M Sc Dissertation(WII)
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Item Spatial Dynamics and Drivers of Nearshore Aggregations in Olive ridley Sea Turtles along the Gahirmatha Coast by(Wildlife Institute of India, Dehradun, 2024) Sarkar, Arnab Dey; Prabakaran, Nehru; Kumar, R.S.; Pandav, BivashOlive ridley sea turtles (Lepidochelys olivacea) exhibit a well-documented phenomenon known as nearshore aggregation during their breeding season. These aggregations, comprising large numbers of turtles in shallow coastal waters, are a common feature observed along most of the mass nesting beaches. The ecological benefits of such aggregations are multifaceted, potentially including enhanced predator avoidance and increased opportunities for mate encounter. The importance of studying these nearshore aggregations stems from their vulnerability during this period. Olive ridley turtles within these aggregations are susceptible to various threats, including bycatch mortality from fishing gear. Understanding the spatial and temporal dynamics of these aggregations is crucial for developing effective conservation strategies. The Gahirmatha nesting site presents a unique case due to the influence of the Brahmani-Baitarani River system. The substantial freshwater inflow and sediment discharge from this river system have resulted in a vast area of shallow seabed compared to other nesting grounds. This distinct ecological setting necessitates a dedicated investigation into the dynamics and influencing factors of nearshore aggregations specific to Gahirmatha. The study examined the distribution and density of olive ridley sea turtles near Gahirmatha, India, a critical nesting site, with a particular focus on how environmental factors influence the location of these nearshore aggregations. Surveys were conducted throughout the breeding season, recording turtle sightings and environmental data. The findings reveal that olive ridley turtles are not distributed randomly in the nearshore waters. Instead, they form concentrated aggregations in shallow depths (less than 5 km offshore and 5-15 meters deep) before nesting. The location and density of these aggregations were not static but shifted throughout the breeding season. During the pre-nesting season, turtles were more dispersed across a wider area. As the season progressed and nesting approached, the aggregation grew denser and shifted closer to the nesting beach. The study also identified distance from the coastline and the nesting beach as the key factors influencing the distribution of these nearshore aggregations. Additionally, the unique shallow seabed near Gahirmatha, created by the discharge from the Brahmani-Baitarani River, might influence the preferred depth range of turtles compared to other nesting sites. Understanding these dynamic aggregation patterns is crucial for effective conservation efforts. Protecting these areas is essential for the well-being of this globally significant olive ridley population. However, it's important to acknowledge that the exact locations of these aggregations can vary between years. This year's lower nesting numbers suggest fewer turtles arrived in the nearshore waters, potentially impacting the size and distribution of the observed aggregations. This study emphasizes the need for long-term studies to gain a more comprehensive understanding of these variations and the factors influencing them. The study suggests a targeted approach of focusing on areas with high turtle usage. By implementing stricter patrolling measures within these zones, the forest department can significantly reduce threats like bycatch mortality from fishing activities. This targeted approach would be more effective in safeguarding the turtles compared to focusing on reducing illegal fishing in the entire sanctuary, considering the limited resources available.Item A Forked Relationship : Understanding the Acoustic Communication Strategies in Sympatric Drongos(Wildlife Institute of India, Dehradun, 2019) Lahiri, Sutirtha; Qureshi, Qamar; Kolipakam, V.The competitive exclusion principle states that ecologically similar species cannot co-exist and will either go extinct or develop diverging traits, the concept of environment filtering regards the environment. Patterns of trait divergence vary depending on whether the species occur in sympatry or in allopatry. Sympatry is defined as the co-occurrence of more than one species in the same geographical area with overlapping ranges. If closely related species occur in sympatry, competition is likely to shape divergence in their ecological as well as in the sensory domain, example acoustic signals. Diverse animal taxa employ acoustic signals for a variety of functions including mate choice, species identification, resource defence and other ecological and social functions. The primary aim of an acoustic signal is to efficiently communicate information over relatively long distances. This information, however, is subjected to changes and distortions imposed by the physical structure of the habitat, as well as masking interference from co-occurring signals of other acoustically communicating species. Masking interference by background noise or the simultaneously vocalization of other species- especially ones closely related- incur several disadvantages to the vocalizing individual. Signals with similar features have a high potential of interference for the species vocalizing, as well as for the receiver interpreting it. These disadvantages- or costs- could be the failure to respond to appropriate signals and the unnecessary response to territorial or mating signals not meant for them. However, a number of animals communicate successfully even in noisy and crowded environments, and can locate mates with relatively high success rates. This suggests the presence of powerful strategies to deal with the transmission, detection and recognition of relevant signals. To avoid acoustic competition due to the effect of masking interference, animals partition the acoustic resource in the temporal, spatial and spectral domains. Closely related species tend to be physically and behaviourally more similar than distantly related species, and are likely to possess similar songs and singing behaviour. The relationship between phylogenetic relatedness and trait similarity is investigated by quantifying what is called the ‘phylogenetic signal’- the tendency of related species to resemble each other more than is expected by chance. As a result, acoustic interference is likely to occur more often among closely related species, and they may evolve divergent signals to compensate. Drongos (Dicruridae) are a group of highly vocal passerines known for their vocal plasticity. There is a great extent to which their vocal repertoire can range in terms of diversity and function. Apart from having a wide range of species-specific repertoire, drongos are also mimetic species known to mimic the calls of conspecifics as well as other animals present in their environment. This study, conducted in Dehing Patkai Wildlife Sanctuary, Assam, focused on the four species of sympatric drongos- the Hair-crested Drongo, Lesser Racket-tailed Drongo, Greater Racket-tailed Drongo and Bronzed Drongo- and how they partition their acoustic niche. The study also looks into the ecological adaptations to counteract the impact of masking interference by habitat and closely related congeners. Active acoustic recording was done to record the four species of drongos in the study area. Line transects were walked along trails to calculate the density of each drongo species. Passive acoustic recorders were used to study the vocal activity patterns in the drongos. The study found evidence of overlapping acoustic niche between the drongos. However, they were significantly different from each other in the individual acoustic parameters. The drongos also occupied separate height classes, barring the lesser racket-tailed and the greater racket-tailed drongo. However, the drongos did not separate in their vocal activity pattern, suggesting overlap in the diel pattern. The study thus gives insight into the acoustic space of a group of highly versatile bird as well as the strategies they adapt to avoid interfering each other and thus co-exist.Item 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 Patterns of foraging in Olive Ridley Sea Turtle (Lepidochelys olivacea) Population on the East Coast of India and Habitat Characteristics of the Arribada Nesting Ground at Rushikulya(Wildlife Institute of India, Dehradun, 2019) Mudliar, Mohit; Sivakumar, K.; Gopi, G.V.; Shankar, KarthikThis study was conducted and aimed to explore the patterns of spatial segregation of foraging olive ridley turtles which nest on two distinct nesting areas of the eastern coast of India; secondly, to examine the characteristics of mass nesting ground of Rushikulya; and lastly, to assess the status of microplastic presence in mass nesting ground. The study found that the moisture contents and sand particle size were homogenous across the beaches of Rushikulya. The sandbar had most extreme values for four of the five studied habitat characters which might be due to surrounding waters. Sea turtles those stranded during December to February at Chennai as well as Rushikulya seems to be from a similar type of foraging areas as their carbon isotope ratio were not differentItem Responses of Raninforest Lizard Communities to Tea Plantation Edges in the Anamalai Hills of Southern Western Ghats India(Wildlife Institute of India, Dehradun, 2013) Malgaonkar, Aditya, S.; Habib, Bilal; Vasudevan, KarthikeyanHuman-made edges are an omnipresent form of altered habitats across the entire Western Ghats landscape. Furthermore a diverse range of edge types exist differing in the structure and composition of their altered surrounding habitat. Only a few attempts have been made to study the influence of the structure of this adjoining habitat or the 'matrix' on edge effects. Understanding the influence of different matrix habitats on edges will lead to the better understanding of the abiotic and biotic influences of the matrix on forest edges. Vegetation structure and composition has been the subject of several studies pertaining to fragmentation as well as effects of edges and both primary as well as secondary responses to edge effects have been documented. It has also been noted that while the reduction in plant species richness may occur as a result of decreasing forest area, it is more likely that this could be the result of increasing perimeter to area ratio resulting from fragmentation and increased proportion of area exposed to edge effects. The abiotic as well as biotic changes which affect vegetation not only bring about structural changes such as those in canopy cover, vertical stratification, density etc, but also affect functional aspects of plant communities such as pollination, seed dispersal and germination. Faunal communities respond in various ways to changes in their habitat; these may include changes in abundance, species richness, structure and composition of communities as well as behaviour of individual species. With respect to edge effect these changes or may vary in their magnitude and the distance or depth to which they penetrate into the interior. Magnitude and depth of influence are two complementary but distinct aspects of edge effects. Magnitl1de of influence is the degree to which a response value (a biotic or abiotic variable used to measure edge effects) differs between the edge and the interior while depth of influence if the maximum distance to which edge effects percolate into a habitat. However. A large amount of research on this topic has been restricted to birds and mammals and the responses shown by them might not be representative of the responses of other lesser known taxa.Item Age Estimation of a Breeding Population of Olive Ridley Sea Turtle (Lepidochelys olivacea) Along the Odisha Coast, Eastern India: Using skeletochronology(Wildlife Institute of India, Dehradun, 2013) Baburam, Anupya D.; Pandav, Bivash; Kumar, R.S.A migratory population of olive ridley sea turtle (Lepidochelys olivacea) forms huge reproductive congregations in the coastal waters of Odisha every winter. This breeding population of olive ridley has been subjected to heavy fisheries related mortality for the past two and half decades. Although a number of studies have been carried out on olive ridleys congregating and nesting along the Odisha coast, the impact of such large scale mortality on the demography of this breeding population has been least understood. The effect of this continued mortality on the age class of olive ridleys nesting along Odisha coast is not known. In order to understand the age class of this breeding population I carried out this study from December 2012 till May 2013. I used skeletochronological analysis to estimate the age class of this breeding olive ridley sea turtle population. Although this technique has been applied for marine turtles mostly in North Pacific, Atlantic and Gulf of Mexico coast of United States of America, no studies of this kind have been carried out on sea turtles of Eastern Pacific as well as Indian Ocean region. This study provides the information needed to bridge this gap and establish baseline for future skeletochronological studies on the breeding population of olive ridley. Humeral samples from 85 dead turtles (29 males and 56 females) washed ashore the Odisha coast was collected for skeletochronological studies. Cross sections were taken from the mid-diaphysis, just distal to the deltopectoral crest and beneath the insertion scar on the humerus were taken using first a Dremel 4000 round saw, then a freezing stage microtome. These sections were processed according to standardized histological techniques; growth rings on the stained humeral cross sections were counted to estimate age of dead turtles. Two age estimation protocols were used; the correction factor protocol and the ranking protocol; which yielded age estimates of 19.9 - 51.8 and 24 – 49 years respectively; for a size class of 56 - 74 cm (SCL). No correlation between size class and age was obtained from this analysis. This relationship was not established because the samples collected were from an adult breeding population, whereas, in the previous studies, sample collection represented individuals that greatly varied in size (hatchlings to adult). This study suggests that adult breeding population size class has no correlation with age; however, age can be correlated with size class of a younger population. This breeding population is sustaining a wide age group even though mortality rates are high in this areaItem Seasonal Habitat use of and Resource Partitioning between Two Sympatric Crocodilian Populations (Gavialis gangeticus and Crocodylus palustris) in Katerniaghat Wildlife Sanctuary, I(Wildlife Institute of India, Dehradun, 2011) Choudhary, Shikha; Choudhury, B.C.; Gopi, G.V.Gharial (Gavialis gangeticus) and Mugger (Crocodylus palustris) are sympatric in their distribution range in some of the Northern River system of Indian sub-continent. Katerniaghat Wildlife sanctuary along Indo-Nepal border in Uttar Pradesh harbours the second largest breeding population of critically endangered Gharial, after National Chambal Sanctuary. Several studies have been carried out on the ecological aspects of Gharial and Mugger separately but very few studies exist on the sympatric populations and the mechanisms favouring the coexistence of the species. This study has tried to fill this gap by investigating how the resources are shared (Basking sites and Nesting sites) and what are the key requirements that lead to the selection of a particular basking and nesting site. Temporal separation across species and size classes and preference for nearest neighbor has been established. Relative abundance in terms of encounter rate across season, river segments and a gradient of disturbances were studied. Other aspects that have been looked into detail in this study are the impact of tourism and illegal fishing on the flight distance of Gharial and Mugger. Data were collected from December 2010 to May 2011, covering two seasons (late winter and early summer). Entire study was carried out using a non-mechanised boat. Habitat parameters for every sighted basking crocodile were recorded for habitat use and for determining the habitat availability variables at every 100 meters on both banks and on islands were recorded. Nests were located by following the spoor marks of crocodiles. Gharial and Mugger were divided into three size classes (SCI - 3m). Once in a month day survey was carried out to estimate the relative abundance and on every alternate Monday temperature and number of basking individual were recorded at every hour from 0600 to 1800 hrs from a watch tower. Flight distance of crocodiles was recorded from a non-mechanised boat and a mechanised boat by accompanying the tourists. Relative abundance as mean encounter rate (#/20km) was maximum for Gharial juveniles followed by Gharial adult. Mugger juvenile had lowest mean encounter rate (#/20km). Encounter rate was not uniform for the river and it varies across season also. Maximum sightings took place in river segments with sand bars irrespective of moderate to high disturbance. With increase in mean ambient temperature encounter rate declined. Basking sites were selected during summer by Gharial based on depth gradient, current land usage, island, distance to water, slope, platform height and soil moisture while selection of basking site by mugger was based on current land usage, distance to water and depth gradient. In winter, Gharial selected sites based on slope, platform height, soil moisture, current land usage, distance to water and place while Mugger looked for current land usage, distance to water, islands and banks. In winter, there was no temporal segregation between different size classes of Gharial and Mugger while in summer there was a temporal segregation between and within size classes 0f Gharial and Mugger. Choice of slope, height, soil moisture, places and substrata for basking sites were different for Gharial and Mugger. Gharial preferred very gentle slope while Mugger preferred a slight slope. Gharials do not prefer elevated basking platforms whereas Mugger was found basking on elevated platform. GhariaI preferred moist areas for basking and Mugger basked even on little dry substrate. Gharial was seen mostly on Islands and Muggers on banks. Among basking substrate Gharial preferred sand & sand+silt, whereas Mugger was found on a variety of substrata. Mugger moved to side streams (Nalla) in summer while Gharial kept on preferring island for basking. For nest sites there is a significant difference in the use of slope, height, distance to water, places and substrate by Gharial and Mugger. Flight distance for crocodiles was more when there was a disturbance from non-mechanised boat than from a mechanised boat. Mechanised boat is mainly used for tourism purpose while non-mechanised boat for illegal fishing by local people. Between species Mugger was more tolerant to human presence than Gharial. Among hatchlings and adults of Gharial, hatchling showed a late response to disturbance while adults used to be the first one to slide in to water. Girwa river of Katerniaghat Wildlife Sanctuary is one of the very few rivers of India where Gharials re breeding in wild. Though the river stretch is about 20 - 21 km only a small stretch of 5-8 km harbours the maximum number of Gharial and Mugger. This small section is used for both basking and nesting and it is very crucial to protect this small stretch in order to save a critically endangered species from the brink of extinction.Item Factors Influencing Movement Pattern Habitat Use and Distribution of King Cobra (Ophiophagus hannah)- A Multiscale Approach(Wildlife Institute of India, Dehradun, 2011) Rao, Chetan S.; Talukdar, G.; Choudhury, B.C.The king cobra (Ophiophagus hannah) is the largest species of venomous snake in the world. It is a widely distributed species occurring in India and Southeast Asia. Most of the habitat use studies of ophidians are responses of ambient temperature. These results are often correlated with temperate areas where there is a significant shift in temperature annually. In tropical ecosystems, to understand ecology of a large bodied species like the king cobra would be interesting, knowing the fact that very little work has been done so far. The objective of my study was to procure relationship of ecographic variables on movement pattern, habitat use and distribution of king cobras at an individual and at a population level. This study was carried out in Agumbe, Karnataka in the Western Ghats region of India for 4 months during December 20 I 0 to April 2011 . Habitat utilization points were sampled throughout the study area, which basically was placed within the boundaries of a 2x2 sq.km grid enclosing all the presence locations collected during five years from the ongoing King Cobra Telemetry Project conducted by the Agumbe Rainforest Research Station and the University of Arizona in collaboration with the Karnataka state forest department. Retreat sites (n=262) were selected where the tagged (n=5) had been recorded and sampled for microhabitat variables. Nest sites (n=13) were also looked into, to explore site selection by females. A total of 30 ad libitum sightings of king cobras were recorded during the study. Prey density walk was carried out to derive a relative abundance based on encounter rate in the study area that came to be 1.24 animals/km. A total of 9 species of prey were encountered during prey density walks. The kernel estimates and minimum convex polygon for four radio tagged individuals was calculated for home ranges and area vs. availability was computed for habitat preference and use using Jacob's (1974) Index. The results of this study show a strong correlation of ambient temperature of range 20- 35°C (Beta coefficients 7.7eI0-l ± 0.0545) and relative humidity (70-90%) (Beta 15 coefficients 1.25 ± 1.14) with movement pattern and habitat site selection and also affect distribution patterns of this particular king cobra sub population. It is also found that king cobras do not particularly obligate themselves to a particular habitat type except for some degree of preference towards evergreen forest. The microhabitat however, influencing king cobra movement and habitat use are fallen logs on the forest floor (Beta coefficients 2.327e+00 ± 5.113e-Ol) and dead vegetation on the forest floor (Beta coefficients 2.042e-02 ± 6.796e-03) which have a stronger correlation with presence while ground burrows show a negative correlation. Leaf Litter Depth in the forest floor in sites with range of 4-7 inches deep (Beta coefficients 0.64269 ± 0.30998) influences nest site selection. Using secondary rescue data of five years and all the other presence records for king cobras in the wild, I ran a MaxEnt presence only model (auto model) using only environmental variables taken from BIOCLIM to test environmental parameters influencing distribution. The places of higher precipitation within the study area indicate a higher influence on occurrence and places of higher temperature and aridity regimes does not indicate occurrence of king cobras. The management recommendations for conserving such large bodied snakes would be a multidimensional approach. The local people within the study area do not kill king cobras, due to religious reasons. However, these attitudes are changing and so also some of the tolerant ideologies of the local people. King cobras have been found to occur more in a landscape matrix dominated by evergreen forests and decline in evergreen forest due to land use conversion could be the emerging possible threats to king cobra in the Western Ghats.Item Species Assemblage and Differential Basking Habitat Use of Freshwater Turtles in a Gradient of Mahanadi Riverine Ecosystem, Orissa(Wildlife Institute of India, Dehradun, 2009) Jani, Chandan; Choudhury, B.C.; Sivakumar, K.Of the seven species of turtles recorded in the Mahanadi River, this study recorded five species of freshwater turtles between Satkosia Gorge Wildlife Sanctuary and Khakadi (Near Cuttack city) during November 2008 to April 2009. Of these five species, four were softshell turtles (Nilssonia gangeticus, Nilssonia hurum, Chura indica, Lissemys punctata) and one was hardshell (Pangshura tentoria). Relative abundance in terms of mean number of individuals sighted per kilometre was estimated. The results showed that Pangshura tentoria was most abundant and was recorded over all the sampling zones, followed by Nilssonia gangetic vs Nilssonia hurum and Chitra indica. The latter three were not distributed as commonly as the former. Lissemys punctata was not included in the report as the species never sighted during the sampling secession. However, the species was found to get captured in incidental fish catch during the study period. The low abundance of Chitra indica and Nilssonia hurum might be due to degradation of their habitats. These two species are known to refer undisturbed and wider river stretches which are diminishing in the Mahanadi River. The habitats of the river stretch between Satkosia Gorge Wildlife Sanctuary and Kakhadi varied significantly and thus, explaining the variation in the species richness as well as abundance. The major habitat variables, which have highly influenced the turtle abundance were river flow, river width and river bank characteristics. Highest abundance of species was found in the non-riparian flow zones and river stretches with rocky and sandy banks, where the habitat heterogeneity was greater. These two sampling zones also experienced the least anthropogenic pressures. Choice in habitat use for basking in turtles was also observed. The choice of the habitat varied between species. Nilssonia gangetic and Nilssonia hurum preferred areas which had greater river bank width with shallow water near the bank. Chitra indica preferred areas where both river depth and river width were higher whereas bank slope, river slope, ground cover, alternative basking substrate and immediate water depth was lower. Pangshura tentoria preferred areas with greater river and bank slope along with greater availability of alternative basking substrate and greater immediate water depth. On the other hand they also preferred the habitat more close to the river with lower bank width and moderate river depth and moderate river width. Major threats to turtles in the Mahanadi river (sampling zones) are due to anthropogenic pressure and habitat degradation. Some of the threats were found to be consistent over the sampling zones. The study shows that Pangshura tentoria was highly tolerant to all prevailing threats in the Mahanadi river but, Nilssonia hurum and Chitra indica were adversely affected by these threats all along the river. This study found that there was a negative correlation between the turtle abundance and presence of threats such as sand mining, pump house, fishing and pollution. Sand mining adversely affected the basking habitat of most of the turtle species. Pump houses were largely avoided by the turtles which may be due to the vibrations or noise created at these stations. Unintentional by-catch of turtles during fishing was also observed especially in the braided flow zones and inundated static flow zones of the Mahanadi river. Sand mining and fishing are identified as the major threats to the turtles in the Mahanadi river, which should be monitored and regulated. Sand mining should not be allowed during the breeding season of the turtles especially in the area of Non riperian flow zone and braided flow zone. These two sampling zones were identified as the Important Turtles Areas (ITAs) in the Mahanadi River. Alternate livelihood options should be identified and implemented in order to reduce people's dependency on fishing in this region. Nature education and awareness programme clearly addressing the reason for declining of turtles and their habitat in the Mahanadi river needs to be launched.