PhD Theses (SACON)
Permanent URI for this collectionhttp://192.168.202.180:4000/handle/123456789/138
Browse
8 results
Search Results
Item 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 Ecology of elephants (Elephas maximus) and their interactions with humans in south West Bengal, India(SACON, 2023) Singh, Akriti; Kumara, H NThe thesis delves into the intricate dynamics surrounding the range expansion of Asian elephants in South West Bengal, catalyzing heightened human-elephant conflicts. It meticulously outlines the evolution of this phenomenon, starting from the elephants' modest presence in the 1950s to their expansive spread across 13200 km² by 2010–18. Through structured surveys and field observations, the elephants' footprint has been delineated across 163 grid cells in the region, showcasing their adaptability to varied habitat conditions. Central to understanding this expansion is the interplay between habitat factors and elephant presence. The thesis elucidates how the elephants' utilization of grid cells correlates positively with the forest edge, forest area, agricultural area, and barren land. As forests recede and agricultural land expands, elephants find themselves increasingly encroaching upon human settlements, leading to heightened conflict situations. Population estimation methodologies, ranging from dung count surveys to distance sampling, shed light on the elephant demographic in the region. However, the thesis highlights the challenges inherent in accurately gauging elephant numbers, particularly in areas where human activities disrupt their natural movement patterns. Despite these hurdles, the presence of a substantial number of immature elephants signifies a thriving population, albeit one grappling with human-induced disturbances. The thesis also sheds light to the ecological intricacies of elephant habitat use and feeding behavior. By overlaying grid cells on selected elephant habitats and analyzing geo-coordinates, the intensity of elephant habitat utilization was ascertained. The elephants' dietary preferences, encompassing a diverse array of wild plant species alongside agricultural crops, underscore their adaptive prowess in navigating human-altered landscapes. However, this dietary reliance on crops exacerbates conflicts, as elephants frequently venture into agricultural fields, triggering retaliatory measures from local communities.Item AVIFAUNAL COMPOSITION AND DISTRIBUTION PATTERNS ALONG ELEVATIONAL GRADIENTS IN THE SUTLEJ AND YAMUNA RIVER BASINS OF HIMACHAL PRADESH AND UTTARAKHAND, WESTERN HIMALAYA, INDIA(SACON, 2019) Shantakumar, B; Arun, P RUnderstanding the spatial difference in species diversity is a key challenge in ecology (Gaston, 2000). The well-known spatial pattern is the latitudinal diversity gradient, where species richness peaks at tropics and declines towards the poles (Rosenzweig, 1992). The richness of species along the elevational gradients is just a microcosm of the global latitudinal gradient (Rahbek, 1995). Species richness along the latitudinal gradient is the most striking and perhaps best-documented pattern (Yu et al., 2013). The complex elevational diversity of birds has been investigated on every continent (Cavarzere & Silveira, 2012). These patterns of species distribution along elevational gradients vary across taxonomic groups. Species richness patterns along the elevational gradients generally follow three patterns; 1) the monotonic decline of species richness, 2) the hump-shaped pattern with a peak at mid-elevation and 3) increase in species richness with increasing elevation (Figure 1.1). Among these, the first two patterns are the most common ones. i.e. either decreasing richness with increasing elevation or a hump-shaped pattern, in which diversity peaks at mid-elevations (Item Feeding Ecology and Social Structure of Golden Langur (Trachypithecus geei) in Secondary Forests of Chakrashila Wildlife Sanctuary, Assam, India(SACON, 2021) Shil, Joydeep; Kumara, H NI studied Golden langurs in altered habitats to understand the consequences of habitat conditions on social organization, ecology and ranging pattern. I selected 12 groups inhabiting forest edge and forest core of Chakrashila Wildlife Sanctuary and the adjoining rubber plantation. Three groups from the different habitats were also selected for activity budgeting and ranging data collection. Instantaneous scan sampling method was used and groups were followed from dawn to dusk. Geocoordinates of the group movements were recorded at every 30 minutes interval. The overall group size of golden langur was 11.3±3.5SD, and ranged between 5 and 18. The mean group size in forest core, forest edge and rubber plantation differed significantly. Births occurred in all the months but peaked between May and September (82.6%). The mean number of births positively correlated with mean monthly rainfall. Diurnal activities varied significantly with highest time spent on resting followed by feeding, locomotion, monitoring and social for all the three groups. The core group, edge group and rubber group spent 27.33%, 26.83% and 25.27% time in feeding respectively. Food items consumed varied significantly across the seasons and across the groups with highest leaf consumption of leaf annually by core group (65.67%), edge group (59.39%) and rubber group (34.60%). Number of plant species consumed by core group, edge group and rubber group are 39, 41 and 40 respectively. Mean annual day path length among the three groups have significant difference (F2,182=11.08, p<0.001). Home range area used by core group, edge group and rubber group are respectively 29 ha, 42.25 ha and 49.5 ha, however, the spatial use of the habitats by each group varied seasonally. It therefore, appears that social organisation, activity budget, diet and ranging pattern are related to disturbance and environmental factors. The behavioural parameters may influence life-history traits if continuous habitat alteration persists.Item Population Status and Resource Utilization of Nicobar long-tailed macaques (Macaca fascicularis umbrosus) in Nicobar Islands, India(SACON, 2021) Avdhoot, Velnkar D; Kumara, H NLong-tailed macaque (Macaca fascicularis) is one of the most widely distributed primates in east Asian countries. The subspecies of long-tailed macaque in India is M. f. umbrosus, which is endemic to three Nicobar Islands viz. Great Nicobar, Little Nicobar, Katchal. This study arose from the need to create baseline information for the isolated populations of the subspecies. I conducted a study on the ranging pattern, feeding habits, and activity budget of M. fumbrosus for my thesis. For population status and social organization the existing trails used in earlier studies were surveyed. Instantaneous scan sampling was followed for the data collection on activity budgets and feeding ecology. Geo-coordinates of the group were recorded every 30 min while following the group to assess the movement pattern and plot its home-range. The group encounter rate per kilometre in Great Nicobar (0.30) was significantly lower than in Katchal (0.48) with no difference between Little Nicobar (0.35) and the other two islands. The mean group size between Great Nicobar (39.83±17.47, N=6) and Katchal (43.50±26.15, N= 4) did not vary significantly. The population increased at an intrinsic rate (r) of 0.12, 0.14 and 0.17 in Great Nicobar, Little Nicobar and Katchal from 2006 to 2014. Throughout the day Resting was the most observed activity and foraging and scouting were the least observed activities. Activities feeding, social and movement occurred at similar proportion to each other through the day-time classes. Study group was observed to feed on 26 major food items of which 12 were introduced by humans and 14 were of native origin. Further seven extractive foraging and tool use behaviors were observed which include food extraction, foraging, food preparation and teeth flossing. females significantly fed on less coconuts compared to males despite showing equal proficiency in manipulation of all coconut types. ANOSIM performed between ages revealed that adults and immature were significantly dissimilar in their behavioral repertoire in processing coconuts. Markov chains for dry, mature and tender coconuts by adult and immature showed differences in behavioural transitions. A total of 830 group locations were collected during the study period, spread over in 66 grid cells of which 6 grids were used most frequently.Item Study of the Bird Community in Agasthyamalai hills, Western Ghats, Kerala, India(SACON, 2018) Panigrahi, Madhumita; Azeez, P Apatterns of occurrence or distribution and generality of the pattern (Weins 1989, Vellend 2010). A community is structured by wide array of factors, competition, niche availability, spatial heterogeneity, predation, climatic stability, productivity, dispersal, speciation and many more (Hutchinson 1959, Pianka 1966, Vellend 2010). On the other hand, distribution of species may be influenced by species composition, abundance, behaviour, morphology and their association with the environment (Weins 1989). Owing to the complexity of the systems and interactions among them, the study of community ecology is rightly stated by Schoener (1986) as the ‘most tumultuous and alluring of ecology’s subdisciplines’. Studies on avifauna have been playing a pivotal role in addressing intricate questions and testing varied hypotheses relating to community ecology. As widely noted, methodological advances, well-studied taxonomy and natural history, mostly diurnal behaviour and conspicuousness make birds an easy species to studyItem A STUDY ON REPRODUCTIVE BEHAVIOUR OF NICOBAR LONG-TAILED MACAQUE (MACACA FASCICULARIS UMBROSUS) IN NICOBAR ISLANDS, INDIA(SACON, 2018) Pal, Arijit; Kumara, H NNicobar long-tailed macaques (Macaca fascicularis umbrosus) live in three small isolated catastrophic prone Nicobar Islands. This study was conducted to understand the strategies adapted by these macaques to survive on such stressful condition, and compare it with other sub-species distributed in varying environmental conditions. The study suggested a high degree of similarities in demographic traits and social organization between the sub-species, which reflected the high adaptability of these macaques to manage the life-history traits by coping with the stressful condition. Contrasting to other sub-species, the distinct behavioral traits like the variation in age-sex ratio and non-seasonal breeding pattern in these macaques are the adaptive strategies to achieve the conservative life-history traits to maximize the reproductive output. Competition for mate resources was very evident in M. f. umbrosus, where individuals of both the sexes were involved in intra and inter-sexual competition to increase their reproductive success. Social hierarchy has a direct impact on the heterogeneous distribution of mate and food resources between individuals with different social status, which ultimately shapes the social organization in M. f. umbrosus. Consequently, to balance the disadvantages of living in such hierarchical group, individuals make a trade-off by adopting different behavioral strategies through policing specific inter-individual relationships. These macaques were involved in between-group contest to compete for food and mate resources rather than the territory defense. This study provided first-ever information about demography, social organization, reproductive behaviors, birth seasonality, and intra and inter-group competition in Nicobar long-tailed macaques. It also revealed that in due course of interactions with its environment, a species could become flexible with life history traits and adopt different strategies to increase survivability as well as inclusive fitness.Item Status and Ecology of House Sparrow Passer domesticus along an urban to rural gradient in Coimbatore, India(SACON, 2011) Dhanya, R; Azeez, P AIn due course of the evolution of human civilisation, from their nomadic to the resident lifestyle, they were industrious agents of change. Their behaviours changed ecological processes in agglomerates of residences and trades, in cities and as well as in other areas (Vitousek et al. 1997). As the human population rise, infrastructure grows up; urbanisation spreads and increasingly affects biodiversity (Blair 2004). Human activities in the form of land use changes, urbanisation and infrastructure developments are considered major threats to biodiversity (Gontier 2008). This in turn results in the loss and fragmentation of natural habitats, thereby threatening populations of local species and ultimately biodiversity (Saunders et al. 1991). Urban development produces the greatest local extinction rates and eliminates the majority of the species (Vale and Vale 1976, Marzluff 2001, Czech et al. 2000). This replacement brings in the process of biotic Homogenisation that threatens to reduce the biological uniqueness of local ecosystems (Blair 2001). The loss and fragmentation of valuable habitats influences the long-term viability of species populations, which may ultimately become extinct at the local or regional scale