M Sc Dissertation(WII)

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    Factors Influencing Small Carnivore Community Structure in Chandoli National Park Northern Western Ghats
    (Wildlife Institute of India, Dehradun, 2019) Lad, Himanshu C.; Gopi, G.V.
    The current study was conducted on small carnivores in Chandoli National Park of Sahyadri Tiger Reserve from December 2018 to April 2019. The main objectives was to understand drivers of spatial distribution and temporal variation amongst sympatric small carnivores present in the study area. This study provided information on local small carnivore distribution, dietary pattern of palm civet and time activity patterns of small carnivores in Chandoli national park
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    Evaluating the importance of scale in estimating tiger populations
    (Wildlife Institute of India, Dehradun, 2007) Contractor, Deep; Jhala, Y.V.; Qureshi, Qamar
    Population estimation is one of the most important aspects of ecological studies as it plays a pivotal role in establishing priorities for species specific conservation and for delineating management practices. The tiger serves as a flagship and umbrella species for conservation efforts in the Indian subcontinent but, unfortunately wild tiger populations are on a drastic decline owing to factors like poaching, habitat fragmentation and degradation. In such a scenario reliable population estimates prove to be of vital importance. Camera trapping technique has been widely used for population estimation of cryptic carnivores including tigers. An attempt was made, through this study, to arrive at population and density estimates for Corbett NP through camera trapping technique following the mark recapture framework and answering some key questions regarding the importance of sampling effort required for arriving at such reliable estimates. A total of 7865 trap nights yielded 358 captures of 103 individual tigers within an intensively sampled area of (MCP) 420.86 km2. The estimated density of tiger was 16.01 (±1.6) per 100 km2 for RPSV, a new approach to calculate effectively sampled area. These estimates coincided with the estimates using full MMDM method. Also, the conventional method of using half MMDM seems to overestimate the density. The estimated sampling effort required for arriving at accurate and precise estimates of the true population in terms of sampling occasions amounted to 35 - 40 days. Evaluation of the influence of trap density revealed that high trap density (25 traps/km2 ca.) is required to get reliable estimates of population irrespective of the underlying population/density gradient.
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    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 estimation