Theses and Dissertations

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Author: search.filters.author.Kumar, AjithSubject: search.filters.subject.Mammals

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    IMPACTS OP HABITAT FRAGMENTATION ON THE TERRESTRIAL SMALL MAMMAL COMMUNITIES IN THE TROPICAL RAIN FOREST OP THE ANAIMALAI HILLS IN THE WESTERN GHATS, SOUTH INDIA
    (SACON, 1998) Prabhakar, A; Kumar, Ajith
    The loss and fragmentation of the species-rich tropical rain forests is the most serious conservation crisis currently facing us. In the Western Ghats in south India as much as 40% of the forests was lost between 1920s and 1990s, with a 17-fold increase in forest patches. Such fragmentation of forests leads in the long run to loss of species due to the problems faced by small isolated populations, the cascading effects of the changes in the micro and macro climate, and the effects of invading species. The goal of this study was to make an assessment of the changes in the small mammal community due to the fragmentation of their rain forest habitat in the Western Ghats. The study animals included rodents of the Families Muridae and Muscardinidae, and shrews of the Order Insectivora. The specific objectives were: (a) to evaluate the differences among rain forest fragments in the community structure of small mammals, in relation to macrohabitat features of the forest fragments; (b) to examine the synchrony among forest fragments in the seasonal variation of several demographic parameters; and (c) to identify species differences in microhabitat preferences and examine their relevance to the changes in community structure due to habitat fragmentation.
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    IMPACTS OF HABITAT FRAGMENTATION ON THE ARBOREAL MAMMALS IN THE WET EVERGREEN FORESTS OF THE ANAMALAI HILLS IN THE WESTERN GHATS, SOUTH INDIA
    (SACON, 1998) Umapathay, G; Kumar, Ajith
    Habitat fragmentation is the most severe threat to biological diversity and is the primary cause of the present species extinction crisis. Small populations in fragments are highly prone to extinction due to demographic and evironmental stochasticity, disease and catastrophes. Long term degeneration of habitat might also add to this extinction. In south India, wet evergreen (or rain) forest is confined to the Western Ghats mountains. Human activities such as plantations of tea, coffee, teak, etc., and construction of roads, railways, and reservoirs during the last two centuries have led to extensive loss of these forests. More importantly, the remaining forest has been severely fragmented. The impact of forest fragmentation is expected to be particularly severe among the arboreal mammals due to loss of arboreal connectivity between forest fragments. In this background, the objectives of this study were; 1) To assess the extent to which arboreal mammals disappear from wet evergreen forest fragments with respect to various landscape and habitat parameters associated with forest fragmentation; 2) To identify changes in their activity pattern and feeding ecology; 3) To examine changes in demographic parameters of these species in relation to habitat fragmentation; and 4) To examine species differences in their response to forest fragmentation and to suggest appropriate measures to enhance the survival of arboreal mammals in forest fragments.
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    Food Availability and range use by the common langur (Presbytis entellus) in Rajaji National Park, U.P. India
    (1991) Tiwari, Geetanjali; Kumar, Ajith
    A bisexual group of Common langur (P. entellus) wan chosen in Rajaji national Park, (U.P. India) to tent my hypothesis that spatial variation in the intensity of use -of home range is correlated with food availability. During the study period T collected data at three levels: (i) 6-day group scan for activity patterns, occupational density and frequency of use of major food species items. (ii) Circular plots, covering 6 percent of the area for estimating availability of tree species. (iii) Phenological data for estimating monthly variation in food items. Using the latter two I calculated the availability of major food species item spatially and temporally. I found that occupational density was significantly correlated with the availability of major food items in only two months. When analyzed for five months correlation increased as more major food items were added. The correlation was not significant for December, February and March because of constraints in the estimation of food availability added to the problem of dumpiness and rarity in the distribution of food species. A linear correlation is however, unlikely because availability of most foliage is often in excess of immediate requirement. moreover, as summer progressed water increasingly became limiting factor. This, in combination with other factors like inter-group interactions might further decrease the possibility of getting a linear correlation.
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    Leaf Chemistry and Food Selection by the Common Langur (Presbytis entellus, Dufresne 1797) in Rajaji National Park U.P. India
    (1991) Gupta, Kaberi Kar; Kumar, Ajith
    Food selection in folivorous primates has been hypothesised to be correlated with leaf chemistry. To test this hypothesis, a 5- month study on Presbytis entellus was carried out in a moist deciduous forest in the Rajaji National Park, U.P. Two indices of food selection were estimated: percent time spent feeding on the food item, and selection ratio. The former was estimated from group scan data collected from one study group for six days each month. The selection ratio for each item was estimated as a ratio of time spent feeding to availability. Food availability was estimated from vegetation sampling, which covered 6% of the home range of the study group, and phenology data in the study area. Crude Protein (CP), Acid Detergent Fibre (ADF) and Tannins in mature and young leaves of 12 major food species were estimated in the laboratory. Food selection was positively correlated with CP in winter and with ADF in both seasons. It was also correlated with CP/ADF ratio, but to a lesser extent than the best predictor in winter and spring. Selection ratio did not have any correlation with CP in two seasons and only a weak correlation with ADF» It is very likely that the inclusion of other factors such as micro-nutrients, condensed tannins and digestibility might give a better prediction of food selection.