M Sc Dissertation(WII)
Permanent URI for this collectionhttp://192.168.202.180:4000/handle/123456789/3
Browse
3 results
Search Results
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 Avian Responses to Varying Landscape Parameters in Mangrove Forests of Coastal Gujarat(Wildlife Institute of India, Dehradun, 2015) Kulkadia, Devanshi; Talukdar, G.; Gopi, G.V.; Sivakumar, K.Mangrove systems are the most productive ecosystems on the earth. The mangrove environment provides living space for dependent biota of more than two thousand species of flora and fauna of resident, semi-resident or migratory wildlife. The conversion of large contiguous tracts of the tropical mangrove forests to smaller patches embedded in a landscape matrix surrounded by human-altered habitats is one of the most serious concerns as it would affect their associated species such as birds, fishes, etc. In this context, this study was carried out aiming at discerning the responses shown by avifauna to varying landscape parameters like the mangrove patch characteristics, the level of disturbance and the structure of mangrove vegetation. Therefore, the abundance and diversity of the avifauna in mangrove forests at twenty selected sites on the coasts of Gujarat were investigated using point count surveys for a period of five months (December 2014-April2015). 2. A total of 98 points were laid across the twenty patches o(mangroves and surveyed twice during winter and summer seasons, respectively. Data were collected from the four replicates of each point during the entire study period. The total area surveyed during the study at these twenty mangrove patches was 47.97sq.km. These patches were ranging from various size classes with the smallest patch of the size of 0.125sq.km to the largest patch size was of 10.49 sq.km and were distributed throughout the coastline of 1650 km long. Habitat correlates such as structural and floristic characteristics of mangroves were quantified for each patch to establish their relationship with avifaunal abundances. 3. Despite recording only 7 species of mangroves in the twenty patches, a wide variety of birds totaling to 119 species were recorded from the mangroves during the two seasons, i.e. winter and summer during the study. 4. From the data collected by the variable-width point counts, the mean density of birds from the patches were calculated to be 6.485/ha in winter and 4.898/ha in summer. The diversity of birds varied across the seasons. A total of 104 species of birds were recorded during the summer season as compared to 117 species of birds in winter season. 5. Large contiguous patches of mangroves were found to be supporting fewer species of birds than the smaller patches. The avian species richness of the smaller fragments were largely governed by the adjoining environment settings (matrix) of the patch. Therefore, the study found that the diversity of the birds was not found to be getting influenced by the area of the patch as the species richness was found to be increasing with the number of the surrounding matrix. 6. It was found that the structural composition of mangroves especially the canopy cover was found influence the bird density and diversity greatly as with the increase in the canopy cover, the bird species diversity and density also increased in a patch. 7. The bird assemblages in the mangroves showed a significant response towards the disturbance. The disturbed patches contained an overlapping mixed composition of the forest birds and open country birds in an equal proportion, whereas the undisturbed patches showed less number of open country birds. 8. Based on the study, it is suggested that the larger sized mangroves patches are important for their ineffable ecological services, therefore, these patches should be protected and conserved. Similarly, the smaller and fragment of mangroves patches are also equally important as they hold a good number of avifauna! species and hence, we have to adopt some strategies to conserve all the remaining – large contiguous and small fragmented patches of the mangroves from further degradation.Item Occupancy Pattern and Food-Niche Partitioning Among Sympatric Kingfishers in Bhitarkanika Mangroves, Orissa(Wildlife Institute of India, Dehradun, 2011) Borah, Joli; Pandav, Bivash; Gopi, G.V.Eight species of kingfishers, Common, Collared, White-throated, Pied, Stork-billed, Black-capped, Brown-winged and Rudy, - coexist in the mangrove forests of Bhitarkanika along the east coast of India. Sympatric species with similar resource requirements need to have niche partitioning as a strategy to avoid competition in order to coexist together. To understand the mechanisms underlying such species coexistence, it is vital to know about the food requirements, foraging habitat preference, and how the resources are shared between these sympatric species. The present study attempted to understand the potential mechanisms that might play a role in food-niche differentiation and examined the occupancy patterns of four sympatric kingfishers i.e. Common, Collared, Black-capped and Brown-winged kingfisher in Bhitarkanika mangroves. I conducted field study from January to May, 2011 in Bhitarkanika mangroves. The creeks were catgorized as primary, secondary and tertiary creeks based on the branching pattern. A total of 16, one km trails were selected in the intensive study area. Each 1 km trail was further divided into 10, 100 m segments for Sub-sampling. During the survey only seven among the 10 segments of each 1 km trail were surveyed which were selected randomly with replacement. A total of 160 creek segments of 100 m length were surveyed for six times during the study period and relevant habitat variables were recorded. For foraging behaviour observation, point count method was used i.e., an individual bird was followed till it captured a prey and relevant foraging variables were recorded. A total of 53 independent prey captures were recorded for the four species of kingfishers. Focal animal sampling method was used and observations were made opportunistically for time budget observation. Detection histories were constructed for each segment for bird survey and all relevant covariates. The two model parameters i.e., the probability that a segment is occupied by the species ('I') and the detection probability (P) were estimated and analysed in the occupancy framework. For foraging behaviour and time budget analysis, different parametric and nonparametric tests were used. Occupancy analysis confined that Collared and Black-capped Kingfisher occur seasonally in Bhitarkanika mangroves; Collared being more abundant in summer and Black-capped in winter. For all the four sympatric species river/creek width had a negative association with detection probability. Habitat type also affected the detection probability of all the species except Collared Kingfisher. The detection probability of Common and Black-capped Kingfisher decreased with the increase in depth whereas it did not affect the detection probability of Collared and Brown-winged Kingfishers. Water current and turbidity were negatively associated with the occupancy of Common and Brown-winged Kingfisher. However for Collared and Black-capped Kingfisher, it differed with vegetation layer. Perch height and foraging distance differed significantly among the four species of kingfishers. All the prey characteristics i.e., prey type, prey size and foraging substrate differed significantly among the four species of kingfishers. This study reveals that each of the four species of kingfishers in Bhitarkanika mangroves occupy foraging niches corresponding to their respective body sizes. The occupancy pattern and foraging behaviour of the smallest species, i.e., Common Kingfisher and the largest species, i.e., Brown-winged Kingfisher is more similar. As, both mostly forage in water to catch fish, their occupancy is also determined by water current. They segregate in terms of prey size, which is reflected by the respective body sizes. On the other hand, the foraging behaviour of Collared and Blackcapped Kingfisher is similar in terms of prey characteristics.