M Sc Dissertation(WII)

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Author: search.filters.author.Hussain, S.A.Subject: search.filters.subject.Distribution

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    RISK ASSESSMENT OF POTENTIALLY TOXIC ELEMENTS IN THE HABITAT, AND DIET OF SMOOTH-COATED OTTER (Lutrogale perspicillata) IN TUNGABHADRA OTTER CONSERVATION RESERVE (TOCR), KARNATAKA
    (Wildlife Institute of India, Dehradun, 2024) Ahmed K., Niyaz; Johnson, J.A.; Hussain, S.A.; Sah, Ruchika
    Smooth-coated otter (Lutrogale perspicillata), is a vital indicator species for freshwater ecosystems, playing a crucial role in maintaining ecological balance. Despite their essential place in the food web, they are always neglected compared to other terrestrial carnivores. This study explores the distribution, diet, and, ecotoxicological exposures to smooth-coated otters in Tungabhadra Otter Conservation Reserve, Karnataka. The study area, encompassing a 36km stretch of the Tungabhadra River (TOCR), is a unique habitat facing significant anthropogenic pressures, including mining activities and pollution, which threaten the local biodiversity and otter populations. The distribution of smooth-coated otters in TOCR was assessed through intensive sign surveys, revealing a clumped distribution pattern. Otter signs, including spraints, pugmarks, and grooming sites were dominant signs found in the landscape. Dietary analysis was examined by analysing the spraints (scat), using two methods frequency of occurrence method, and the score bulk estimate method revealing a predominantly piscivorous diet. The diet consisted of about 14 species out of which 69.53% is constituted of non–native fish species (Oreochromis mossambicus, Labeo rohita, Cyprinus carpio, and Cirrhinus cirrhosus). Ecotoxicological assessments were performed on water, sediment, fish, and spraint samples to evaluate the presence of potentially toxic elements (PTEs). While PTE concentrations in water and sediment were generally below harmful thresholds, their presence poses a long-term risk through bioaccumulation. Risk assessment indicated significant potential health risks from metals like mercury and arsenic, which could impact otter heal
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    Resource Use and Distribution of Smooth-Coated Otter (Lutrogale perspicillata) in the Sub-Himalayan Foothill Rivers of Uttarakhand
    (Wildlife Institute of India, Dehradun, 2019) Basak, Sayanti; Hussain, S.A.; Gopi, G.V.
    Otters are the apex predators of the wetland ecosystems they inhabit. Being sensitive to both pollution and habitat destruction, the presence of otters in a wetland ecosystem, be it rivers, lakes, swamps, mangroves or estuaries, indicates the occurrence of a viable prey base, thus indicating an ecologically healthy condition of such ecosystems. Coupled with habitat, prey is one of the major factors that limit species populations. Many species, including otters, are often seen to cope up with disturbed surroundings only for the easy accessibility or abundance of prey in those areas. The aim of this study was to understand the ecology of Smooth- coated Otter (Lutrogale perspicillata) in terms of their habitat requirements, food habits, and distribution across the landscape. The study was conducted in select rivers of Rajaji National Park and Tiger Reserve, Lansdowne Forest Division, and Corbett National Park and Tiger Reserve. These protected areas fall in sub-Himalayan region, a region of high biodiversity value threatened by immense anthropogenic pressure. Habitat parameters were measured at every 250 m along a river bank and also in locations where there were otter evidences. The importance of different habitat parameters influencing otter occurrence were analysed using Generalised Linear Models (GLMs) and non-mapping technique using Bonferroni confidence interval approach. Smooth-coated Otter significantly preferred deep pools with moderate to sparse bank-side vegetation during the mid-winter and late-winter season. Moderate width water bodies are preferred over narrow water bodies. Muddy and sandy bank substrate types were preferred. Rocky stretches were largely avoided. Water body type i.e. pools and bank substrate type, i.e. rocky substrate, are the significantly influencing factors on otter distribution. Feeding habit of otters were studied by analysing 120 spraints collected throughout the study area. In this study, we also explored how the habitat suitability modelling could predict the percentage of area and a gradient of environmental conditions suitable for the occurrence of Smooth-coated Otter across the study area. MaxEnt modelling was used to predict habitat suitability of Smooth-coated Otter across the landscape. The most important variables affecting otter distribution were compound topographic index, Euclidean distance from the river, and slope position index. With increasing distance from water, and increasing slope, the suitability of an area to sustain otter populations decreased.