Theses and Dissertations
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Item 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 streamItem 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, SamuelCultural 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.Item Population genetic structure and differentiation of monitor lizard (Varanus bengalensis) for conservation and illegal trade monitoring(Wildlife Institute of India, Dehradun, 2024) Bala, Kumudini; Das, AbhijitThe population of Varanus continuously decline through their distribution range due to over hunting and destruction of their habitat through anthropogenic activity. Reduction in population size will cause low genetic diversity, which leads to inbreeding rendering the population unfit to survive and pushing it to the brink of extinction. Objectives are 1. To establish the genetic signatures of Varanus bengalensis from Terai Arc Landscape and augmenting the genetic database of the species from the opportunistically collected samples from other Indian states. 2. To inventories the Varanus biological samples at Wildlife Institute of India for determining their species, phylogenetic status and genetic variation. 3. To determine the population genetic structure of V. bengalensis from examined samplesItem Thermal Ecology of Spiny-tailed lizard and its vulnerability to climate warming.(Wildlife Institute of India, Dehradun, 2021) Tatu, Avichal; Dutta, Sutirtha; Das, AbhijitLizards and other ectotherms survive within their thermal limits and have a well-defined range of body temperatures within which their performance is optimal. Hence, as climate warming accelerates, ectotherms like lizards become increasingly constrained. Saara hardwickii survives in areas where environmental temperatures are already extreme. Therefore, they may be at the risk of extinction due to rising temperatures. In the field, we collected data on field body temperatures and operative temperatures to evaluate and quantify the degree of thermoregulation observed in the lizard and to evaluate changes in activity pattern over months, In the laboratory, we quantified preferred temperature, thermal thresholds and locomotor of the lizard. Using a combination of field and laboratory data, we described how S. hardwickii uses burrows to thermoregulate and evaluated how climate warming will impact locomotor performance and hours of activity in the future. We found that burrows provide an exceptional buffer to the lizards as the temperatures deep inside (~1 m) do not exceed the preferred temperature of the lizard, even in the worst-case climate change scenario (RCP 8.5). Currently, the lizards are restricted to their burrows for six hours during their active period. According to our model, by 2100, the lizards might get restricted to their burrows for 7 hours in the best-case scenario, and for 9 hours in worst-case scenario. Our model suggested decrease in locomotor performance by 2.1%, 9.5% and 28.3% in the best- (RCP 2.6), intermediate- (RCP 4.5), and worst- (RCP 8.5) case scenarios by 2100. Hence, the synergistic effect of loss of activity hours and decline in locomotor performance might result in decreased fitness of S. hardwickii, potentially leading to its extirpation.Item Montane Lizard in a Mosaic Landscape: Effect of Tea Plantations on Anamalai Spiny Lizard (Sales anamallayana)(Wildlife Institute of India, Dehradun, 2021) Devrajan, Anjitha; Ramesh, C.; Das, AbhijitThe Anamalai Spiny Lizard (Salea anamallayana), an agamid lizard endemic to southern Western Ghats is reported to use shola and tea plantations of Kannan Devan hills of high ranges of Kerala. The Western Ghats has experienced extensive habitat destruction and modification since a very long time and the lizards are highly affected by habitat modification which in turn affect their fitness and survival. In this study we investigated the effect of habitat modification on morphology, population and habitat association in Salea anamallayana in the shola forests of Eravikulam National Park and surrounding tea plantations. The study was conducted from February 2021 to May 2021. Line transect method was used to study density and Visual encounter surveys for collecting data for basking habitat use and morphology. Surveys were conducted from 9 am to 2 pm since the lizard was more active during the time period. Shola and plantation are structurally very different. Shola was divided into shola close to plantations and shola away from plantation. Plantation was classified according to the proximity to shola and presence of shade trees. The density was found to be more in shola (27.59±6.79/ha) compared to plantation (8.63 ±2.21/ha). In plantations, the density was influenced by proximity to shola and presence of shade trees. Density is more in plantations in close proximity to shola (20.91±4.51/ha) compared to plantations away from shola (2.85±1.37/ha) and the lizard was present only where the shade trees were planted. The sex ratio was biased towards male in plantations (100:14) and it improves in shola close to plantations (100:33) and further improves in shola away from plantations (100:50). The body condition of male lizards was poor in plantations compared to shola away from plantations (t = 2.57, df = 14.17, p-value = 0.021). The males do not differ in other morphological variables across the habitats. Body condition of males is better than females (t = -2.19, df = 23.80, p-value = 0.037). The basking habitat use is in proportion to habitat availability. The microhabitat use varies across shola and plantation. Average perch height and perch diameter is more in plantation and average canopy cover is more in shola. More diverse perch surface is available and used in shola compared to plantation. The average body temperature is high in plantation compared to shola and the body temperature is directly proportional to atmospheric temperature and substrate temperature. There is no significant difference in Flight Initiation Distance (FID) between shola and plantation. FID is inversely correlated to substrate temperature.Item A Countryside carnivore: aspect of leopard ecology at Jawai, Rajasthan(Wildlife Institute of India, Dehradun, 2017) Sharma, Ravi Kumar; Qureshi, Qamar; Das, Abhijit1.Increasing human population and habitat fragmentation has impacted the large carnivore population across India. Leopard among pantherine is more tolerant to human disturbance and co-occur with humans in the wide variety of habitats. 2. Study was undertaken to understand status of leopard and factors responsible for its survival in human-dominated landscape. 3. Study was conducted in Jawai Dam Community Conservation Reserve from December 2016 to April 2017 in a semi-arid region of Pali, Rajasthan, India We examined villager's perception towards leopard by taking out the percentage of each response of respondents. Tolerance and religious view toward leopards was found significantly similar with each other, villagers has higher economic losses (livestock loss by leopards) than benefits (tourism activities) generated by hotel lobby. Villagers were examined to have minimal loss of human life and injuries by leopards, so it's easy to say about existence than co-existence or co-occurrence of both leopard and human in Proposed lawai Leopard Community Conservation Reserve.Item 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, AshaAmphibians 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.