Theses and Dissertations
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Item Feeding ecology and habitat needs of wolves (Canis lupus pallipes) in the Bhal area of Gujarat.(Wildlife Institute of India, Dehradun, 2002) Jethva, Bharat D.; Jhala, Y.V.Present study was conducted in the Bhal region of Gujarat between 1996-2000 to study the feeding ecology and habitat needs of wolves. Food habits of wolves in the Bhal were studied by analyzing 1246 wolf scats from 5 packs. Standardization of scat analysis technique suggested that minimum of20 hair should be scanned per scat to get complete representation of mammalian prey species in that scat. Minimum number of scats that need to be analyzed per pack were different for different wolf packs (ranging from 165 scats needed for Velavadar National Park (VNP) pack to 40 scats from Mithapur pack and 180 scats for the wolves of entire Bhal) because of different diet diversity. Mammalian prey species dominated in the diet of wolves and 80.5% scats were found with only one prey species. Comparative account on feeding ecology provided in the present study by scat analysis and monitoring of radio-collared wolves suggests that wolves depends primarily on wild prey species (blackbuck being major prey) and predation on domestic livestock results in minimal economic loss to the local people. It emphasizes the importance of protected areas for the conservation of wolves. Use of radio-telemetry in the present study provided critical information on territorial behavior of wolves, their population density, size of home range and their relation with prey abundance, habitat use and the size and characteristics of core areas.Item Interactions between forage, recruitment and activity patterns of Blackbuck (Antelope cervicapra)(Wildlife Institute of India, 2005) Priyadarshini, K.V.R.; Jhala, Y.V.In this study based on the seasonality of blackbuck calving in VNP and examined whether birth synchrony exists in this population. I assessed the seasonal patterns in forage vailability, quality, and body condition of blackbuck females, and examined if changes in forage availability, quality and body condition of females influenced calving seasonality. · Forage variables that were measured are, aboveground grass biomass, moisture, crude protein, ADF, lignins, and silica content in grasses. Some of the forage variables showed considerable seasonal changes, while some did not. Biomass was the highest in the cold and late wet seasons and lowest in the dry season. Crude protein content was the highest in wet season and the lowest in dry season. Blackbuck in VNP appear to have a cyclical calving pattern. The dry season calving peak was probably timed to the impending peak in forage quality, which would have benefited the calves when they weaned. The wet season calving peak occurred after a gap that corresponded to inter-calving interval in blackbuck. The females that calved in the wet season perhaps provided greater maternal nutritional investment into the young, which might have compensated for the lower quality forage that was available to the calves when they weaned. In this study based on the seasonality of blackbuck calving in VNP and examined whether birth synchrony exists in this population. I assessed the seasonal patterns in forage availability, quality, and body condition of blackbuck females, and examined if changes in forage availability, quality and body condition of females influenced calving seasonality.· Forage variables that were measured are, aboveground grass biomass, moisture, crude protein, ADF, lignins, and silica content in grasses. Some of the forage variables showed considerable seasonal changes, while some did not. Biomass was the highest in the cold and late wet seasons and lowest in the dry season. Crude protein content was the highest in wet season and the lowest in dry season. Blackbuck in VNP appear to have a cyclical calving pattern. The dry season calving peak was probably timed to the impending peak in forage quality, which would have benefited the calves when they weaned. The wet season calving peak occurred after a gap that corresponded to inter-calving interval in blackbuck. The females that calved in the wet season perhaps provided greater maternal nutritional investment into the young, which might have compensated for the lower quality forage that was available to the calves when they weaned.Item Resource utilization and parental investment in the Indian for (Vulpes bengalensis) in Kutch, Gujarat(Wildlife Institute of India, Dehradun, 2005) Home, Chandrima; Jhala, Y.V.I studied the resource utilization patterns in the Indian fox (Vulpes bengalensis) with respect to diet in Kutch, Gujarat. Resource use and availability by foxes were compared between two habitats and between two seasons. Resource availability was quantified through transects laid in both the habitats for the different prey items: mainly mammals, birds, reptiles, arthropods and fruits. Resource availability differed in both the habitats as well as across seasons (summer and winter). Density of fruiting shrubs (particularly Zizyphus) and gerbil burrows were significantly different between the two habitats. Gerbil population mean obtained from different colonies trapped during the study period showed a significant relationship with the total number of burrows in the colony (R2 =0.969). Scats collected from den sites were used to quantify resource use of the Indian fox. The minimum number of scats that can be used to estimate the annual food habits of the Indian fox in' a dry arid area like Kutch is about 110 scats. Frequency of occurrence of prey species also differed across habitat and seasons. The food habits of the Indian fox comprised of varied items, mainly arthropods like beetles, orthopterans, scorpions and termites. Among the other items, rodents, hares, spiny tailed lizards, birds and eggshells as well as fruits have been found. Arthropods were the most frequently occurring prey items (75% and above), among them particularly the termites. They are seen to be selected more than availability within the habitat. This was indicated by the three methods used to compare use versus availability (Ivlev's Index, Bonferroni's CI, and Compositional Analysis). However the Indian fox is seen to maximize energy requirements by selecting gerbils next in the preference after arthropods being selected more than availability during most cases within the habitat. Density of breeding units evaluated in the scrubland showed a density of 0.1 O/sq Ian. The density of breeding pairs obtained in this particular study was much higher as compared to the ones reported earlier for Kutch (0.04-0.06/sq Ian) due to good rainfall in the preceding two years thereby indicating a good prey base as compared to other years.Item Evaluating Tiger (Panthera tigris) Population Estimation Approches in a High Density Area in Kanha Tiger Reserve(Wildlife Institute of India, Dehradun, 2005) Sharma, Rishi Kumar; Jhala, Y.V.Reliable estimates of status and population trends are critical for the conservation of large terrestrial carnivores as they play an important role in evaluating effectiveness of conservation efforts and also provide benchmark data for future management decisions. Camera trapping technique have been widely used for population estimation of cryptic carnivores including tigers, but the issues regarding sampling design and effort required to effectively sample an area have been paid less attention. An attempt was made to deal with these issues in the present study. The use of intensive search effort for tiger density estimation was also evaluated. Over a 30- day survey period, 33 camera trap sites were sampled in Kanha meadows of the Kanha Tiger Reserve. A total sampling effort of 330 trap nights yielded 39 photocaptures of 12 individual tigers over 10 sampling occasions that effectively covered a 111-km2 area. The model M(o) fitted the capture history data well. The estimated capture probability/sample, p-hat = 0.22, resulted in an estimated population size and standard error (N(SE TV)) of 13 (1.19), and a density (D(SE Z))) of 11.71 (1.74)7100 km2. Camera spacing was found to considerably influence the population estimation. An increase in camera spacing from 1.5 to 2.5 km resulted in a loss of 35% (n=7) of photo captures which consequently decreased the precision of the estimates, though accuracy was not affected. A reduction in the trapping effort in terms of reduced trap nights resulted in lower level of precision though the accuracy of estimates was not affected. Increase in the camera spacing from 1 to 2 km with a decrease in the number of sampling occasions (six) resulted in the loss of 42% of photo captures (n=12) and loss of 25% of individual tigers (Mz+/=9) thus underestimating the true tiger population by 16% ((N(SE N)) being 10(1.84) The data also suggests that the photo-captures are not likely to generate abundance index for species other than tigers, since the cameras are placed to maximize tiger captures in space and time. My results suggest that a thorough reconnaissance survey is of utmost importance for camera trapping studies as it can help to maximize the capture probability of tigers and circumvent the sampling problems. The different statistical estimator’s viz. capture-recapture, jackknife and bootstrap did not show significant differences in the population estimation. Bootstrap estimator performed better than jackknife in terms of greater precision. The differences between the density estimates generated by “camera trapping” (D=l 1.71/100 km2, S.E.=1.74) and “intensive search effort” (0=12.74/100 km2, S.E.=2.27) for tigers were not significantly different. Our results suggest that “intensive search effort” for tigers if used within capture-recapture framework can be used to arrive at reliable population estimationItem Disturbance and Coral Community Structure in the Intertidal Coral Reefs of the Southern Gulf of Kutch(Wildlife Institute of India, Dehradun, 1995) Arthur, Rohan; Jhala, Y.V.I quantified the coral community structure using quadrat sampling in two intertidal coral reefs off the island of Narrara and Pirotan in the Southern Gulf of Kutch. These areas are subject to heavy disturbance from industries, and anthropogenic pressures on the reef are considerable. Species richness and indices of diversity indicate the reefs are of low diversity. Species diversity values indicate that Narrara has a lower species diversity (H'= 2.822, SE 0.139) than Pirotan (H'= 3.95, SE 0.126) (t-test d.f. = 236, P < 0.00 I). However, environmental data collected from both areas indicate that the levels of disturbance, measured as the mean percentages of dead coral, sediment load on live coral, algae cover and bleaching, was generally higher in Pirotan than in Nanara. Multivariate techniques of analysis were used to elucidate these trends. Community clustering using the statistical package TWINSPAN and direct ordination using Canonical Correspondence (statistical package CANOCO) were carried out. Axis I correlated well with the percentage of boulders in the reef and the density of algae, and Axis 11 correlated well with sediment load on the coral. Species showed clear patterns of distribution along these axes. I set up experiments to test the effect of crude oil and bittern, a salt manufacturing by-product, on two common reef Scleractinidia, Porites compressa and Favia favus. Significant effects were seen with both pollutants. Most of the replicates showed some level of recovery though this recovery did not result in any of the coral regaining total health. Indices of coral sensitivity and coral recovery was developed and this proved a valuable means of comparing the response of different species. Bittern and crude oil stressed the corals and resulted in sediment deposition. The immediate cause of mortality was caused by sediment deposits on the coral boulders. In highly turbid reefs, coral species might be affected more by high sedimentation levels than by other environmental stressorsItem Aspects of Foraging, Activity, Habitat Use and Demography of Rhinoceros (Rhinoceros unicornis Linn.) in Royal Chitwan National Park, Nepal(Wildlife Institute of India, Dehradun, 2003) Kandel, Ram Chandra; Jhala, Y.V.The study was conducted between November 2002 to June 2003 in the Royal Chitwan National Park, in Central Terai which arbors the largest population of the Great One-honed Rhinoceros (Rhinoceros unicornis Linn) in Nepal. I studied time Activity budget, Habitat use, preference, food habits and ranging pattern of free ranging rhinos by continuously monitoring them from elephant back for 130.5 hrs (10 sessions of 7-24 hr each)Item Home Range, Ranging Patterns and Abundance Estimation of Golden Jackals in the BHAL Region of Gujarat(Wildlife Institute of India, Dehradun, 2001) Aiyadurai, Ambika; Jhala, Y.V.Studied Golden Jackals (Canis aureus) in the Bhal area of Gujarat using radiotelemetry. Six jackals were trapped in Velavadar.National Park during November and December 2000 using rubber-padded leg-hald traps. The average home range size of jackals was estimated to be 14. 30 ± 4.06 sq. km. The core areas of jackal home ranges were highly correlated with vegetation cover. Habitats preferred for core areas were Prosopis juliflora and grasslands. Jackals ranged an average distance of 6.8 ± 0.91 km in a night. Most movements were out of the park to surrounding villages, which were rich in food resources for jackals. I evaluated two techniques to estimate jackal abundance namely the track plot method and simulated howling responses method in six areas differing in jackal abundances in the Bhal and Kutch regions. The latter technique gave a better resolution of abundance categories within the study sites.Item Evaluation of Pugmark Census Technique(Wildlife Institute of India, Dehradun, 2001) Sharma, Sandeep; Jhala, Y.V.Effective conservation strategies hinge on reliable population estimation technique. The potential of pugmark as a tool for population estimation of tigers was statistically examined. Eleven variables were selected and they were found effective in discrimination between individual tigers. These variables also discriminated between male & female in a population of 10 known tigers with 100% accuracy. This sex discrimination modal was found 97.4% accurate during validation over three new known tigers. The above said variables were also robust for pooling left and right pugmark. The soil depth of range 0.5 cm to 2 cm was found to be ideal for PI P preparation, since the 11 predictor variables were examined to be insensitive towards shape and size change of pugmark due to substrate condition. Classification of 17 individual tigers was achieved with 97% accuracy using stepwise discriminant function analysis. The statistical protocol developed in this study was found to be 100% accurate in predicting the correct number of tigers and correct classification of pugmarks, during validation in a blind set simulated 'census-exercise' from a known number of tigers (some of the track sets used for this analysis were not used for developing the DFA model). Variability in pugmark tracings due to tracer's effect was found to be significant. ANOVA (p-value 0.002 with df-1, df-53) results suggest a significant difference between variables measured from tracings and those from photos. However, DFA was unable to discriminate between tracings and photographs suggesting that either could be used in the model. Seventy five percent of the "experts" (n=8) were 100% correct in deciphering individual tigers in a blind test involving 15 tiger pugmarks from 7 individual tigers. The remaining 2 experts overestimated the tiger numbers by 1. The experts had an accuracy of 92% (sd = 7.8) in correct classification of tiger pugmarks. The other groups of respondents, ecologists (n=11) and lay persons (n=15) overestimated the tiger numbers and had an accuracy rate of 670/0 (sd = 24), and 640/0 (sd = 6) respectively in classifying pugmarks correctly. This study suggests that pugmarks can be used as a tool for population estimation of tigers, if subjected to analytical protocol developed here in within the constraints outlined.Item Effects of Grazing, Utilisation and Management on the Grasslands of Royal Bardia National Park, Nepal(Wildlife Institute of India, Dehradun, 1997) Karki, Jhamak Bahadur; Jhala, Y.V.I studied the temporal effect of grass harvest, burning, fertilizer, and grazing, with a factorial experimental design, in three grasslands of Royal Bardia National Park, Nepal. I tested the hypothesis of (i) nutrient depletion of grasslands by continuous harvest . and burning and (ii) differential use of areas by ungulates that were differentially managed m relation to forage quantity and quality. Addition of Di-ammonium phosphate and urea did not result in a significant increase in green above ground biomass and forage quality. Cut-burnt plots had the highest nutrient quality as indexed by crude protein and lignin. Plots that were only harvested had highest above ground biomass for the first month following harvest, and were more intensively grazed by ungulates during that time. Ungulates preferred to graze cut-burnt and burnt areas more during the second and third month following the treatment. Unmanaged tall grassland areas were also observed to have nutritive and other wildlife values. A management strategy for the grasslands of Bardia based on the above results is suggested. I compared the community structure, nutritive quality and above ground biomass of "grazing lawns" (patches of short grass communities), with neighboring grasslands. Grazing lawns differed form neighboring grasslands in species composition and community structure. A 50 day grazing free environment made areas of grazing lawns indistinguishable from neighboring grasslands in terms of above ground biomass. Grazing lawns had more nutritive forage in terms of digestibility and crude protein content. Sodium, magnesium and phosphorus were found to be below the critical requirements of ungulates. These minerals were ~found in higher concentrations in forages from grazing lawns. Grazing lawns seem to be maintained by continuous grazing and enriched by deposition of urine, dung and by certain plant species not found elsewhere in the neighboring grasslands.