceptible to mortalities- due to trawling as 'compared to E.schistOS8. Betul recorded the highest mortalities and the mortality of sea snakes was found to be significantly influenced by the time of the day and season. Bruises were found to vary significantly in live and dead sea snakes and were higher in dead snakes. Morphometric studies in L.curtus and E.schistosa found that snout vent length bore a strong relationship with the weight and tail length. No sexual dimorphism in terms of size was recorded in both the species which was similar to previous studies in the case of L.curtus.Item Avian Communities in the Riparian Areas of Bori Wildlife Sanctuary, India(Wildlife Institute of India, Dehradun, 1993) Pai, Ashwini; Johnsingh, A.J.T.Riparian areas are important as special habitats and corridors for wildlife. However, in India, riparian areas have not been studied to any detail. Also, not much is known about the avifauna of riparian habitats. The vegetation near a riparian area tends to be dense and hence distinct owing to constant availability of water. Riparian areas come under heavy use, both by livestock as well as wild animals because of the presence of water and forage. The avifauna of riparian areas is rich due to its floral complexity and structure and resources like fish and insects. This study quantified bird species diversity, avian guilds and avian community structure found in four riparian areas ( a flood plain, a riparian scrub, a disturbed nulla and an undisturbed nulla) of Bori sanctuary in Central India. The riparian areas were compared with the adjoining deciduous forest for avifaunal differences. Vegetation was studies along the riparian areas and the deciduous forests, using circular plots. Tree and shrub densities, vertical stratification of foliage and species richness were quantified. Line transects were used to estimate bird ,species richness and abundance. Bird species richness was correlated to negative variables for the two seasons. In summer the BSR was highly correlated with CC and in winters with CC. Stepwise multiple regression was used to create a habitat model for BSR in summer and in winter. Community patterns show seasonal change and also respond to structural changes of habitat.