Effects of insularity on genetic diversity within and among natural populations

Abstract

An insular environment or "island" is any area of habitat suitable for a specific ecosystem that is surrounded by an expanse of unsuitable habitat.Examples of insular systems include mountain tops, lakes, seamounts, enclosed seas, and isolated islands or reefs. These systems have several important properties that set them apart from non-insular systems and thus dictate their specific consideration in this assessment. … Many of these problems facing insular taxa are compounded when the insular habitats are very small and isolated, including tiny remote Pacific islands, alpine lakes, and desert oases. … Finally, the small population sizes typical of species living in small insular habitats can lead to genetic drift and inbreeding that greatly reduce genetic variation in some situations. As insular taxa are often very local, rare,

Population genetics and phylogeographic history of the insular lizardPodarcis lilfordi(Gunther, 1874) from the Balearic Islands based on genome-wide polymorphic data

“…A fundamental goal in population ecology and evolution is to understand the processes that maintain genetic diversity, and those that drive intraspecific/interpopulation divergence across geographic space and time (Avise, 2000). In small insular populations, free of predators and with no immigrants, genetic diversity is primarily driven by genetic drift (due to environmental and demographic stochasticity, both particularly important in tiny islets) and density-dependent selection due to competition for the limited local resources (Hoffmann et al, 2021; Hunt et al, 2022; Travis et al, 2023). Founder effect and high inbreeding levels are also expected to further reduce the population genetic variance and accelerate the process of divergence from the original source population (Keller and Waller, 2002).…”

Population genetics and phylogeographic history of the insular lizard Podarcis lilfordi (Gunther, 1874) from the Balearic Islands based on genome‐wide polymorphic data

“…A fundamental goal in population ecology and evolution is to understand the processes that maintain genetic diversity, and those that drive intraspecific/interpopulation divergence across geographic space and time (Avise, 2000). In small insular populations, free of predators and with no immigrants, genetic diversity is primarily driven by genetic drift (due to environmental and demographic stochasticity, both particularly important in tiny islets) and density‐dependent selection due to competition for the limited local resources (Hoffmann et al., 2021; Hunt et al., 2022; Travis et al., 2023). Founder effect and high inbreeding levels are also expected to further reduce the population genetic variance and accelerate the process of divergence from the original source population (Keller & Waller, 2002).…”

Differences in Albizia odoratissima genetic diversity between Hainan Island and mainland populations in China

“…This study revealed that the genetic abundance and complexity of the A. odoratissima population in Hainan were lower than those of the Baise population. This phenomenon that the genetic diversity of island population was lower than that of land population also exists in some species such as Mussaenda kwangtungensis (Guangdong) (Hufford et al, 2014;Shi et al, 2020;Hunt et al, 2022). Long-term geographic isolation is probably the main reason explaining the lower genetic diversity of the Hainan population.…”