Problems of reduced genetic diversity
Populations with reduced genetic diversity face an increased risk of extinction. Without genetic variation, a population cannot evolve in response to changing environmental conditions.
Genetic diversity generally underpins population resilience and persistence. Reductions in population size and an absence of gene flow can lead to reductions in genetic diversity, reproductive fitness, and a limited ability to adapt to environmental change increasing the risk of extinction.
This occurs during population bottlenecks or in very small populations such as those on islands. Island populations are typically small and isolated, and as a result, inbreeding and reduced genetic diversity elevate their extinction risk.
Two island populations of the platypus exist; a naturally occurring population on King Island in Bass Strait and a recently introduced population on Kangaroo Island off the coast of South Australia. Research has shown that levels of genetic diversity in King Island platypuses are perilously low. The small population size and the limited founders combined with genetic isolation are likely to lead to further losses of genetic diversity through time for the Kangaroo Island platypus population.
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