PhD Theses (SACON)

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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.
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
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.
A STUDY OF THE ECOLOGY OF SELECT SPECIES OF WEEDS IN DIFFERENT VEGETATION TYPES OF NILGIRI BIOSPHERE RESERVE
(SACON, 2000) Mahajan, Maya V
Invasion by weedy species of plants has serious impact on natural and managed ecosystems. Weedy species invade agricultural lands, fallow lands, roadsides, disturbed forests and plantations. Invasion by such species modifies the ecosystem structure and function. Invading species may dominate and displace the native vegetation and cause extinction of certain native species, leading to alteration in the original biodiversity of an area. In recent years, biological invasion is being recognized as a serious threat to biodiversity conservation
SEASONALITY AND ABUNDANCE OF INSECTS WITH SPECIAL REFERENCE TO BUTTERFLIES (LEPIDOPTERA: RHOPALOCERA) IN A MOIST DECIDUOUS FOREST OF SIRUVANI, NILGIRI BIOSPHERE RESERVE. SOUTH INDIA
(SACON, 2000) Arun, P R; Vijeyan, V S
The present study describes the seasonal variations in the abundance of insect groups in a natural moist deciduous forest of Western ghats, South India. The study covers the seasonal abundance patterns of six major insect orders, namely Coleoptera, Lepidoptera, Hemiptera, Diptera, Orthoptera, and Hymenoptera and also the seasonality of 53 species of butterflies (Lepidoptera; Rhopalocera). The relationship of insect abundance with the prevailing abiotic and biotic conditions has been examined. Three major sampling methods, namely sweep sampling, knockdown sampling and light trapping were used for the general insect sampling, while transect counting method was employed for the estimation of butterfly abundance. Other methods involving direct and indirect visual estimation of insect abundance employed in the field in an experimental basis for relatively shorter durations are also described.
ECOLOGY AND UTILIZATION OF MEDICINAL PLANTS WITH SPECIAL REFERENCE TO SELECT TRIBAL GROUPS IN THE NILGIRI BIOSPHERE RESERVE
(SACON, 2000) Rajshekharan, A; S, Narendra Prasad
Forest dwellers have been using the plants around their settlements to treat their health ailments since time immemorial, the knowledge of which was obtained from their ancestors orally. However, in recent years such traditional knowledge is getting depleted among tribal groups, due to cultural westernisation, industrialisation, urbanisation and rapid loss of their natural resource base. Traditionally, the tribals extracted medicinal plants for sustenance and local sales. But, increasing commercialisation has lead to over-exploitation of medicinal plants resulted in the reduction of the population of these species. Although, there is considerable evidence for over-harvesting of medicinal plants, quantitative data on the effect of extraction on natural populations are very few. Moreover, information on density, population structure and the resource base for future utilization is unknown for most extractive reserves.
A study of the ecology of select species of weeds in different vegetation types of Nilgiri Biosphere Reserve
(SACON, 2000) Mahajan, Maya V; Azeez, P A
Invasion by weedy species of plants has serious impact on natural and managed ecosystems. Weedy species invade agricultural lands, fallow lands, roadsides, disturbed forests and plantations. Invasion by such species modifies the ecosystem structure and function. Invading species may dominate and displace the native vegetation and cause extinction of certain native species, leading to alteration in the original biodiversity of an area. In recent years, biological invasion is being recognised as a serious threat to biodiversity conservation (Pimm and Gulpin 1989, Vitousek et al. 1996). In contrast to studies in agricultural fields, not much attention is given to plant invasion in natural ecosystems. Nevertheless, the colonisation of natural forest ecosystem by weedy species is growing as a threat. In recognition of the threats posed by plant invasions in natural vegetation and realising the scarcity of ecological information on various colonising plant species
A study on the breeding biology of the Nicobar Megapode Megapodius nicobariensis
(SACON, 2000) Sivakumar, K; Sankaran, Ravi
The family Megapodiidae consists of 22 species in seven genera, most of which are island forms occurring in Australia, New Guinea and surrounding islands, eastern Indonesia, the Philippines, Niuafo’ou island, the Palau and Mariana islands and the Nicobar islands. Thirteen of these 22 species are currently threatened by habitat destruction, introduction of predators and over-exploitation of eggs. The megapodes are an unique group of birds as they utilise external sources of heat to incubate their eggs. Megapodes exploit external heat sources in two ways. Some species lay eggs in burrows in geothermally heated soil, or on exposed beach, and are called burrow nesters (e.g. Macrocephalon maleo). Other species construct mounds of sand, soil and decomposing vegetation within which they lay eggs and are called mound nesters (e.g. Megapodius freycinet). The chicks are supra-precocial; they are able to fly soon after emerging from the mound or burrow, and receive no parental care.
Ecology of the brown palm civet Paradoxurus jerdoni in the tropical rainforests of the Western Ghats, India
(SACON, 2001) Mudappa B, Divya Cauvery; Kumar, Ajith
The 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.
Habitat utilization by Malabar Grey Hornbill at Mudumalai Wildlife Sanctuary, Western Ghats. (TH12)
(SACON, 2002) Maheswaran, B.; Balasubramanian, P.
Utilization of habitat resources, particularly fruit and nest trees, by an endemic bird species, Malabar Grey Hornbill (Ocyceros griseus) was studied in a tropical semi-evergreen forest and the adjoining tea/coffee plantations at Mudumalai Wildlife Sanctuary, Western Ghats. This bird species is mainly distributed in the moist forests of southern Western Ghats. Though some aspects of Malabar Grey Hornbill in an evergreen forest at Anamalai Hills have been studied during the breeding season, fruit utilization during the non-breeding season is not known. Also, the preference of this endemic hornbill for food and nest tree species is unknown. This study aimed to assess the food preferences of Malabar Grey Hornbill during breeding and non-breeding seasons, nest-tree preferences and to identify the keystone resources for the Malabar Grey Hornbill in the semi-evergreen forest.
Phyto-Ecology, Lion-Tailed Macaque, Macaca Silenus, Habitats, Southern India
(SACON, 2002) Krishnamany, R; Kumar, Ajith
The 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
Ecology of Bird Communities in the Anaikatty Hills, Coimbatore”
(SACON, 2002) Nirmala, T; Vijayan, Lalitha
Structural and functional aspects of bird communities are believed to have direct relation with the structure of habitat and thereby act as indicators of environmental changes. Various components such as the type of resource, quantity of resource and spatial and temporal distribution of resources play a major role in determining the community structure. In general, the central theme in the functional aspects of the avian community studies has been, how the available resources for biological activities such as foraging, roosting and nesting are partitioned among the existing group of species. Studies on bird community in different habitats are very few in India, and the pattern and processes of a group of species or an individual species were studied separately. The study of birds in relation to habitats will give valuable data for forest management. Area outside protected area network is also equally important for birds and biodiversity conservation. This study was designed to determine the ecology of the bird communities in the mixed dry deciduous forest and scrub forest (SACON) in Anaikatty Reserve Forest, foothills of Nilgiri Biosphere Reserve, Coimbatore, South India.
PHYTO-ECOLOGY OF THE LION-TAILED MACAQUE (Macaca silenus) HABITATS IN SOUTHERN INDIA
(SACON, 2002) KRISHNAMANI, R; Kumar, Ajith
The 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.
Air Quality of Coimbatore with Emphasis on Respirable Suspended Particulate Matter
(SACON, 2002) Mohanraj, R; Azeez, P A
Particulate matter (PM), a complex mixture of organic and inorganic substances is an ubiquitous air pollutant, contributed by both natural and anthropogenic sources. Ever since the advent of industrial era, anthropogenic sources of PM have been increasing rapidly. Increasing amounts of such potentially harmful particles being emitted into the atmosphere on a global scale has resulted in damage to the health and environment. Recently it is also reported that soot particles have a heating effect to the atmosphere. Such heating effect can have wide implications on various systems of earth including climate. PM in the atmosphere is categorized according to size because of different health impacts from particles of different diameters. PM with diameters of less than 50 pm are generally classified as Total suspended Particulate Matter (TSPM). Particles that are greater than 50 pm in diameter do not remain in the atmosphere for appreciable lengths of time and present no health risk. Particulates with a diameter less than 10 pm defined as PM 10 or Respirable Suspended Particulate Matter (RSPM), enter the respiratory system and may become lodged in the alveoli resulting in wide range health effects including cancer and heart failures. PM 10 has the potential to travel long distances and cause cumulative effects. Other hazardous air pollutants may adhere to these particles, increasing their toxicity. These particles on wet and dry deposition are known to pollute local, regional and global land and water resources.
POPULATION AND RESOURCE UTILISATION BY REPTILES IN UPPER NILGIRIS, NILGIRI BIOSPHERE RESERVE, WESTERN GHATS, INDIA
(SACON, 2005) ARMSTRONG, A. MATHEWS NIXON; Bhupathy, S
Herpetofauna (reptiles and amphibians) are important components of both terrestrial and wetland ecosystems as they play a major role in energy flow and nutrient cycling. Both of them are also excellent indicators of environmental degradation. Being poikilotherms, reptiles tend to partition time and space more often than homeotherms as their physiology and behaviour are closely linked to environmental conditions. However, quantitative data on the population and resource use by reptiles are scanty in India. Resource use can be studied with respect to the three most often recognized niche axes: spatial (habitat use), temporal (activity period) and trophic (food). Herpetofauna of India, one of the most diverse taxa, is poorly known regarding their ecology and population characteristics. Major objectives of this study was to (1) assess the population status of reptiles and factors determining their distribution in various habitats of Upper Nilgiri plateau (2) determine the habitat use and food habits of reptiles, and (3) to understand the resource use at spatio-temporal and trophic levels by reptiles in Upper Nilgiris.
Status and ecology of the Nilgiri Wood Pigeon in the Western Ghats
(SACON, 2006) Soumasunderam, S.; Vijayan, Lalitha
Conservation of the species requires a comprehensive picture on the status and distribution, ecological requirements for feeding, breeding and other activities. Ecological studies on most of the endemics have not yet been conducted and hence, such information is not available for any management programmes. Moreover, human impacts on the habitats of most species are also not understood. Hence, the present study was conducted on an endemic, endangered species of the Western Ghats which is considered as Globally Threatened, the Nilgiri Wood Pigeon Columba elphinstonii, addressing mainly its biological and ecological requirements.
Ecological studies of insect communities in Anaikatty hills
(SACON, 2006) Eswaran, R.; Pramod, P.
Community studies are relatively less in ecological entomology. Documentation of the communities of insects itself is a challenging job because of the inherent weakness in taxonomical brevity at the special level. The present study aimed primarily at exploring the patterns of insect diversity of a dry deciduous forest of Anaikatty hills, Western Ghats. As the term insect holds a large spectrum of organisms with a great level of taxonomic ambiguity, new approaches are needed to face the problems related with its diversity and distribution. The new approach attempted in this study was to examine the dynamics of diversity and abundance at different levels. At the broadest level an attempt has been made to study the composition and changes of insect families within and between different microhabitats of the landscape. At the intermediate level, the species composition, diversity and dynamics of one selected group of insects, viz., butterflies and at a finer level the aggregation and dynamics of the individuals of the selected species of butterflies were studied. The abiotic and biotic influences of these family levels, species level and individual level patterns were also studied
Resource utilization patterns of reptiles in the Tropical Dry Mixed Deciduous Forest of Anaikatty Hills, Western Ghats, India.
(SACON, 2007) Mukherjee, Debanik; Bhupathy, S.
The western ghats is one of the 34 globally recognized biodiversity hot spots. Among the 506 species of reptiles reported distributed in India 165 are distributed in the Western ghats. The concept of a biotic community may be defined as tn assemblages of various organisms living together and interacting at all trophic levels. The present study was undertaken with the following objectives (1) to know the suitability of various techniques for sampling reptiles in tropical mixed dry forest (2) To study aspects of population of reptiles in the Anaikatty hills in terms of species richness, diversity and relative abundance (3) to understand the patterns of resource use by reptiles at various spatio-temporal level.
Status and Ecology of the Nilgiri Pipit in the Western Ghats.
(SACON, 2007) Vinod, Uma J.; Vijayan, Lalitha
Study was undertaken on the Nilgiri Pipit with the following main objectives a) determine the status b) unravel the ecology c) identify the key factors affecting the survival of the Nilgiri Pipit and suggest management options
Studies on Taxonomy, Ecology, Distribution and Conservation values of Sthalavrikshas (Temple Plants) in Tamil Nadu, South India
(SACON, 2007) Gunasekaran, K.; Balasubramanian, P.
A review of previous studies in this field reveals that the information is found scattered. Only a handful of scholars have conducted research in Ulis field and that too based on medicinal, religious and mythological literature. Hence, a systematic study is felt as the need of the hour with the following objectives.1. To conduct taxonomic survey of s tha1avrikshas and bring out an authentic list of sthala vrikshas of Tamil Nadu. 2. To assess the ecological importance and conservation values of sthalavrikshas. 3. To document the role of traditional customs and beliefs of sthalavriksha worship in conserving the botanical resources. Tamil Nadu s tale along with union territory of Puducherry comprises the study area. Tamil Nadu (8" 5' and 13° 35' N Latitude and 76° 15' and BOO 20' E Longitude) is situated in the southern part of peninsular India. Tamil Nadu has wide range of land forms such as Coast, Plains and Ghats and is often known as the land of temples. There arc about 25,000 temples in the state.