PhD Theses (SACON)

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Ecology of elephants (Elephas maximus) and their interactions with humans in south West Bengal, India
(SACON, 2023) Singh, Akriti; Kumara, H N
The 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.
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 N
I 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.
Population Status and Resource Utilization of Nicobar long-tailed macaques (Macaca fascicularis umbrosus) in Nicobar Islands, India
(SACON, 2021) Avdhoot, Velnkar D; Kumara, H N
Long-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.

PhD Theses (SACON)

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