M Sc Dissertation(WII)
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Item Food Resource Partitioning Among Sympatric Bovids Chinkara, Blackbuck and Nilgai in Rajasthan Desert(Wildlife Institute of India, Dehradun, 1989) Kunhunu, N.V.Ashraf; Goyal, S.P.Patterns of dietary selection, overlap and spatial distribution were investigated for three species of sympatric wild ungulates and four species of domestic ungulates (goat, sheep, camel and cattle> during four seasons (summer, pre monsoon, monsoon & post monsoon) in Rajasthan desert. The objective was to determine the mechanisms of food resource partitioning among these seven species of ungulates and the factors allowing their coexistence. Two study areas, Dhawa-Doli and Janwar-Doli were selected for the study, based on the density and distribution of the three wild ungulates. More emphasis was given to Dhawa-Doli where two of the three species (chinkara & blackbuck> were common. Food habits were studied by direct observations. Feeding activity was recorded for feeding height, plant species and part eaten. Availability was determined by percentage cover classes. Three major vegetation zones were identified at Dhawa-Doli. Six study sites were selected across the three vegetation zones. Blackbuck were primarily grazers in monsoon when crops were beginning to grow and annual plants were abundant. Chinkara and nilgai browsed throughout the study and did not show any preference for monocots in periods of resource abundance (monsoon and post monsoon). Food habits of wild ungulates differed more between zones in summer and pre monsoon, when resources were limiting and the effect of vegetation zonation on food habits was evident. In monsoon and post monsoon when resources were abundant, the effect of vegetation zonation was negligible as opportunity for selection increased. Though dietary similarity was more in terms of plant species eaten between chinkara and goats and between sheep and blackbuck, they differed greatly in proportion of utilization. Greater overlap between chinkara and blackbuck during premonsoon suggest a possible temporary interspeciflc competition. In scrublands, dietary overlap was more between species with similar feeding strateg1es (goat & chinkara - sheep & blackbuck) and was less between species with dissimilar feeding strategies. Nilgai was spatially separated in summer and pre monsoon and showed a seasonal spatial overlap w1th chinkara and blackbuck at Dhawa-Doli during crop season. While blackbuck and nilgai exhibited a spatial divergence in response to temporal and spatial availab1lity of food resources, chinkara was largely sedentary. Though utilization of different habitat subun1ts (crop fields, cultivated fields and scrublands) were largely determined by the amount of disturbance, ch1nkara showed a random utilization of these subunits. Blackbuck showed a slight avoidance for crop fields, at least at day time, even though they consumed more crops than chinkara. Mean feeding height for domestic ungulates decreased towards post monsoon as they spent more time feeding on annuals. However, the mean feeding height for wild ungulates increased in response to the growth form of plants. The difference in utilization of different foraging strata was more evident between browsers and more similar between grazers. Broadly, this study suggests that dietary differences among all species were more important than spatial differences, in food resource partitioning.