M Sc Dissertation(WII)

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Subject: search.filters.subject.Anthropogenic impact on wildlife

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    Golden Langur Distribution, Habitat Selection and Corridor – Connectivity: Assessing Patterns and Addressing Threats
    (Wildlife Institute of India, Dehradun, 2024) Basumatary, Rishi; Nath, Anukul; Gopi, G.V.; Chetry, Dilip
    The Golden Langur (Trachypithecus geei), is an endangered colobine primate, confined to fragmented forest patches in western Assam, India, and south-central Bhutan. The golden langur has experienced severe habitat loss and fragmentation due to ethnolinguistic and religious conflicts between the late 1980s and late 1990s, followed by developmental activities in western Assam. The primary threat faced by the golden langur in India are the rapid reduction of its natural environment and the fragmentation of its habitat. Factors such as a limited population size, the breakdown of meta-population dynamics, and unique traits of a species often make a population in a fragment more likely to experience local extinction. Due to the significant decline in the range of Golden langur in both Bhutan and India, as well as the ongoing destruction of their habitat in India, it is imperative to safeguard even the smallest local populations. The populations residing in these fragmented Reserved Forests and Proposed Reserved Forests are effectively confined, separated from the primary breeding population, and susceptible to demographic and genetic influences. The objective of this study is to understand the current distribution, suitable habitat, and connectivity of corridors for the severely fragmented southern population of golden langur in India. Additionally, the study aims to examine the specific habitat preferences and demographic patterns of langur groups, as well as evaluate the threats that this fragmented population faces. The study was carried out in nine fragmented forest patches that includes Wildlife Sanctuary (WLS), Community managed RF (CMRF) Reserved Forest (RFs), and Private Rubber Plantations and Adjoining Forests (PRP_AF). In the present study, a total of 123 trails, ranging from 0.4 km to 1.6 km, were walked, covering a total distance of 118.72 kilometers. During these surveys, a total 51 troops (including 8 multi-male multi-female troops and 5 all-male groups), consisting of 499 individuals were encountered. The mean group size and age-sex ratio between different protected regimes that include wildlife sanctuary (WLS), community managed RF (CMRF), reserved forest (RF) and private rubber plantation and adjoining forests (PRP_AF) were compared. The overall mean group size of the langur was 9.78 (± 0.69 SE). Of the total 499 individuals, 13.22 % comprised of adult males, 41.88 % adult females, 16.83 % sub-adults, 10.02 % was juveniles and 18.03 % was infant. The average age-sex ratio of adult males to adult females was 0.287 (± 0.04 SE), juveniles to adult females was 0.224 (± 0.02 SE) and infants to adult females was 0.407 (± 0.04 SE). The infant to female ratio was found higher in wildlife sanctuary as compared to other reserved forests in the study area. The current study revealed that approximately 883 km² of the area is highly suitable for the endangered golden langur. Percent forest cover was found to be the most important variable in determining the probability of occurrence of golden langur in India. The corridor connectivity analysis showed high conductance for corridors namely Bamungaon and Khoragaon RF. Similarly, the connectivity is permeable between Kakoijana and Bamungaon. Other corridors identified in the study are Bhumeshwar Hill, Nakati RF and Kakoijana RF. On the other hand, there is high conductance among corridors of Chakrashila WLS and Nadangiri RF. Additionally, fine scale habitat selection study showed that tree species diversity, canopy cover and food plant density are the key in determining the occurrence of golden langur. In the last six years, a total of 56 mortality and injury incidents were reported from the study area which include 45 deaths and 11 injuries. Electrocution accounted for 29 cases, especially near forest edges, while 21 road accidents occurred mainly on national and state highways, as these roads are broader and have higher traffic volumes compared to village and town roads. Most accidents happened in the corridors between Chakrashila WLS-Nadangiri RF and Kakoijona RF-Bamungaon RF. Specific measures need to be taken to minimize electrocutions and road accidents of golden langur in the region. Mitigation measures like insulating electric lines and road safety protocols such artificial canopy bridges (ACB) and metal animal overpasses (MAOP) are essential for safe and easy movement along these corridors for the golden langur's survival in fragmented habitats
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    Leveraging citizen science for bird monitoring: A case study assessing the impacts of urbanization on bird assemblages of the Nilgiris
    (Wildlife Institute of India, Dehradun, 2024) Phinehas N, David; Kher, Varun; Robin, V.V.; Jha, Ashish
    Anthropogenic alteration of habitats is the leading cause for biodiversity loss across the world. To accommodate the ever increasing human population, intensification of urbanised areas have led to the most extreme forms for habitat alteration (Batáry et al., 2018) and imposes a unique set of ecological filters. 2. Over that last 2 centuries during the colonial past, the Nilgiris has witnessed large-scale change in the landscape structure from native shola-grassland matrix to extensive tea and eucalyptus plantations. Currently it has emerged into a tourist haven, attracting millions every year, leading to expansion of the urban cover to accommodate the growing demand. 3. This study illuminates the profound effects of urbanization on bird communities in the Nilgiris, showcasing how habitat transformation alters community parameters such as, species richness, abundance, and composition. My results indicate a stark pattern: as urbanization intensifies, species richness declines, while a select few generalist species thrive in high abundance. 4. My findings reveal that settlements and proximity to remnant shola patches are the primary factors influencing avian community structure. Areas with higher settlement percentages and greater distances from shola patches exhibit reduced species richness and diversity. In contrast, less urbanized areas, closer to natural habitats, maintain higher biodiversity. This aligns with the hypothesis that urban environments simplify habitat structures, creating 'filter' that only a limited number of species can pass through, thereby fostering biotic homogenization. 5. Urban generalists, such as the House Sparrow, Rock Pigeon, and House Crow, flourish in highly urbanized zones due to their ability to exploit the abundant food resources and nesting sites provided by human activities. These species benefit from the homogenized urban landscape, which offers ample opportunities for foraging and nesting, often at the expense of more specialized species. Conversely, endemic shola forest specialists, such as the Nilgiri Laughing thrush and the Black-and-orange Flycatcher, suffer due to their stringent habitat requirements and limited dispersal abilities. These findings highlight the ecological trade-offs imposed by urbanization, where habitat degradation and loss disproportionately impact species with narrow niche widths. 6. This study also highlights the usefulness of citizen science as a tool for collection of largescale data in a short time span. I also tested for the accuracy of the citizen science data against a research-grade benchmark, ie, data collected by me. The results suggest that no significant variations were detected between the two datasets. 7. Conservation Implications: Monitoring species with vulnerable traits to keep track of further degradation of the habitat and involvement of the local citizens is needed. The study highlights a critical need to preserve remaining shola fragments and implementation of biodiversity friendly urban planning.
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    The serprntine devil: roads in the wood - a study on the impacts of a national highway on wildlife in Haridwar Forest Division
    (Wildlife Institute of India, Dehradun, 2017) Sultan; Pandav, Bivash; Habib, Bilal
    1. The ongoing and reckless development of linear infrastructure around the world can well be compared to sweet venom. Sweet for humans, venom for wildlife. Roads in particular, entail wide ranging impacts on wildlife. The most conspicuous of all is wildlife mortalities due to collision with vehicles. Of the indirect impacts i.e., barrier effects are the most widely acknowledged. For wild animals, these effects can lead to the development of avoidance behaviour (road avoidance, vehicle avoidance and traffic emission avoidance). Road densities around the world are expected to increase rapidly in the near future which will magnify the impact on natural habitats. It is therefore imperative to study the ill effects of roads, factors influencing them and suggest effective mitigations measures. 2. My study aimed to understand the impacts of a 30km stretch of National Highway 74 on wildlife in Haridwar Forest Division. The highway bisects the intensive study area (150 sq km.), cutting through three wildlife rich forest ranges of the Haridwar Forest Division. The highway carries a huge traffic volume and a high number of road-kills have been reported in the past. 3. The study was carried out with the following objectives: 1. to understand the extent of wildlife mortalities and the factors governing them ii. to understand ungulate habitat use and density distribution with respect to road iii. to suggest effective mitigation measures that can minimise the impact of NH- 74 on wildlife in the study area