Long-term genetic consequences of mammal reintroductions into Arid Recovery

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RESEARCH AREA
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This week’s featured research article has just been published in Biological Conservation by University of Adelaide researchers and examines the long-term genetic consequences of mammal reintroductions into the Arid Recovery Reserve, South Australia. Reintroduction programs aim to restore self-sustaining populations of threatened species to their historic range. However, demographic restoration may not reflect genetic restoration, which is necessary for the long-term persistence of populations. Four threatened Australian mammals, the greater stick-nest rat (Leporillus conditor), greater bilby (Macrotis lagotis), burrowing bettong (Bettongia lesueur) and western barred bandicoot (Perameles bougainville), were reintroduced at Arid Recovery Reserve in northern South Australia over the last 18 years. These reintroductions have been deemed successful based on population growth and persistence, however the genetic consequences of the reintroductions are not known. The researchers generated large single nucleotide polymorphism (SNP) datasets for each species currently at Arid Recovery and compared them to samples collected from founders. They found that average genetic diversity in all populations at the Arid Recovery Reserve are close to, or exceeding, the levels measured in the founders. Increased genetic diversity in two species was achieved by admixing slightly diverged and inbred source populations. The results suggest that genetic diversity in translocated populations can be improved or maintained over relatively long time frames, even in small conservation reserves, and highlight the power of admixture as a tool for conservation management. The researchers suggest that additional translocations to Arid Recovery may be unnecessary at this time, and highlight the clear benefit to reintroduction programs of admixing slightly diverged populations to maximise genetic diversity and adaptive potential in threatened taxa. Comparison of the two admixture strategies employed in the bettong and WBB populations at Arid Recovery show future translocation programs that plan to mix different genetic stocks should aim to release equal numbers of animals from both sources simultaneously, early in the reintroduction program. This will promote balanced admixture of both sources in the descendant population. The researchers conclude that they have demonstrated the benefits of genetic monitoring in reintroduction programs and advocate for its continued use at Arid Recovery and in other reintroduction programs in the future. The article can be downloaded here (or email jennie.fluin@sa.gov.au for a copy).