PhD Theses (SACON)
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Item Phyto-Ecology, Lion-Tailed Macaque, Macaca Silenus, Habitats, Southern India(SACON, 2002) Krishnamany, R; Kumar, AjithThe causal factors for the very high species diversity in tropical rainforests have been the focus of ecological research for several decades. It has become obvious that the high tropical species diversity has three major components, local (often called α-diversity), regional (β-diversity), and landscape (γ-diversity). Contribution of each of these components to overall diversity might vary from place to place, and from taxon to taxon. The pattern of variation in plant diversity is of particular interest since this would have a profound impact of the distribution and abundance of secondary consumers. In this study, I examine the nature and extent of spatial variation in the species diversity of woody plants in the rainforest of the Western Ghats Mountain ranges in south India, one among the eight most threatened biodiversity hotspots of the world. I also examine whether the diversity of food trees of the lion-tailed macaque (Macaca silenus), an endemic to the tropical rainforest of the Western Ghats and phylogenetically the ancestor of all extant Asian macaques, also show variation at different spatial scales that is similar to that of all wood plants. Since the phenology of plants also affects the secondary consumers, this issue is examined at one siteItem Ecology of the brown palm civet Paradoxurus jerdoni in the tropical rainforests of the Western Ghats, India(SACON, 2001) Mudappa B, Divya Cauvery; Kumar, AjithThe small carnivores of the mammalian Families of Viverridae, Herpestidae, and Mustelidae play very important roles in tropical rainforest ecosystems, as predators, prey, and seed dispersers. These roles have been poorly studied, even as small carnivore communities are undergoing changes due to severe loss and fragmentation of rainforests. This thesis explores the ecology of a small carnivore, the brown palm civet (Paradoxurus jerdoni Blanford 1885), endemic to the rainforests of the Western Ghats hill ranges of India, and also examines changes in the structure of the terrestrial and arboreal small carnivore community as a whole, due to rainforest fragmentation. The ecology of the brown palm civet, an endemic and nocturnal viverrid, was examined with reference to its role as a seed disperser, and the factors governing its diet composition, and ranging and activity behaviour, in the relatively undisturbed, large tract of rainforest in the Kalakad-Mundanthurai Tiger Reserve (KMTR), between May 1996 and December 1999. The small carnivore community here was compared with that in the rainforest fragments of the Anamalai Hills that were surveyed between January and May 2000. Habitat correlates of the occurrence of small carnivores were also examined.Item 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, AjithThe 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.Item 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, AjithHabitat 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.Item PHYTO-ECOLOGY OF THE LION-TAILED MACAQUE (Macaca silenus) HABITATS IN SOUTHERN INDIA(SACON, 2002) KRISHNAMANI, R; Kumar, AjithThe causal factors for the very high species diversity in tropical rainforests have been the focus of ecological research for several decades. It has become obvious that the high tropical species diversity has three major components, local (often called α-diversity), regional (β-diversity), and landscape (γ- diversity). Contribution of each of these components to overall diversity might vary from place to place, and from taxon to taxon. The pattern of variation in plant diversity is of particular interest since this would have a profound impact of the distribution and abundance of secondary consumers. In this study, I examine the nature and extent of spatial variation in the species diversity of woody plants in the rainforest of the Western Ghats mountain ranges in south India, one among the eight most threatened biodiversity hotspots of the world. I also examine whether the diversity of food trees of the lion-tailed macaque (Macaca silenus), an endemic to the tropical rainforest of the Western Ghats and phylogenetically the ancestor of all extant Asian macaques, also show variation at different spatial scales that is similar to that of all wood plants. Since the phenology of plants also affects the secondary consumers, this issue is examined at one site. Although the Western Ghats mountain ranges extend over 1600 km, from 8°-21° N, this study was restricted to the tropical rainforest between 8°30’ and 14°17’ N within an altitudinal range of 100-1500 m, which formed the habitat of the lion-tailed macaque. The rainforest north of this is also heavily disturbed and highly fragmented. The variation in the woody plant community was examined primarily with reference to their species richness, density, and basal area.