Browsing by Author "Das, Abhijit"

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A Countryside carnivore: aspect of leopard ecology at Jawai, Rajasthan
(Wildlife Institute of India, Dehradun, 2017) Sharma, Ravi Kumar; Qureshi, Qamar; Das, Abhijit
1.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.
A rapid herpetofaunal assessment in Lower Subansiri and Papum-Pare district, Arunchal Pradesh, India survey report 2020
(Wildlife Institute of India, Dehradun, 2020) Das, Abhijit; Boruah, Bitupan
Present study yielded 36 species of herpetofauna, of which amphibians represented by 19 species and reptiles by 17 species. All recorded amphibian species are anuran of which, Amolops marmoratus, A. monticola, Raorchestes sp., Zhangixalus smaragdinus, Theloderma asperum, Ingerana borealis and Fejervarya sp. were commonly observed in Potin. In Lichi species such as Euphlyctis cyanophlyctis, Duttaphrynus melanostictus, Fejervarya sp. were commonly encountered. Species belonging to the genus Liurana were only recorded from Talle WLS. Among the recorded reptiles, snake represented by 11 species and lizards represented by six species. Psammodynastes pulverulentus, Cyrtodactylus sp., Sphenomorphus sp. and Calotes jerdonii were frequently recorded in Potin. Study also recorded rare species of reptiles such as Boiga quincunciata and Pseudocalotes austeniana from Potin and Talle WLS respectively. During the study period, species richness was high in Potin as maximum survey was carried out in Potin than that of Lichi and Talle WLS. Few species recorded in the present study are identified upto generic level or referred to closely related species as systematic study of those species is needed. However, the number of herpetofaunal species in the study region will increase with further study as the present study was carried out for a short period. Besides recorded species of herpetofauna, the present study also documents species that were either conferred to closely related species (e.g., Polypedates cf. himalayanus, Asymblepharus cf. sikimmensis) or their identity remains to be ascertained (e.g., Nanorana sp., Raorchestes sp., Cyrtodactylus sp.). However, the present study was carried out for a short period and it indicates the number of herpetofaunal species in the study region will increase with further systematic study. The record
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.
Assessment of amphibians and reptilian diversity along Ganga river : progress report
(Wildlife Institute of India, Dehradun, 2021) Das, Abhijit; Hussain, S.A.; Johnson, J.A.; Boruah, Bitupan
In the present study an attempt has been made to survey the herpetofaunal diversity along Ganga River. The objectives of the study are to determine the species richness and diversity of herpetofauna along Ganga and Alaknanda river ii. To map the distribution of herpetofaunal species along Ganga and Alaknanda river iii. To study the reproductive biology of threatened amphibian species of the Ganga River Basin
Habitat Utilisation of Asian Water Monitor (Varanus salvator) in and Around Bhitarkanika National Park, Odisha
(Wildlife Institute of India, Dehradun, 2025) Rayen, W. Michael Isaac V.; Pandav, Bivash; Das, Abhijit
The water monitor lizard Varanus salvator is the largest of all lizards in India, and its distribution is restricted to certain pockets of the northeast, eastern coast and Andaman and Nicobar Islands. Despite being the largest lizard, only limited studies have been done on this species, especially on the movement pattern and home range. This study focuses on the space use pattern of Varanus salvator in the mangrove habitats of Bhitarkanika National Park, Odisha. In total, five individuals were radio-tagged with VHF transmitters in the form of a backpack. All the tagged individuals were located twice in a day, and the location(coordinates), activity and other habitat variables were recorded. The data collected were analysed for their movement pattern, activity range and overlap between individuals and the human-dominated landscape was estimated using KDE. Along with the space use environmental variables (Ambient temperature, Relative humidity, vegetation species, canopy openness, etc) were analysed individually with behaviour to the relation between them using Fisher’s test. The results from this study add more information about its activity range, movement pattern and behavioural aspects in the mangrove landscape of India, which can be useful in the rescue, rehabilitation and management of the species.
Impacts of roads on Indian Amphibians
(Wildlife Institute of India, Dehradun, 2017) Sharma, Preeti; Das, Abhijit
Macroecology of terrestrial herpetofauna in Andaman and Nicobar Archipelago
(Wildlife Institute of India, Dehradun, 2014) Harikrishnan, S.; Vasudevan, K.; Das, Abhijit; Choudhury, B.C.; Dutta, S.K.; Das, Indraneil
The islands arc system of Andaman & Nicobar Islands situated in the Bay of Bengal is a major contributor to the overall high biodiversity figures of India. These islands are part of two global biodiversity hotspots and contain an impressive array of endemic flora and fauna. The herpetofauna of these islands have been the subject of explorations since the 19th century when European naturalists started natural history collections in these islands. However, our understanding of the terrestrial herpetofauna of these islands has been restricted to anecdotal observations, field records and taxonomic studies.. We conducted a four year survey of terrestrial herpetofauna in Andaman & Nicobar Islands. During this period 24 islands were surveyed for terrestrial herpetofauna. For the sake of completion, data from prior surveys and museum records were also compiled. We recorded 65 species of terrestrial reptiles and 17 species of amphibians from across the Andaman & Nicobar Islands. We present a presence absence matrix for all species recorded from various islands. As expected, the largest islands had the highest number of species and smaller islands within an island groups tended to have communities that were subsets of the larger island community. Several new records and some new species were discovered during our surveys. We found that the terrestrial herpetofauna in Andaman & Nicobar Islands occur in relatively high densities in undisturbed habitats, reaching as high as 3630 individuals per hectare in Little Andaman Island. Patterns in body size distributions were mostly right skewed, but inter taxa differences were observed in this. The shape of body size distribution did not change between Andaman Islands and Nicobar Islands. Distribution of body sizes within communities of co-existing species of frogs and lizards revealed a highly structured distribution, but not in the case of snakes. Species cooccurrence patterns showed inter taxa and inter island group differences. Differences in biogeographic and colonization histories of both groups of islands are suspected to be the reasons behind the observed species co-occurrence patterns. Abundance and geographic distribution patterns were less clearly defined for both frogs and lizards. We suspect that introduced species such as chital and Indian bullfrog might have adverse impacts on native herpetofauna in the Andaman & Nicobar Islands. We attempt a classification of island herpetofauna according to their vulnerability to extinction. We also assess the current conservation status according to the IUCN criteria and legal protection status according to WPA, 1972, and show that majority of species occurring in the Andaman & Nicobar Islands have not yet been assessed properly. We conclude this report by providing a checklist of the herpetofauna, other than turtles and crocodiles, of Andaman & Nicobar Islands.
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, Abhijit
The 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.
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, Abhijit
The 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 samples
Reproductive behaviour of Raochestes shillongensis (pillai and Chanda 1973) from Meghalaya , Northeastern India
(Wildlife Institute of India, Dehradun, 2017) Boruah, Bitupan; Saikia, Uttam; Das, Abhijit
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
Thermal Ecology of Spiny-tailed lizard and its vulnerability to climate warming.
(Wildlife Institute of India, Dehradun, 2021) Tatu, Avichal; Dutta, Sutirtha; Das, Abhijit
Lizards 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.
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.
Tortoises and Freshwater Turtles of Kaziranga National Park, AssamDiversity, Distribution, Conservation Status.
(Wildlife Institute of India, Dehradun, 2009) Ahmed, M. Firoz; Das, Abhijit
X-mas Bush frog Raorchestes shillongensis (Pillai and Chanda, 1973) Conservation Project, Meghalaya India
(Wildlife Institute of India, Dehradun, 2017) Das, Abhijit; Boruah, Bitupan