Theses and Dissertations
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Item Ecology of major Invasive Alien plant species (IAPs) across various habitats in Pakke Tiger Reserve, Arunachal Pradesh(Wildlife Institute of India, Dehradun, 2026) Singh, Huidrom Bablin; Adhikari, B.S.Proliferation of invasive alien plant species poses a significant threat to the structure and function of ecosystems, making this a critical area of focus within the scientific communities. These species cause extensive damage to the biodiversity, as they are capable of altering the ecosystems and outcompete the native biodiversity. Globally, their abundance has increased dramatically in forested and other natural areas due to rapid economic growths and anthropogenic activities. To counter this alarming situation, understanding the distribution pattern, climatic influences on phenophases and ecological impact on soil by invasive alien plant species is a priority. In northeast India, studies on invasive alien plant species diversity and their impacts are very limited, especially in Arunachal Pradesh. Therefore, the present study aims to determine the patterns of distribution, phenophases and physiochemical impacts by the dominant invasive alien plant species in five forest types (Assam Alluvial Plain Semi Evergreen Forest-AAPSEF, East Himalayan Mixed Coniferous Forest-EHMCF, East Himalayan Subtropical Wet Hill Forest-EHSTWH, Non-Forest-NF and Riverine Forest-RF) of Pakke Tiger Reserve, Arunachal Pradesh. The altitudinal range of Pakke Tiger Reserve is 150- 2050 m above the sea level (490 to 6725 feet), with an average annual rainfall of 2500 mm. The current study reveals a total of 43 invasive alien plant species in the study area. However, their species richness in five forest types was in declined trend with the increase of elevation. Across the forest types, AAPSEF (30%) display the maximum level of invasion and least incursion in EHSTWHF (16%) in the current study. Among the nine species selected for the study, Chromolaena odorata (L.) R.M.King & H.Rob. was found dominant and distributed extensively in all forest types, with highest relative density (51%) in EHSTWHF and relative abundance (10%) in NF. The entire selected species shows contagious distribution pattern (<0.5) in all forest types except for Urena lobata in NF displaying random distribution (0.025 - 0.5) in study area. Ageratum conyzoides L., Chromolaena odorata (L.) R.M.King & H.Rob. and Urena lobata L. are the species with extensive distribution in all forest types in comparison to other selected species showing their dominance over the native vegetation. Moreover, maximum area cover percentage was exhibit by Chromolaena odorata (L.) R.M.King & H.Rob. followed by Ageratum conyzoides L., Mikania micrantha Kunth and Urena lobata L. across the forest types in Pakke Tiger Reserve. Forest types such as AAPSEF, NF and RF display high level of disturbances while the EHMCF and EHSTWHF have fewer incursions by invasive alien plant species in the study area. Phenological pattern on the selected species shows that Bidens pilosa L. has the longest flowering phenophases while Chromolaena odorata (L.) R.M.King & H.Rob. has the maximum fruiting duration in EHSTWHF. For leaf fall and initiation, Urena lobata L. display the longest duration in RF. Moreover, coefficient of variation shows that most of the species display asynchronous phenophases across the forest types of Pakke Tiger Reserve. Repeated measures of ANOVA also display that Ageratum conyzoides L. display difference in flowering in NF and EHSTWHF while Chromolaena odorata (L.) R.M.King & H.Rob. leaf initiation show difference in EHMCF. Correlation and linear regression display influences of climatic parameters i.e., precipitation, relative humidity, minimum and maximum temperature to the selected species in the study area. CCA also indicates that precipitation, minimum and maximum temperatures directly influence the phenophases of the selected species. However, relative humidity influences the phenophases of the selected species when in cohesion with other climatic parameters. Ecological impact on native species by invasive alien plant species was determined by collecting the soil sample of the most dominant species i.e., Chromolaena odorata (L.) R.M.King & H.Rob. across the forest types in Pakke Tiger Reserve. The result shows that clay and copper contents were high in all invaded sites while soil pH, sand, boron and water holding capacity were significantly lower in invaded plots. Out of 16 soil variables, T-test reveals that AAPSEF and NF have variation in 13 variables while EHMCF, EHSTWHF and RF have difference in 12 variables. ANOVA between the invaded and uninvaded sites also indicates significant differences in Boron, iron, copper, nitrogen, water holding capacity, clay, silt and sand. Moreover, correlation shows eight of the variables display relation between them. Furthermore, PCA indicates that INNF soil properties were different from the remaining sites. The results indicate that Chromolaena odorata (L.) R.M.King & H.Rob. alter the soil properties of invaded areas by improving the fertility, making it ideal for the proliferation process in future scenarios.Item Distribution of major alien invasive plants and impact assessment of Ageratina adenophora (Spreng.) K & R. in Kailash Sacred Landscape, Uttarakhand(Wildlife Institute of India, Dehradun, 2022) Chaudhary, Alka; Adhikari, B.S.; Rawat, G.S.The study was conducted to assess the spread, distribution, impact of invasion in Indian part of Kailash Sacred Landscape (KSL) characterized by interspersion of human habitations, extensive forest managed by the State Forest Department and local community institutions (Van Panchayat). The objectives of the study were (i) To model spatial distribution of selected plant invasive species using distribution modeling technique. (2) To assess the impacts of IAPs on native flora and relationship with habitat parameters (3) To analyze people's perception towards the spread of IAPs in KSL India landscape (4) Experimental trials on Eco restoration of habitats and prediction of future spread for better managementItem Habitat, food resource utilization of Himalayan brown bear (Ursus arctos isabellinus, Horsfield 1826) and conflict with humans in Lahaul valley, Himachal pradesh(Wildlife Institute of India, Dehradun, 2023) Kumar, Vineet; Adhikari, B.S.; Sharma, Lalit KumarHimalayan brown bear (Ursus arctos isabellinus) is one of the top carnivores dominating the higher altitudes of the North and Western Himalayan landscape. In India, based on the 2005 estimate the approximate brown bear distribution range is reported to be 36,800 km2 , whereas only 10% of the total distribution area of the brown bear comes under the protected areas. There is very low density of brown bear lies in its distribution range throughout the Western Himalaya, in alpine meadows, scrub and sub-alpine forests of two Union Territories (Jammu and Kashmir; and Ladakh) and two Indian Himalayan States, Himachal Pradesh and Uttarakhand. Due to its inaccessible and high altitude habitat, the brown bear has been poorly studied in India, as well as in other parts of the Asian highlands.In the recent decade, the widespread exponential growth of the human population, infrastructure development, and agricultural intensification has led to the alteration of natural habitats into human-modified landscapes, bringing humans and wildlife into close proximity. In areas where brown bear and human habitation are in close proximity, brown bears feed on agricultural/horticultural crops and livestock predation leads to human-brown bear conflict and lessens local tolerance for bears. As the human settlements encroach further into remote areas, bear-human conflict escalates. Himalayan brown bear in its distribution range in India facing prevailing threats such as habitat loss, cropland expansion, anthropogenic disturbances, human brown bear conflict and climate changes. The present study was proposed to understand in detail the habitat use and feeding habits of brown bear with respect to human-brown bear conflict to develop mitigation strategies. For conducting this study, the vast geographic area of Lahual valley was stratified into different habitats and then divided into 10 km × 10 km grids for extensive study. First objective of this study aimed to understand the habitat utilization pattern of the Himalayan brown bear in selected grids of Lahaul Valley across the seasons (Intensive study area). To achieve this objective sign survey and camera trapping data was used and sixty-five logistically possible grids were surveyed across the seasons (summer and pre-hibernation), in different habitats and elevation gradients.he findings of the present study highlight a distinct seasonal pattern in habitat use of the Himalayan brown bear. In summer, bears predominantly utilized the areas with extensive vegetation cover as evidenced by a positive association with rangeland and Shannon diversity index and NDVI-summer, particularly away from the human settlements in the elevation range of 3000m to 4500m. Conversely, in the per-hibernation phase, Himalayan brown bear tends to avoid high-altitude areas with limited vegetation, opting for areas with available vegetative materials. Notably, habitat use was concentrated in the elevation range of 2800m to 3800m closer to the human settlements in comparison to summer. Regardless of the season, the Himalayan brown bear utilizes areas near roads, emphasizing the availability of anthropogenic food resources.