Theses and Dissertations

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Author: search.filters.author.Das, AbhijitSubject: search.filters.subject.Amphibians

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    Tadpoles with a Trick : Overwintering Ecology of Tadpoles in a Himalayan Stream, Uttarakhand India
    (Wildlife Institute of India, Dehradun, 2021) Jithin, V.; Das, Abhijit; Johnson, J.A.
    Overwintering is a unique phenomenon of delaying metamorphosis in amphibian larvae at low temperature conditions prevailing at high elevation and latitude. This study is first of its kind in India to look at selected ecological aspects of overwintering tadpoles of Nanorana spp. in a Himalayan stream
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    Assessing the Impact of Traditional Practice of Frog Consumption Amphibian Population from Mizoram India Culture -Nat
    (Wildlife Institute of India, Dehradun, 2021) Malsawmdawngliana; Das, Abhijit; Kawlni, Lallianpuii; Lalronunga, Samuel
    Cultural practices have shaped the natural resources around the area in all parts of the world. The traditional practices involving wildlife and their meat as food resources is widely practised by many tribes of the world. Such practice also involves amphibian exploitation as food, one of the critical reasons for the decline in the global amphibian population. Such practice is widespread in the Northeast part of India, including Mizoram. However, the population-level impact of such traditional practice is poorly known. The study was carried out in the buffer and core zone of Dampa Tiger Reserve (DTR) to assess the abundance and species richness. We surveyed four villages around DTR to see how the pattern of frog consumption by the local communities. The study tried to understand how the species diversity and abundance is affected by the off-take of frogs for food in the study area. Time constrained nocturnal Visual Encounter Survey method was used to see the species composition and abundances in the study area. Random sampling using questionnaires and interactions were used to see the frogs’ consumption pattern, medicinal use and preferred species for food of the local communities in the study area.
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    Toads on Roads : Effect of Linear Barrier on the Movement Ecology of Common Asian Toad (Duttaphrynus melanostictus)
    (Wildlife Institute of India, Dehradun, 2015) Sharma, Preeti; Das, Abhijit; Rajvanshi, Asha
    Amphibians in India are threatened by population decline and extinction. Conservation efforts are hindered by scanty knowledge on their movement pattern, habitat use and dispersal. Thus, I conducted first ever radio telemetry study on an Indian Amphibian species in Krishnan kovil, a village in Virudunagar district in Tamil Nadu state of India. The study was conducted over a stretch of 1.5 km on both sides of Kollam-Thirumangalam highway (NH 208). The objective was to know if there is any effect of road on the movement and population abundance of Duttaphrynus melanostictus, commonly known as common Asian toad. Reason for selecting a widespread perianthropic species is that such species can better indicate how gene flow is structured in an urban landscape. Total 9 adult individuals (5 ~ and 4 c)I) were tracked ranging between 12 to 41 days from February 1 - April 9, 2015. Findings of the study revealed that NH 208 has a significant effect (estimate 0.007589; standard error 0.003108) on linear displacement of toads that increases away from the road. However in case of village roads the linear displacements were higher near to the roads (estimate -0.01569; standard error 0.002977). This indicates that NH may be affecting the movement of amphibians as a potential physical barrier. However, village roads still seem to be permeable by the toads as they are using it for movement. Orientation data shows no significant orientation (Chi square value 1.19, P value 0.55) of movement of the toads. However, field observations show that movement of toads with NH was always along or away but never across it. Home range estimates show that animal # 6 (NHR6M) used largest home range of 4262.92 sq. meters and showed maximum linear displacement in one night up to 333m. Another aspect of the study was to determine effect of NH on population abundance of common Asian toad. I conducted mark recapture studies in one hectare plot at three sites. The abundance estimates are 228.97 (S.E. 14.09) individuals per hector for site 1, 125.59 (S.E. 9.68) individuals per hector for site 2, 365.94 (S.E. 46.85) individuals per hector for site 3. Abundance estimates at the 3 sites show an increasing trend with the increasing perpendicular distance from the NH. This indicates that the road may have an effect on the population of Duttaphrunus melanostictus. The study is limited to only one non breeding season (3 months), thus, is biased towards movement in less activity period. The study provides hitherto unknown information on toad movement with respect to linear barrier. Such studies are useful in developing realistic, predictive models useful for mitigation and restoration of dispersal corridors in a rapidly changing urban landscape. Results of this first ever amphibian radio telemetry study from India add to a new dimension in Indian amphibian research- beyond taxonomy.