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Govindhan Veeraswami Gopi - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal partitioning between two sympatric crocodilians Gavialis gangeticus crocodylus palustris in katarniaghat wildlife sanctuary india
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Spatio‐temporal partitioning between two sympatric crocodilians (Gavialis gangeticus & Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Differential response to disturbance factors for the population of sympatric crocodilians (Gavialis gangeticus and Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation: Marine and Freshwater Ecosystems, 2017Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Katarniaghat Wildlife Sanctuary along the Indo‐Nepal border in India harbours a well‐known breeding gharial (Gavialis gangeticus) population in its global distribution range together with a substantial population of breeding muggers (Crocodylus palustris). However, no systematic information on size and structure is available for either of the species' populations in the protected area. This study was undertaken in winter and the ensuing summer of 2010–2011 to estimate the relative population density and structure of the two crocodilian species and to examine the effect of various disturbance factors, with the main focus on the effects of tourism and illegal fishing on the behavioural attributes of the two species. Five daytime surveys were conducted from December 2010 to April 2011. Relative density based on encounter rate (number per 20 km) was highest for gharial juveniles followed by gharial adults and gharial sub‐adults in all the five surveys. Muggers, on the other hand, showed the opposite trend, with the lowest encounter rate being for juveniles, followed by sub‐adults and adults. The encounter rate of both species declined with increase in the mean ambient temperature from December to April. The river habitat was divided into 2 km segments and disturbance factors were recorded at intervals of 100 m on both river banks. Wariness was taken as an indicator of response to disturbance caused by human beings and was measured from mechanized boats used for tourism and non‐mechanized boats used for illegal fishing. Segments with sandbars, in spite of moderate to high disturbance rate, were preferred for basking by both species. In conclusion, with suitable habitat for basking, gharials and muggers were observed to tolerate moderate levels of disturbance. Wariness resulting from disturbances from the non‐mechanized boats was higher than that from the mechanized boats. Gharials tend to avoid humans, possibly with age/size acquired experience and knowledge, whereas muggers become more tolerant to human presence with increased age/size. Despite many disturbance factors, the crocodilian population in Katarniaghat Wildlife Sanctuary is doing relatively well compared with populations in other habitats in India. With the involvement of local stakeholders and strict implementation of forest laws, the habitat can be further improved and a healthy gharial population can be ensured.
Shikha Choudhary - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal partitioning between two sympatric crocodilians Gavialis gangeticus crocodylus palustris in katarniaghat wildlife sanctuary india
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Spatio‐temporal partitioning between two sympatric crocodilians (Gavialis gangeticus & Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Differential response to disturbance factors for the population of sympatric crocodilians (Gavialis gangeticus and Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation: Marine and Freshwater Ecosystems, 2017Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Katarniaghat Wildlife Sanctuary along the Indo‐Nepal border in India harbours a well‐known breeding gharial (Gavialis gangeticus) population in its global distribution range together with a substantial population of breeding muggers (Crocodylus palustris). However, no systematic information on size and structure is available for either of the species' populations in the protected area. This study was undertaken in winter and the ensuing summer of 2010–2011 to estimate the relative population density and structure of the two crocodilian species and to examine the effect of various disturbance factors, with the main focus on the effects of tourism and illegal fishing on the behavioural attributes of the two species. Five daytime surveys were conducted from December 2010 to April 2011. Relative density based on encounter rate (number per 20 km) was highest for gharial juveniles followed by gharial adults and gharial sub‐adults in all the five surveys. Muggers, on the other hand, showed the opposite trend, with the lowest encounter rate being for juveniles, followed by sub‐adults and adults. The encounter rate of both species declined with increase in the mean ambient temperature from December to April. The river habitat was divided into 2 km segments and disturbance factors were recorded at intervals of 100 m on both river banks. Wariness was taken as an indicator of response to disturbance caused by human beings and was measured from mechanized boats used for tourism and non‐mechanized boats used for illegal fishing. Segments with sandbars, in spite of moderate to high disturbance rate, were preferred for basking by both species. In conclusion, with suitable habitat for basking, gharials and muggers were observed to tolerate moderate levels of disturbance. Wariness resulting from disturbances from the non‐mechanized boats was higher than that from the mechanized boats. Gharials tend to avoid humans, possibly with age/size acquired experience and knowledge, whereas muggers become more tolerant to human presence with increased age/size. Despite many disturbance factors, the crocodilian population in Katarniaghat Wildlife Sanctuary is doing relatively well compared with populations in other habitats in India. With the involvement of local stakeholders and strict implementation of forest laws, the habitat can be further improved and a healthy gharial population can be ensured.
Syed Ainul Hussain - One of the best experts on this subject based on the ideXlab platform.
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Microsatellite analysis reveals low genetic diversity in managed populations of the critically endangered gharial (Gavialis gangeticus) in India
Scientific Reports, 2021Co-Authors: Surya Prasad Sharma, Suyash Katdare, Niladri Dasgupta, Mirza Ghazanfarullah Ghazi, Samrat Mondol, Sandeep Kumar Gupta, Syed Ainul HussainAbstract:The gharial ( Gavialis gangeticus ) is a critically endangered crocodylian, endemic to the Indian subcontinent. The species has experienced severe population decline during the twentieth century owing to habitat loss, poaching, and mortalities in passive fishing. Its extant populations have largely recovered through translocation programmes initiated in 1975. Understanding the genetic status of these populations is crucial for evaluating the effectiveness of the ongoing conservation efforts. This study assessed the genetic diversity, population structure, and evidence of genetic bottlenecks of the two managed populations inhabiting the Chambal and Girwa Rivers, which hold nearly 80% of the global gharial populations. We used seven polymorphic nuclear microsatellite loci and a 520 bp partial fragment of the mitochondrial control region (CR). The overall mean allelic richness (Ar) was 2.80 ± 0.40, and the observed (Ho) and expected (He) heterozygosities were 0.40 ± 0.05 and 0.39 ± 0.05, respectively. We observed low levels of genetic differentiation between populations ( F _ST = 0.039, P
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microsatellite analysis reveals low genetic diversity in managed populations of the critically endangered gharial Gavialis gangeticus in india
Scientific Reports, 2021Co-Authors: Surya Prasad Sharma, Suyash Katdare, Niladri Dasgupta, Mirza Ghazanfarullah Ghazi, Samrat Mondol, Sandeep Kumar Gupta, Syed Ainul HussainAbstract:The gharial (Gavialis gangeticus) is a critically endangered crocodylian, endemic to the Indian subcontinent. The species has experienced severe population decline during the twentieth century owing to habitat loss, poaching, and mortalities in passive fishing. Its extant populations have largely recovered through translocation programmes initiated in 1975. Understanding the genetic status of these populations is crucial for evaluating the effectiveness of the ongoing conservation efforts. This study assessed the genetic diversity, population structure, and evidence of genetic bottlenecks of the two managed populations inhabiting the Chambal and Girwa Rivers, which hold nearly 80% of the global gharial populations. We used seven polymorphic nuclear microsatellite loci and a 520 bp partial fragment of the mitochondrial control region (CR). The overall mean allelic richness (Ar) was 2.80 ± 0.40, and the observed (Ho) and expected (He) heterozygosities were 0.40 ± 0.05 and 0.39 ± 0.05, respectively. We observed low levels of genetic differentiation between populations (FST = 0.039, P < 0.05; G'ST = 0.058, P < 0.05 Jost's D = 0.016, P < 0.05). The bottleneck analysis using the M ratio (Chambal = 0.31 ± 0.06; Girwa = 0.41 ± 0.12) suggested the presence of a genetic bottleneck in both populations. The mitochondrial CR also showed a low level of variation, with two haplotypes observed in the Girwa population. This study highlights the low level of genetic diversity in the two largest managed gharial populations in the wild. Hence, it is recommended to assess the genetic status of extant wild and captive gharial populations for planning future translocation programmes to ensure long-term survival in the wild.
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planning conservation for chambal river basin taking gharial Gavialis gangeticus and ganges river dolphin platanista gangetica as umbrella species
2013Co-Authors: Syed Ainul Hussain, Ruchi Badola, Rishikesh SharmaAbstract:This chapter describes the Chambal River basin and its conservation significance and discusses major issues affecting the conservation status. It also includes important aquatic fauna having Gharial (Gavialis gangeticus) as the flagship species followed by the Gangetic Dolphin Platanista gangetica, Indian Marsh Crocodile or Mugger (Crocodylus palustris) and Smooth-coated Otter (Lutrogale perspicillata). The Chambal River was identified as an important Gharial habitat in 1974 and was declared the “National Chambal Sanctuary” in 1978, followed by the “captive breeding programme” in 1979. Though the gharial population showed an increasing trend initially, since 2000, the population in the National Chambal Sanctuary has shown a dramatic decline. Between 1992 and 2000, 40% decline in the population was observed. The population of Ganges River Dolphin in the National Chambal Sanctuary was monitored during 1985–2007. The major issues affecting the integrity of the basin such as increasing human population, extraction of river water by the adjoining states of Madhya Pradesh, Rajasthan and Uttar Pradesh, discharge of industrial and domestic effluent into the river and control of soil erosion and ravine formation have been discussed. The prerequisites such as development and strengthening of the policy and legislation support for integrated river basin management, involvement of stakeholders and minimising the impacts of land use and water abstraction have been emphasised. As a conservation strategy, involvement of local communities through ecotourism, existing network of forest protection and village eco-development committees located in the basin have also been suggested.
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activity pattern behavioural activity and interspecific interaction of smooth coated otter lutrogale perspicillata in national chambal sanctuary india
2013Co-Authors: Syed Ainul HussainAbstract:The activity pattern, behavioural activity and interspecific interactions of smooth-coated otter (Lutrogale perspicillata) with crocodilians viz. gharial (Gavialis gangeticus) and mugger (Crocodylus palustris) was examined by monitoring four radio- implanted otters in the National Chambal Sanctuary, India. Based on the percentage of active telemetry recordings, the observed overall activity patterns of otters were in the form of a bimodal curve in which two periods of high activity were separated by a period of relative inactivity. In summer, the relative period of inactivity was greater than the winter and monsoons. Otters were more diurnal during winter than in summer or monsoon. Travelling and grooming were the most prevalent activities recorded during 422 sightings. Though the habitats and the diet of otters overlapped with gharial and mugger, their diurnal activity pattern was different and spatially they maintained a mutually agreeable strategy to avoid conflicts in sharing resources for basking and grooming.
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basking site and water depth selection by gharial Gavialis gangeticus gmelin 1789 crocodylia reptilia in national chambal sanctuary india and its implication for river conservation
Aquatic Conservation-marine and Freshwater Ecosystems, 2009Co-Authors: Syed Ainul HussainAbstract:1. The species diversity of inland waters is among the most threatened of all ecosystems and in many parts of the world it is in continuing and accelerating decline. Such decline could be restrained by acknowledging the scope of target species, so that all relevant stages in their life cycle are considered. 2. The gharial Gavialis gangeticus is a prominent riverine species of the Indus, Ganges, Brahmaputra and Mahanadi river systems that is becoming increasingly rare due to reduction in water flow and available nesting beaches, modification of river morphology and increased mortality in fishing nets. Despite these threats, scientific information on habitat selection by gharial is still inadequate, which hinders conservation measures. 3. This paper presents the population status, basking site selection and water depth preferences of different size-classes of gharial based on a study conducted in the National Chambal Sanctuary, India. 4. Between 1992 and 2007 a 40% decline in the gharial population was observed in the National Chambal Sanctuary. The decline was prominent in the recruitment class ( 180 to 270 cm) comprising both wild and reintroduced gharial. 5. Along the Chambal River, gharial preferred sandy parts of the river banks and sand bars for basking and showed less preference for rocky river banks and rocky outcrops. Clay river banks were least preferred. 6. Juvenile gharials 180 cm (including sub-adults and adults) preferred water depths >4 m. 7. Increasing demands for sand for development activities, and water abstraction for irrigation and energy generation coupled with mortality in fishing nets, are likely to affect gharial and other aquatic species, and steps need to be taken to maintain the minimum river flow necessary to sustain ecosystem processes. Copyright © 2009 John Wiley & Sons, Ltd.
Binod Chandra Choudhury - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal partitioning between two sympatric crocodilians Gavialis gangeticus crocodylus palustris in katarniaghat wildlife sanctuary india
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Spatio‐temporal partitioning between two sympatric crocodilians (Gavialis gangeticus & Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation-marine and Freshwater Ecosystems, 2018Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.
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Differential response to disturbance factors for the population of sympatric crocodilians (Gavialis gangeticus and Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India
Aquatic Conservation: Marine and Freshwater Ecosystems, 2017Co-Authors: Shikha Choudhary, Binod Chandra Choudhury, Govindhan Veeraswami GopiAbstract:Katarniaghat Wildlife Sanctuary along the Indo‐Nepal border in India harbours a well‐known breeding gharial (Gavialis gangeticus) population in its global distribution range together with a substantial population of breeding muggers (Crocodylus palustris). However, no systematic information on size and structure is available for either of the species' populations in the protected area. This study was undertaken in winter and the ensuing summer of 2010–2011 to estimate the relative population density and structure of the two crocodilian species and to examine the effect of various disturbance factors, with the main focus on the effects of tourism and illegal fishing on the behavioural attributes of the two species. Five daytime surveys were conducted from December 2010 to April 2011. Relative density based on encounter rate (number per 20 km) was highest for gharial juveniles followed by gharial adults and gharial sub‐adults in all the five surveys. Muggers, on the other hand, showed the opposite trend, with the lowest encounter rate being for juveniles, followed by sub‐adults and adults. The encounter rate of both species declined with increase in the mean ambient temperature from December to April. The river habitat was divided into 2 km segments and disturbance factors were recorded at intervals of 100 m on both river banks. Wariness was taken as an indicator of response to disturbance caused by human beings and was measured from mechanized boats used for tourism and non‐mechanized boats used for illegal fishing. Segments with sandbars, in spite of moderate to high disturbance rate, were preferred for basking by both species. In conclusion, with suitable habitat for basking, gharials and muggers were observed to tolerate moderate levels of disturbance. Wariness resulting from disturbances from the non‐mechanized boats was higher than that from the mechanized boats. Gharials tend to avoid humans, possibly with age/size acquired experience and knowledge, whereas muggers become more tolerant to human presence with increased age/size. Despite many disturbance factors, the crocodilian population in Katarniaghat Wildlife Sanctuary is doing relatively well compared with populations in other habitats in India. With the involvement of local stakeholders and strict implementation of forest laws, the habitat can be further improved and a healthy gharial population can be ensured.
Suraj Karki - One of the best experts on this subject based on the ideXlab platform.
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Counting crocodiles from the sky: monitoring the critically endangered gharial (Gavialis gangeticus) population with an unmanned aerial vehicle (UAV)
Journal of Unmanned Vehicle Systems, 2018Co-Authors: Gokarna Jung Thapa, Kanchan Thapa, Shant Raj Jnawali, Laxman Prasad Poudyal, Serge A. Wich, Ramesh Kumar Thapa, Suraj KarkiAbstract:Technology is rapidly changing the methods used in the field of wildlife monitoring. Unmanned aerial vehicles (UAV) are an example of a new technology that allows biologists to take to the air to m...
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counting crocodiles from the sky monitoring the critically endangered gharial Gavialis gangeticus population with an unmanned aerial vehicle uav
Journal of Unmanned Vehicle Systems, 2018Co-Authors: Gokarna Jung Thapa, Kanchan Thapa, Ramesh Thapa, Shant Raj Jnawali, Laxman Prasad Poudyal, Serge A. Wich, Suraj KarkiAbstract:Technology is rapidly changing the methods in the field of wildlife monitoring. Unmanned aerial vehicle (UAV) is an example of a new technology that allows biologists to take to the air to monitor wildlife. Fixed Wing UAV was used to monitor critically endangered gharial population along 46 km of the Babai River in Bardia National Park. The UAV was flown at an altitude of 80 m along 12 pre-designed missions with a search effort of 2.72 hours of flight time acquired a total of 11,799 images covering an effective surface area of 8.2 km2 of river bank habitat. The images taken from the UAV could differentiate between gharial and muggers. A total count of 33 gharials and 31 muggers with observed density (per km2) of 4.64 and 4.0 for gharial and mugger respectively. Comparison of count data between one-time UAV and multiple conventional visual encounter rate surveys data showed no significant difference in the mean. Basking season and turbidity were important factors for monitoring crocodiles along the river b...
