M Sc Dissertation(WII)
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Item RISK ASSESSMENT OF POTENTIALLY TOXIC ELEMENTS IN THE HABITAT, AND DIET OF SMOOTH-COATED OTTER (Lutrogale perspicillata) IN TUNGABHADRA OTTER CONSERVATION RESERVE (TOCR), KARNATAKA(Wildlife Institute of India, Dehradun, 2024) Ahmed K., Niyaz; Johnson, J.A.; Hussain, S.A.; Sah, RuchikaSmooth-coated otter (Lutrogale perspicillata), is a vital indicator species for freshwater ecosystems, playing a crucial role in maintaining ecological balance. Despite their essential place in the food web, they are always neglected compared to other terrestrial carnivores. This study explores the distribution, diet, and, ecotoxicological exposures to smooth-coated otters in Tungabhadra Otter Conservation Reserve, Karnataka. The study area, encompassing a 36km stretch of the Tungabhadra River (TOCR), is a unique habitat facing significant anthropogenic pressures, including mining activities and pollution, which threaten the local biodiversity and otter populations. The distribution of smooth-coated otters in TOCR was assessed through intensive sign surveys, revealing a clumped distribution pattern. Otter signs, including spraints, pugmarks, and grooming sites were dominant signs found in the landscape. Dietary analysis was examined by analysing the spraints (scat), using two methods frequency of occurrence method, and the score bulk estimate method revealing a predominantly piscivorous diet. The diet consisted of about 14 species out of which 69.53% is constituted of non–native fish species (Oreochromis mossambicus, Labeo rohita, Cyprinus carpio, and Cirrhinus cirrhosus). Ecotoxicological assessments were performed on water, sediment, fish, and spraint samples to evaluate the presence of potentially toxic elements (PTEs). While PTE concentrations in water and sediment were generally below harmful thresholds, their presence poses a long-term risk through bioaccumulation. Risk assessment indicated significant potential health risks from metals like mercury and arsenic, which could impact otter healItem Resource Use and Distribution of Smooth-Coated Otter (Lutrogale perspicillata) in the Sub-Himalayan Foothill Rivers of Uttarakhand(Wildlife Institute of India, Dehradun, 2019) Basak, Sayanti; Hussain, S.A.; Gopi, G.V.Otters are the apex predators of the wetland ecosystems they inhabit. Being sensitive to both pollution and habitat destruction, the presence of otters in a wetland ecosystem, be it rivers, lakes, swamps, mangroves or estuaries, indicates the occurrence of a viable prey base, thus indicating an ecologically healthy condition of such ecosystems. Coupled with habitat, prey is one of the major factors that limit species populations. Many species, including otters, are often seen to cope up with disturbed surroundings only for the easy accessibility or abundance of prey in those areas. The aim of this study was to understand the ecology of Smooth- coated Otter (Lutrogale perspicillata) in terms of their habitat requirements, food habits, and distribution across the landscape. The study was conducted in select rivers of Rajaji National Park and Tiger Reserve, Lansdowne Forest Division, and Corbett National Park and Tiger Reserve. These protected areas fall in sub-Himalayan region, a region of high biodiversity value threatened by immense anthropogenic pressure. Habitat parameters were measured at every 250 m along a river bank and also in locations where there were otter evidences. The importance of different habitat parameters influencing otter occurrence were analysed using Generalised Linear Models (GLMs) and non-mapping technique using Bonferroni confidence interval approach. Smooth-coated Otter significantly preferred deep pools with moderate to sparse bank-side vegetation during the mid-winter and late-winter season. Moderate width water bodies are preferred over narrow water bodies. Muddy and sandy bank substrate types were preferred. Rocky stretches were largely avoided. Water body type i.e. pools and bank substrate type, i.e. rocky substrate, are the significantly influencing factors on otter distribution. Feeding habit of otters were studied by analysing 120 spraints collected throughout the study area. In this study, we also explored how the habitat suitability modelling could predict the percentage of area and a gradient of environmental conditions suitable for the occurrence of Smooth-coated Otter across the study area. MaxEnt modelling was used to predict habitat suitability of Smooth-coated Otter across the landscape. The most important variables affecting otter distribution were compound topographic index, Euclidean distance from the river, and slope position index. With increasing distance from water, and increasing slope, the suitability of an area to sustain otter populations decreased.Item Resource Selection and Conservation of Smooth coated otter Lutrogale perspicillata in and Around the Coringa Wildlife Sanctuary, Andhra Pradesh(Wildlife Institute of India, Dehradun, 2015) Prasad, Nadendla Leela; Sivakumar, K.; Johnson, J.A.; Hussain, S.A.Resource selection of Smooth-coated Otter Lutrogale perspicillata was studied in the Coringa Wildlife Sanctuary, where a two dimensional interface of fishermen-otter present: fishermen fishing in the habitat of otter and otters feeding in the aquaculture farms of fishermen. This is resulting in conflict between Otters and Humans in the region. In this context, this study was carried out to understand the extent of this conflict by studying the food habit of otters and ecological factors that could affect the otter distribution in this mangrove ecosystem. 2. The study was carried out from December 2014 to April 2015 in and around the Coringa Wildlife Sanctuary, which is located at the mouth of the Godavari River, in Andhra Pradesh. 3. Food habit of otters was studied by analysing their spraints that were collected from different parts of the Sanctuary. Habitat and distribution of otters were studied using belt transacts along creeks as otters mostly used banks of the creeks. Further, people perspectives towards otter and intensity of human-otter interface was studied using interview based questionnaire surveys. 4. It was found that the fishes cultured in the aquaculture farms were not present in the creeks of Coringa WLS. 6. The diet analysis of 81 spraints collected from December 2014 to March 2015 revealed that fish comprise of 99% of Smooth coated Otter diet. Of this major portion comprised of Mystus gulio, Oreochromis mossambicus and Liza tade. These species were also found in high abundance during the fish sampling from which relative abundance was calculated. This indicates that Otters in the sanctuary are opportunistic feeder rather than selective. 7. Mystus gulio (long whiskers catfish) found to be the major prey of otter in the Coringa . WLS, constituting 17.8% of weight of all food items found in the spraints and this fish was also eaten by many otters (found in 13.4% of spraints). M gulio was also the most common fishes of the Sanctuary. M gulio followed by Oreochromis mossambicus (Tilapia) constituting 14.6% of weight of all food items found in the spraints. 9. Although, all five major aquaculture species offish were found in the spraints of Otter but overall, the aqua farm fishes constituted only the 14.4% of weight of total foods items found in the spraints of otter. Of the total spraints collected, only 17.8% of spraints contained the aqua farm fishes and remaining 82.2 % otter spraints did not have. aqua farms fishes and these otters were seems to be eaten only the wild fishes. 10. The high abundance of invasive tilapia was found in the Ramannapalem creek, which is a less saline creeks adjoining with aqua farms and villages. This fish was the second most preferred diet of otters in the area. This fish breeds in the grasses that are at the banks of creeks. Breeding tilapia was a easier target for otters and therefore, otters were seen close to aqua farms. 11. The factors essential for Otter survival in were found to be more towards land and decrease with increasing distance from land. An ordinal regression model with sign intensity in three ranks revealed that the factors that are playa significant role in Otter distribution are distance from sea had a positive effect on Otter distribution (estimate = 0.403, Standard error =0.225 and P value= 0.073), Width of channel also had a positive effect to an extent (estimate =0.509, Standard error =0.273 and P value = 0.062). Depth of the creek had a negative effect (estimate= -0.624, Standard error = 0.322 and P value=O.053). 12. As the factors that are positively influencing Otter distribution are near villages Otters signs were also found highest in creeks near villages. Thus it was concluded that the presence of Otters mostly towards villages is probably due to presence of suitable habitat near villages rather than fish from aquaculture farms. 13. Fishermen's Traditional Ecological Knowledge of Otters in and around the Coringa Wildlife Sanctuary had also confirmed that otters largely feed in the wild but visit aqua farms occasionally for food or to play. Further, about 79% of people in the region felt that Otters visit their farms at night that confirms the nocturnal behaviour of Otters around human habitation, which is supported by previous studies 14. Further, most of fishermen (75%) believed that otters are high threat to aquaculture when compared to fishing cat and jackals. This is due to group hunting behaviours of otters, whereas fishing cats and jackals visit aquaculture ponds solitarily 15. Interestingly, nearly 11 % of fishermen felt that Otters have caused an income loss of 1-5% followed by 9% of respondents who claimed a loss of 10-30%. But, few farmers (2%) felt that Otters cause nearly 30-50% of loss, who were in the low income group and who can not offer even small loss in income. 16. Generalized Linear Model (GLM) with Poisson distribution revealed that both income and education of fishermen positively influenced their perspectives towards conservation importance of otters in the region. 17. Majority of fishermen (65%) believed that there was a decline in the sightings of otters and they have also believed that the population had been declined in the region. However, in contrast, about 13% of them felt that there was an increase in Otter population over years and most of these respondents who have also believed that high loss of income due to otters visits to their aqua farms. 18. Most of the aqua-farm owners admitted that they always scare and chase away otters when they visits their farms. Though only 11 % of them opted for killing does not mean that people have a positive attitude towards Otter. Boxplot analysis to understand the relationship between people's action towards visiting otters to their farms and their income and education, has revealed that the farm owners who had less income have tried to kill the visiting otters due to their poverty. 19. This study found that fishermen with poverty could not bear even the meagre loss caused by otters to them. Further, the study found that less educated people against the otters in the region. Therefore, additional livelihoods and awareness education to those poor fishermen need to be provided for the long term conservation of otters in the region. EGREE Foundation of Andhra Pradesh, a foundation established with support of GoI-UNDP-GEF Project to sustainably manage the Godavari estuarine has already initiated some programme in this regard but their programme should focus more on fishermen who are with low income 20. It is also proposed to have otter proof fencing for aquafarms especially those farms located along the Ramanapallam creeks. Developing eco- tourism in the sanctuary with the involvement of fishermen and small scale farm owners can also change their attitude towards otters.Item Relative sensitivity of mammalian carnivores to disturbance in sub-tropical forests of Arunachal pradesh(Wildlife Institute of India, Dehradun, 2005) Dada, Tamo; Hussain, S.A.Study the impacts of disturbance such as clearing of forests for habitation, presence of domestic livestock, forestry operation such as logging and extracting of non-timber forest products, trapping and hunting for sustenance as disturbance on carnivore populations. The study was conducted in the low land semi evergreen forests of Pakke Tiger Reserve, Arunachal Pradesh. For this study following objectives were identified • Prepare an inventory of carnivore species occurring in Pakke Tiger Reserve. • Study spatial and ecological distribution in terms of disturbances and environmental variables respectively. Four study sites, Khari, West bank, Dicho and Lanka were selected from within the Pakke Wildlife Sanctuary and adjoining Papum Reserve Forests, on the basis of various parameters which might have affected the habitat structure of the area. The influences of habitat variables on the occurrences of carnivore species were examined by using Classification tree analysis by using S-PLUS 4.5 software. The final output showed that, distances from village was the most important variable that determines the presence - absence of civets .Civets were absent in areas with more than 65 % shrub cover .Small cats occurred in areas with greater shrub cover and shrub height The occurrence of small cats decreased with the distances from village increased '. Small cat occurred low in areas with high canopy cover.Item Factors Affecting Habitat Selection and Feeding Habits of Smooth Coated Otter (Lutra perspicillata) in Periyar Tiger Reserve, Kerala(Wildlife Institute of India, Dehradun, 2001) Anoop, K.R.; Hussain, S.A.Otters are the top predators of the aquatic ecosystems. Despite their important place in the food web and wide distribution, the knowledge on their ecology is relatively scanty as compared to other carnivores. sediments. nutrients, energy and biota, dams interrupt most of the ecological processes of the river. This includes changes in the fish communities because of changes in water current and depth. The aim of this study was to look at how otters adapted themselves for living in a man modified aquatic system. The factors affecting habitat selection and feeding habits of smooth-coated otter was studied in Periyar Tiger Reserve, Kerala during November 2000 to April 2001. The importance of different habitat parameters influencing habitat selection was assessed using ordination technique. The food habit was examined by analyzing the spraints (scats) using both frequency of occurrence and score-bulk estimate methods. The habitat of the animal was visualized as a multidimensional space in which the animal selected a few combinations of parameters./Foraging sites with high densities of fish, areas that offer den sites. The signs that the animal leaves on the banks while using an area were identified as -holts, communal spraint sites, grooming sites and footprints. Presence of these signs were considered as sure indicators of intensive use of an area by the otters. Subsequently, 96 random plots of 250 x 10m (2.5 km2 area) were placed along the banks 'of the reservoir and each plot was characterized by means of 17 habitat variables. Of these variables, three viz. water depth, distance to vegetation cover (escape cover) and numbers of streams joining the lake were outside of the plot. Each of such plots was accordingly assigned to the category of either used or unused by the animal based on the presence or absence of evidences in the plots.The complex data collected from the plots was reduced to three uncorrelated axes using Principal Components Analysis sacrificing 300/0 of the variability of the system the plots had a position, which characterized them in terms of variety and variability. Then each of the plots was marked as either used or unused based on the evidences found in the plot. It was found in the newly created three-dimensional space, the used and unused areas were segregated in distinct regions. The coordinates of the used plots indicated that the otters selected less rocky areas of the shallower parts of lake, which are narrower and slanting. The number of streams joining these areas was more than other stretches of the lake and the vegetation on the banks was dense. The otters did not use the deeper and wider areas of the lake. Other unused areas were steep and rocky parts of the reservoir where no streams joined. The higher fish congregation in the areas of mouths of streams must be the reason why otters' used those areas more in comparison to other areas. The low water depth made the dives of otters in these areas more effective while foraging. The thick vegetation cover of the banks provided them shelter and narrower areas helped them in patch fishing i.e. reducing the chance of fish to escape by forming an arch around the shoals of fish. Mann - Whitney 'U' Test, confirmed this observed pattern.Then a logistic regression model was developed using animal presence I absence as the dependent variable and the habitat variables as covariates. The model selected only rockiness and number of streams from the complex set of variables to predict the probabilities of otter presence in each of the 94 plots chosen for characterizing the otter habitats. Out of the 70 plots, which showed positive signs of otters, 95.71 % were classified in the region of higher probability of occurrence. But out of the 24 plots, which showed no signs of otter occurrence, only 54.17% were correctly classified in the region of lower probability of occurrence. This shows that some of the areas, which showed no signs of otter presence, were potential areas but at the time of this study they were not using these areas for unknown reasons. This may also be due to the inherent problems of using spraints and tracks to assess the degree of use of an area by otters. Feeding habits of otter were studied by analyzing 94 spraints collected from around the Periyar lake. Prey remains were identified using standard references prepared with identified body parts for 12 fish species that were collected during the study period. Two methods were used to estimate the proportions of different prey items consumed viz. frequency of occurrence method and score-bulk estimate method. The former method takes into account the presence or absence of prey items with no consideration of its quantity whereas the later includes the quantity of each of the prey item consumed, by including proportion of each prey item in the spraint and total weight of the spraint. It was observed that in the frequency of occurrence method the major prey items were under estimated and minor items were over estimated, as it did not take into consideration, the proportion of each item individual The number of prey items in a spraint varied between 1 and 7 in a single scat, the average in lower water levels in the reservoir (December, January and February) being 3.21 (varied between 1 and 5) and during higher water levels (March and April) it was 2.73 (varied between 1 and 7). Fish was the major prey item (96.02%), followed by frogs - --(l.08%), crabs (l.07%), birds (1.07%) and insects (0.76%). During the study period. remains of six fish species were found in the spraints.Among these, Tilapia (Oreochromis mossambicus) was the major prey of otter (51.54% of the total diet) followed by catfish (Heteropneustes tossilis), which formed 21.27 % of the diet, curmuca barb Gonoproktopetrus curmuca; 12.37%) and European carp (Cyprinus caprio; 9.16%). A linear relationship was stablished between the total length of the fish and the length of the vertebrae. For this purpose a total of 43 fish belonging to different size classes were used and 215 measurements of vertebrae were taken. From the scat of otters, vertebrae were sorted out and lengths of the corresponding fish were found out. Otters seemed to be consistently taking more fish of size 8.0 cm to 15.0 cm (29% each), followed by 5.0 cm to 8.0 cm class (23.70/0) and 14.0 to 17.0 cm class (14.4%). Attempt to quantify fish availability in the lake to determine the preference failed because of the hindrance caused by submerged tree stumps that damaged the fishing nets. From this study it was concluded that the otters in Periyar lake have adapted to a man modified condition utilizing most common exotic fish species of the lake and selecting those stretches of the lake where the physical constraints of diving did not interfere much with their foraging success. They were also tolerant to a great deal of anthropogenic disturbances such as presence of motorboats and humans. This shows the remarkable adaptability of the species. Furthermore 60 % of the diet was found to be comprised of exotic fish. Thus the changes in the natural habitat both in terms of food and shelter has been successfully compensated by adopting alternate means for survival. As the entire catchment of Mullayar and Periyar are well inside the park boundaries, the pollution and anthropogenic disturbances are minimum in the lake. This may be the reason why Periyar is still supporting a healthy population of otters even though they are getting exterminated from many of its former distribution ranges. So the otter population Periyar Tiger Reserve should be considered as a precious possession of the park.