M Sc Dissertation(WII)

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Start date: 2020Subject: search.filters.subject.Human impact

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    Heat Hardening and the Influence of Thermal Heterogeneity of Habitat on Aboveground Activity in Spiny-tailed Lizard (Saara hardwickii)
    (Wildlife Institute of India, Dehradun, 2025) Vassa, Chirag Nimish; Dutta, Sutirtha; Kher, Varun
    Human induced climate change has challenged the persistence of many organisms at different biotic levels and alter their interaction with the environment. Ectotherms are particularly vulnerable to anthropogenic climate change due to their reliance on external environment for various life history traits. Thermoregulatory behaviour is often used by many ectotherms especially reptiles to regulate their body temperature and will be crucial in imminent future with intensification of climate change. Although behavioural thermoregulation is widely studied, but studies looking at influence of thermal heterogeneity of a habitat on aboveground activity is limited. Moreover, with escalation in global warming ectotherms might have to rely on another mechanism in addition to thermoregulatory behaviour to combat the effect. One such physiological mechanism is heat hardening a quick response to thermal tolerance that temporarily enhances thermal tolerance, allowing lizards to withstand greater temperatures for a short period. Despite its importance very limited data is available for heat hardening capacity in reptiles. This study examined the influence of thermal heterogeneity of a habitat on aboveground activity in spiny-tailed lizard (Saara hardwickii) and assessed their heat hardening capacity. Additionally, trade-off hypothesis was also tested which has been recently proposed to explain the dynamics of thermal tolerance plasticity. I found positive influence of habitat heterogeneity on aboveground activity of the lizard. However, individuals in both the conditions spent similar amount of time in different behaviours. With respect to phenotypic plasticity i.e. heat hardening, I did not find any evidence of thermal tolerance plasticity during my experimental trials but few individuals did show increased thermal tolerance implying intraspecific variation. Additionally, the results from heat hardening experiments found no support for trade-off hypothesis. My study underscores the importance of habitat heterogeneity for species like spiny-tailed lizard which thrives in extreme temperatures. Furthermore, Lack of phenotypic plasticity in thermal tolerance increases it’s risks to overheating and dependency on behavioural thermoregulation.
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    Spatial and Temporal Overlap of Nilgai (Boselaphus tragocamelus) and Cattle (Bos taurus) and Its Implications for Parasite Burden and Prevalence
    (Wildlife Institute of India, Dehradun, 2025) Singh, Surya Pratap; Kawlni, Lallianpui; Kolipakam, Vishnupriya; Sadhu, Ayan
    Humans have depended on domesticated animals and plants since the origin of agriculture, and forests and grasslands have provided essential resources such as grazing and forest products. But there is greater overlap today between livestock and wildlife as a result of greater deforestation and growing human activity, and this has implications for the transmission of disease at these interfaces. In this dissertation, the impacts of spatial overlap, environmental variables, and animal behavior are investigated for their influence on patterns and drivers of gastrointestinal parasite load in nilgai (Boselaphus tragocamelus) and cattle, a commensal wild ungulate of the Indian peninsula. During December 2024 to March 2025, the study was conducted in the Darra enclosure of Mukundra Hill National Park. In addition to spatial information regarding animal locations with respect to villages, water points, and livestock distribution, field measurements were collected on parasitic burden, which was expressed as eggs per gram (EPG) in fecal samples. The research attempted to determine the impacts of spatial overlap among livestock and wildlife and proximity to these attributes on parasite intensity and prevalence. Statistical tests revealed no substantial relationship between the parasitic load of cattle and their proximity to villages or water points, contrary to preliminary hypotheses. All individuals sampled carried high EPG values consistently, revealing an overall parasite burden. Widespread parasite exposure regardless of spatial gradients due to common grazing, minimal pasture rotation, and homogenous environmental conditions are most likely the primary reasons for such a pattern. The research explored whether temporal and spatial coincidences with livestock, in this case cattle, can be channels of parasite transmission for nilgai. The findings indicate that the impact of spatial proximity can be overcome by aggregating at shared resources and chronic exposure to soiled environments and that it consistently yields high infection rates in domestic and wild ungulates. These results underscore the importance of considering environmental context, grazing management, and animal behavior when designing parasite control strategies. Instead of simply considering physical distance to villages or water sources, interventions taking into account pasture management and resource allocation may be more effective. The research presents valuable information for the prevention of disease, management of wildlife, and conservation of India's domestic and wild ungulates.