M Sc Dissertation(WII)

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Author: search.filters.author.Sathyakumar, S.Subject: search.filters.subject.Food selection

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    Exploring ecological separation between Himalayan blue sheep and Himalayan ibex during winter in Indian Trans-Himalaya
    (Wildlife Institute of India, Dehradun, 2024) Prakruthi, G.M.; Sathyakumar, S.; Lyngdoh, Salvador; Bhatnagar, Yashveer
    According to resource selection theory, two related species with similar ecological requirements compete for the same resources. They can only coexist if they are ecologically separated, either by habitat or food preference. This study explored the resource use and ecological separation of ibex (Capra sibirica himalayanus) and blue sheep (Pseudois nayaur) during the winter in the Spiti Valley, focusing on their segregation in space, habitat use patterns, diet, and activity pattern. The study was conducted in Kibber and Chicham areas (57 km2) of Kibber Wildlife Sanctuary, Himachal Pradesh, India. This study slightly deviates from the findings of a previous study by Namgail (2006), which reveals a high overlap in the habitat use between ibex and blue sheep in the Zanskar mountains. Systematic sampling using transects and trails, vantage points, opportunistic sampling, and camera traps was employed. Habitat and vegetation variables were recorded at random points and animal sightings to understand the patterns of habitat use and food selection. Spatial and temporal overlaps were analysed and micro-histological analysis of faecal samples compared the proportions of monocots and dicots in their diets. The study investigated how ungulates utilize habitats and their dietary habits with the availability of resources in their environment. Results showed substantial overlap in activity patterns, with the Jaccard similarity index indicating less spatial overlap between the species. The generalized linear model and Non-metric dimensional analysis indicated segregation based on their habitat preferences. However, there were no significant differences in their diets, the two species differed in the use of habitat at finer scales. Ibex preferred interspersed rocky slopes and slabs because of high rocky areas (escape terrain) and sparse vegetation, trading food for security. Blue sheep preferred less rocky areas with high vegetation cover like smooth slopes. Ibex preferred areas with more escape routes available than blue sheep. Thus, I conclude that Blue sheep, being more abundant than ibex, occupy distinct regions within the study area, and have a competitive advantage. While ibex are present in smaller numbers and confined to a specific region. Understanding their ecological requirements, especially in harsh winters, is crucial for targeted conservation efforts to ensure the sustainability of these species in a rapidly changing environment. Future research should focus on climate change impacts on habitat use and resource availability
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    Food selection and ranging in hoolock gibbon (Hylobates hoolock Harlan 1834) in Borajan reserved forest, Assam
    (Wildlife Institute of India, Dehradun, 1997) Kakati, Kashmira; Sathyakumar, S.
    This study on food selection and ranging in the hoolock gibbon (Hylobates hoolock ,Harlan 1834) was carried out between December 1996 and April 1997 in Borajan Reserve Forest, a disturbed and fragmented patch of remnant tropical evergreen forest in Upper Assam, India. The hoolock gibbon is a primarily frugivorous species, confined to closed-canopy evergreen forests of North-east India, Bangladesh and Burma. This type is highly endangered in its entire range. Threats to the continued existence of the hoolock are from large-scale destruction of its habitat and hunting. Two troops of gibbons were followed intensively for four months and behavioural data were collected by continuous focal animal observations. Data were also collected ad libitum on a third troop. Data on the structural components of the vegetation and on the availability of food resources in the Intensive study area were collected systematically. The results of the study show that food availability influenced the diet, movement patterns, home-range sizes and behaviour of hoolock gibbons. Gibbons were selective in their diet using only forty-three plant species out of the more than two-hundred species present. Figs constituted important keystone resources for the gibbons. In months of low fruit availability, the gibbons had a predominantly folivorous diet. Home ranges were small (10.4 ha and 5.4 ha) and habitat degradation represents the greatest threat to the gibbons