M Sc Dissertation(WII)

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Author: search.filters.author.Pandav, BivashSubject: search.filters.subject.Distribution

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    Spatial Dynamics and Drivers of Nearshore Aggregations in Olive ridley Sea Turtles along the Gahirmatha Coast by
    (Wildlife Institute of India, Dehradun, 2024) Sarkar, Arnab Dey; Prabakaran, Nehru; Kumar, R.S.; Pandav, Bivash
    Olive ridley sea turtles (Lepidochelys olivacea) exhibit a well-documented phenomenon known as nearshore aggregation during their breeding season. These aggregations, comprising large numbers of turtles in shallow coastal waters, are a common feature observed along most of the mass nesting beaches. The ecological benefits of such aggregations are multifaceted, potentially including enhanced predator avoidance and increased opportunities for mate encounter. The importance of studying these nearshore aggregations stems from their vulnerability during this period. Olive ridley turtles within these aggregations are susceptible to various threats, including bycatch mortality from fishing gear. Understanding the spatial and temporal dynamics of these aggregations is crucial for developing effective conservation strategies. The Gahirmatha nesting site presents a unique case due to the influence of the Brahmani-Baitarani River system. The substantial freshwater inflow and sediment discharge from this river system have resulted in a vast area of shallow seabed compared to other nesting grounds. This distinct ecological setting necessitates a dedicated investigation into the dynamics and influencing factors of nearshore aggregations specific to Gahirmatha. The study examined the distribution and density of olive ridley sea turtles near Gahirmatha, India, a critical nesting site, with a particular focus on how environmental factors influence the location of these nearshore aggregations. Surveys were conducted throughout the breeding season, recording turtle sightings and environmental data. The findings reveal that olive ridley turtles are not distributed randomly in the nearshore waters. Instead, they form concentrated aggregations in shallow depths (less than 5 km offshore and 5-15 meters deep) before nesting. The location and density of these aggregations were not static but shifted throughout the breeding season. During the pre-nesting season, turtles were more dispersed across a wider area. As the season progressed and nesting approached, the aggregation grew denser and shifted closer to the nesting beach. The study also identified distance from the coastline and the nesting beach as the key factors influencing the distribution of these nearshore aggregations. Additionally, the unique shallow seabed near Gahirmatha, created by the discharge from the Brahmani-Baitarani River, might influence the preferred depth range of turtles compared to other nesting sites. Understanding these dynamic aggregation patterns is crucial for effective conservation efforts. Protecting these areas is essential for the well-being of this globally significant olive ridley population. However, it's important to acknowledge that the exact locations of these aggregations can vary between years. This year's lower nesting numbers suggest fewer turtles arrived in the nearshore waters, potentially impacting the size and distribution of the observed aggregations. This study emphasizes the need for long-term studies to gain a more comprehensive understanding of these variations and the factors influencing them. The study suggests a targeted approach of focusing on areas with high turtle usage. By implementing stricter patrolling measures within these zones, the forest department can significantly reduce threats like bycatch mortality from fishing activities. This targeted approach would be more effective in safeguarding the turtles compared to focusing on reducing illegal fishing in the entire sanctuary, considering the limited resources available.
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    Proximate Determinants of Ungulate Distribution and Abundance in Pilibhit Forest Division, Utter Pradesh, India
    (Wildlife Institute of India, Dehradun, 2011) Bista, Ashish; Ramesh, K.; Pandav, Bivash
    This study was conducted in Pilibhit Forest Division, Uttar Pradesh from December 2010-April 2011 to quantify the current status of ungulates, as a measure of tiger conservation efforts. The study focused on understanding the distribution and population size of ungulates in PiIibhit, and assessed the contribution of these species in tiger's diet. The study also looked into species-habitat association, at the level of proportion of habitat availability and grassland over space. Sampling framework followed Stratified Random Design, with spatially balanced approach. Estimates of distribution and population density were obtained following Single Season Occupancy Model and Distance sampling method. A total of 41 grids (5.20 sq km each) were sampled following the above framework. These grids were sampled based on 41 line transects ranging from 1 to 3 km long, which accounted for 288 km sampling efforts, including 3-5 temporal replicates for each transects. This study was carried out in four ranges (Mahof, Mala, Barahi & Haripur) of Pilibhit Forest Division with spatial coverage of ca. 420 sq km. Occupancy pattern of ungulates were in the order of chital (100%), hogdeer (17%), wild pig (93%), nilgai (81 %), swamp deer (11 %) and sambar (3%). Global density estimate of ungulates for Pilibhit Forest Division was 40.5 animals/sq km. The most abundant ungulate was chital (22.4/sq km), followed by nilgai (12/sq km) and hog deer (7.2/sq km). It was found that there were higher densities in edge habitats and that there was a particular association for grassland, signifying the importance grassland patches in the ungulate densities in terai habitats. Scat analysis (n= 24) revealed that hogdeer and wildpig, though occur in low densities, appeared to be the preferred prey, while chital contributed in tigers diet substantially in proportion to availability in the area. With given prey availability, forests of Pilibhit has the potential to support tiger population of 8.1 animal 100 sq km. The study highlights the significance of managed forests in terms of supporting considerable population of ungulates relevant for tiger conservation efforts. The study also supports the previous claim that grasslands support higher abundance of ungulate prey, and that in the absence of large sized prey, tiger switches to medium sized prey. The available information generated for the first time in Pilibhit Forest Division at large spatial scale provides a useful baseline for managers.