The Genetic Impact of isolation in Tiger populations (Essay Sample)

The Genetic Impact of isolation in Tiger Populations Student's Name Institutional Affiliation Professor's Name Due date The Genetic Impact of Isolation in Tiger Populations Introduction The loss of genetic diversity and reduced prime habitat are some of the most influential factors resulting in wildlife populations' extirpation and species extinction (Natesh et al., 2017). In the face of populations' isolations and habitat fragmentation, maintaining a population's genetic connectivity across these habitats is challenging, however critical in enhancing genetic variation and averting the negative consequences of inbreeding and genetic drift. Genetic variation across populations informs evolutionary history, species connectivity, and demographic variation over a certain period (Whiteley et al., 2015). Such information is essential in monitoring endangered species, where strategic conservation planning and management rely on precise data on the species status and structure, among others. Isolation, among other variables, affects the movement of gametes, individuals and groups in a natural population to influence the gene flow patterns, profoundly influencing the spatial and temporal distribution of the population's genetic variation and, consequently, their evolutionary progress. This paper focuses on the impact of isolation on the tiger population, establishing reasons why it needs genetic rescue. Isolation and Effects on Tiger Populations The tiger (Panthera tigris) species is an endangered species of global conservation concern (Natesh et al., 2015). In the past two decades, its population range has declined by about 90 per cent, with the species currently occupying about 7 per cent of its historic range. In contemporary days, the small remaining tiger populations are concentrated within Tiger Conservation Landscapes (TCLs), distributed across various tiger habitats (Armstrong et al., 2030). Apart from poaching, fragmentation and isolation remain the ultimate threat to extant tiger populations' survival and fitness. Generally, inbreeding in such small fragmented populations is inevitable, increasing a population's risk of extinction due to genetic stochastics of inbreeding (Whiteley et al., 2015). Inbreeding depression is considered the most immediate threat to a population's persistence. Thus, maintaining genetic connectivity for tigers is crucial in preserving genetic variation and long-term population fitness. Despite experiencing an extremely severe bottleneck in recent decades and the extinction of Javan, Bali, and, Caspian subspecies, tigers, especially the Bengal species, retain a higher than expected genetic diversity (Armstrong et al., 2015). A significant amount of this diversity is harboured in Indian habitats but with little genetic connectivity, where each tiger subspecies form a specific phylogenetic group (Natesh et al., 2017). The level of genetic diversity currently observed in contemporary tiger populations is a remnant of a much larger historical population that has not yet been influenced by genetic drift (Whiteley et al., 2015). Inbreeding, even among the Bengal subspecies with the highest diversity, has been observed (Armstrong et al., 2020), potentially decreasing genetic diversity. Low genetic diversity can negatively affect a species' fitness and, consequently, its survival (Frankham, 2015). Reduced genetic diversity is also associated with reduced male fertility in numerous species, which significantly compromise the population's demographic recovery, hence pushing the species further to extinction (Whiteley et al., 2015). Therefore, it is essential to increase the tiger population size before this observed genetic diversity is lost. Once lost, this genetic diversity's recovery will be impossible to achieve over millions of years, even with increased population sizes. In many small fragmented populations, the probability of extinction approximately ranges from 70-80 per cent (Frankham, 2015). This range is alarming as many tiger populations have been isolated for about 40 years (Armstrong et al., 2015). Most of the small TCLs populations are perhaps in the early stages of the inbreeding extinction threshold. This indicates that efforts to enhance connectivity between the small isolated populations are needed as they potentially minimize the risk of local extinction if they coincide with initiatives to increase the carrying capacity of the current tiger habitats (Whiteley et al., 2015). Enhancing gene flow between isolated populations can ameliorate the potentially detrimental effects of inbreeding influenced by isolation. Rescue Measures A significant way that can be used to rescue tigers is through the mating of different tiger subspecies. Mating different subspecies enhance gene flow, increases genetic diversity, and protects a population from the detrimental effects of genetic drift and inbreeding (Whiteley et al., 2015). This strategy has been effectively implemented in the genetic rescue of Florida panther (Puma concolor coryi) in the face of extinction (Frankham, 2015). Though increasing genetic diversity is the primary goal of mating different subspecies, it can be used to select specific inherited characteristics that confer an individual with high chances of survival (Natesh et al., 2015), given the contemporary dynamic and changing world. It is vital to prevent further habitat fragmentation of the large tiger populations to conserve the existing gene diversity. Habitat fragmentation results in population isolation, increasing chances of inbreeding and genetic drift (Natesh et al., 2017). Based on various simplifying assumptions, researchers consider that movement of one migrant per generation is sufficient to reduce the loss of a population's heterozygosity while also allowing genetic divergence among populations (Frankham, 2015). Thus, pre...