PhD Theses (SACON)
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Item DIVERSITY AND DISTRIBUTION OF BIRDS IN BHARATHAPUZHA RIVER BASIN, KERALA(SACON, 2024) P N , Anoop Raj; Kumara, H NBharathapuzha also known as the Nila River is the second-longest river in Kerala. It is considered as one of the most important rivers in Kerala for its ecological, cultural, and historical importance. Thus, it is known as the cradle of civilisation in Kerala. This river originates from the northern and southern rims of the Palakkad Gap. It flows towards the west through the Coimbatore district in Tamil Nadu and the Palakkad, Thrissur, and Malappuram, districts of Kerala before draining into the Arabian Sea. The river's total length is 209 km with a drainage area of 6186 km2. Chitturpuzha, Kalpathipuzha Gayathripuzha, and Thoothapuzha are major tributaries of this river. Birds are considered as indicators of habitat quality. They play an important role as predators, prey, pollinators and scavengers in nature. Understanding the natural bird assemblage, its patterns, and its process will help prioritize the potential conservation areas. Many researchers have attempted to study bird communities in the different habitats in the Western Ghats. Their observations on birds provided useful information to understand the distribution trend of birds. Most of such studies focused on the forest ecosystems in the protected area network. Understanding the distribution pattern of birds and their drivers in highly disturbed ecosystems outside the protected area network is less attempted. From the origin to the mouth, the river passes through various ecosystems and topographic conditions. Bharathapuzha originates and runs through forest ecosystems in the Western Ghats hill ranges initially, then travels through various human habitations, and agrarian lands and finally reaches the Arabian Sea. So, it supports bird communities of different forest ecosystems, agrarian lands, water bodies, and human habitations including the urban areas. Most of these ecosystems are located outside the protected area network and are vulnerable to anthropogenic pressures. Deforestation in the hill region, construction of check dams, indiscriminate sand mining, the spread of weeds and invasive plants inside the river channel, expansion of monoculture plantations, encroachment and water pollution are the major threats to the river ecosystem. This study attempted to understand the patterns of avifaunal assemblage in the Bharathapuzha river basin which is highly disturbed due to anthropogenic pressures that destroyed the riverine habitats, water quality, and natural water flow.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 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 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 BURROW USE PATTERNS BY TERRESTRIAL VERTEBRATES IN KEOLADEO NATIONAL PARK, BHARATPUR, INDIA(SACON, 2018) Mukherjee, Aditi; Kumara, H NMost animals use some refuge either daily or seasonally. Burrow in terrestrial habitats is one of the oldest forms of engineered shelters (Voorhies, 1974) reported as early as carboniferous period (Olsen and Bolles, 1975). Burrows appear to be crucial refuge especially in arid and semi-arid regions providing protection against temperature extremes, fire and predation (Campbell and Clark, 1981; Reichman and Smith, 1990). Three major categories of burrowing vertebrates have been identified by Kinlaw (1999). These include ‘primary excavators’ for whom digging burrows is an inevitable part of their survival; ‘secondary modifiers’ that occupy and further transform the burrows of primary excavators and the third category of ‘simple dwellers’ that take advantage of the mere existence of the burrows and occupy them. Burrow inhabitants are even reported to be either in obligate and/or non-obligate commensal associations (Kiviat, 1978; Kinlaw, 1999). Burrowing vertebrates are the potential ecosystem engineers. These organisms have the capability of modifying habitats and directly or indirectly regulate resource availability for other species (Hansell, 1993; Jones et al., 1994; Lynn and Detling, 2008). They are known to have positive and negative effects on the ecosystem, species richness and abundance at small scales, but an overall positive effect at larger scales in ecological and evolutionary time and space (Jones et al., 1997). In Negev desert, Israel, the digging behavior of porcupine Hystrix indica has been studied as a model of disturbance and recovery of plant species (Gutterman et al., 1990). The burrows are important for newborn porcupines for their survival (decrease in vulnerability), energy conservation and thermoregulationItem STUDY OF POPULATION, ECOLOGY AND CONSERVATION OF LION-TAILED MACAQUE MACACA SILENUS IN SIRSI-HONNAVARA, WESTERN GHATS, KARNATAKA(SACON, 2015) Santhos, K; Kumara, H NTropical forests cover only 10% of earth’s area but inhabit ~50% of known species and higher number of unidentified species of the globe (Dirzo and Raven 2003). These forests face severe challenge in the recent decades due to everlasting pressure from human activities (Whitmore and Burslem 1998). About 60% of tropical forests were classified as degraded by the year 2000 (ITTO 2002). Degradation of tropical forests are mainly due to land use changes escalated by agricultural expansion, commercial logging and plantations, mining, industrial development and urbanization (Geist and Lambin 2002). Thus, these land use changes are responsible for biodiversity loss (Sala et al 2000). Tropical forests have historically been exploited for sufficing to the needs of development (Gibson et al 2011). This has resulted in elimination of native flora and altering the stand characteristics of the forests (Gadgil and Chandran 1989). These changes have also altered the microclimate (Johns 1985), and thus responsible for colonization of invasive plant species (Malcolm et al 2000). They have rapidly affected the dependent fauna of the area, of especially vertebrates which are highly endemic and habitat specific