Author ORCID Identifier
Biosketch
Abhinav Tyagi is a molecular ecologist with a research focus on understanding wildlife dynamics and addressing conservation challenges using genomic tools. He holds a Master’s degree in Biodiversity and Conservation and earned his Ph.D. in Connectivity and Conservation Genomics from the National Centre for Biological Sciences, Bangalore, and SASTRA Deemed University, Thanjavur, India. His doctoral research examined multispecies connectivity and how different species respond to habitat fragmentation in human-dominated landscapes. His expertise spans conservation genomics, wildlife connectivity, diet analysis using DNA metabarcoding, hybridization, epigenetics, and human–wildlife interactions. He has been awarded the prestigious David H. Smith Conservation Research Fellowship and is currently a postdoctoral researcher at Purdue University, Indiana, US, where he focuses on population genomics of North American river otters using modern and historical samples, as well as developing epigenetic clocks to age fish from otter diets to inform human–otter coexistence strategies. Dr. Tyagi is passionate about applying science to conservation practice, capacity building, and interdisciplinary collaboration.
Date of Award
7-5-2024
Document Type
Thesis
School
School of Chemical & Biotechnology
Programme
Ph.D.-Doctoral of Philosophy
First Advisor
Prof. Uma Ramakrishnan
Second Advisor
Dr. B Chandra Mohan Ramisetty
Keywords
ddRAD, Multi Species Connectivity, Wildlife Genomics, Non-Invasive Samples, Large Herbivores And Carnivores
Abstract
Many mammalian species, facing severe historic range reductions, now inhabit fragmented habitats. Habitat fragmentation involves the reduction of habitat into smaller patches, increasing distances between them, and eventually leading to small isolated populations. Species' responses to habitat alteration may vary based on factors such as body size, dispersal ability, and abundance. Understanding these differences is crucial for effective multispecies conservation planning. Genomic data, within a landscape genetic framework, are increasingly applied to evaluate the effects of habitat fragmentation and understand influential landscape features for connectivity. The quantity of data enhances the power and precision of assessing landscape impacts on gene flow. Recent advances in next-generation sequencing (NGS) make harnessing genomic data increasingly viable, extending its application to non-model wild species through non-invasive sampling methods. However, non-invasive samples pose challenges related to DNA quality and quantity, which is often compromised.
In this study, I developed methods enabling the use of fecal DNA to generate genome-wide data for endangered species. Using the Jungle cat as a model system, we attempted and achieved substantial enhancement in the proportion of host DNA. We demonstrate that using a higher number of markers provides more power than using a high number of individuals. Using the same standardized enrichment method, I attempted to understand the genetic connectivity of two large herbivores, gaur and sambar, to comprehend how different species, even with similar habitat associations, respond to various landscape features. We found that both gaur and sambar exhibit population structure in central India and are negatively impacted by roads and land-use changes. We also observed species-specific responses to various landscape variables, highlighting small and isolated populations for both species that require conservation intervention. In the process, we developed a double-digest restriction-associated DNA sequencing (ddRAD) protocol to suit low input host DNA concentration in generating empirical genomic data. Finally, I applied these methods to elucidate fine-scale multispecies connectivity for eight different species (Gaur, Sambar, Muntjac, Jungle cat, Dhole, Tiger, Leopard, and Sloth bear) and examined how different species, based on their body size, trophic level, social structure, abundance, and dispersal distance, are impacted by habitat fragmentation. We found no general pattern of resistance based on body size. However, landscape features offer higher resistance to herbivore movement compared to carnivores, and social species are more impacted by various landscape features compared to solitary species.
This study represents the first attempt where non-invasive samples were used to generate genome-wide data for several endangered species, investigating multi-species patterns of connectivity in a human-dominated landscape. The enrichment method applied to a range of endangered species is able to elucidate adequate genome-wide data for investigating fine-scale patterns of connectivity. Furthermore, multi-species patterns reveal that while some landscape elements affect all species, others appear to be species-specific. Incorporating such knowledge into conservation planning could potentially reduce local extinction risks and, more broadly, slow down ongoing biodiversity loss.
Recommended Citation
Tyagi, Abhinav Mr, "Fecal Genomics Provides Insights On Connectivity Of Endangered Wildlife In A Human Dominated Landscape" (2024). Theses and Dissertations. 4.
https://knowledgeconnect.sastra.edu/theses/4
Graphical Abstract