PhD Theses (SACON)

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End date: 1999

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    BIRD COMMUNITIES OF THE THORN AND DRY DECIDUOUS FORESTS IN MUDUMALAI WILDLIFE SANCTUARY, SOUTH INDIA
    (SACON, 1998) Gokula, V; Vijayan, Lalitha
    Birds are important components of forest ecosystem, playing a major role as pollinators, consumers and dispersers of plant seeds, and predators of insects. In nature different species form intricate assemblages as a result of the local ecological make up. Whittaker (1975) states that communities are assemblages of populations of species which occur together in space and time. Studies on bird community ecology starting from MacArthur and MacArthur(1961) have attracted wide attention. The main focus of community ecology is the manner in which groupings of species are formed and distributed in nature and the ways in which these can be influenced or caused by interactions between or among the species and the physical and biological factors of their environment. The cause-effect relation of such assemblages led to an increased interest in studies on bird communities (Cody, 1974; Cody and Diamond, 1975). An understanding of the determinants of bird community structure is extremely important for the practical development of guidelines for the habitat management
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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.