Phylogeography and population genetics of the Bengal Tiger (Panthera tigris tigris) in the Indian Subcontinent

Abstract

The tiger (Panthera tigris) typifies endangered large species across the globe. The Indian subcontinent currently harbours about 60% of the global tiger population (? 3200-3500) in an estimated 8-25% remaining tiger habitats. Little is known about the genetic makeup and diversity of historical and present tiger populations. As most of the residual populations are small and poorly interconnected, adequate understanding of patterns of genetic variation, population structure and dynamics will be critical for their survival. newlineThis dissertation addressed this gap in our knowledge of tiger biology by evaluating the genetic variation harboured by Indian tigers in the recent past and the present and developing tools that use genetic information to answer questions at various biological levels. newlineFaecal sample based genetic data reveal that Indian tigers retain more than half of the extant genetic diversity in the species. Coalescent analysis attributes this high diversity to a historically large population size in peninsular India that declined within last 200 years. Genetic data from geo-temporally referenced museum tiger samples reveal much higher number of historical mitochondrial DNA variants, the majority of which (93%) are currently extinct in modern populations. Further analyses indicate an increase in population differentiation among current tiger populations for both mtDNA and microsatellites, indicating a decrease in connectivity. newlineWe have developed rigorous field and laboratory-based protocols to assess distribution, abundance, individual identification, demographic ratio and genealogical relationships of tigers. Population estimation using faecal-DNA based individual identification in a mark-recapture framework at Bandipur national park closely matched abundance estimates generated from photographic capture-recapture sampling.