No abstract

Conservation translocations can restore populations and prevent extinction of threatened species. Sourcing adequate genetic diversity is an essential consideration when planning reintroductions, because it influences individual fitness and long-term persistence of populations, yet available populations of threatened species may lack diversity. We estimated population genetic parameters for one of Australia’s most threatened mammals, the northern bettong, Bettongia tropica, to select source populations for reintroduction. Individuals from sites across the species’ extant range in the Wet Tropics of north Queensland were genotyped, using 6,133 informative SNPs. We found that samples clustered into four populations: an isolated northern population at Mt Spurgeon and three connected southern populations in the Lamb Range. Most of the species’ genetic diversity was dispersed across the Lamb Range populations in approximately equal proportions. Individuals showed an isolation-by-distance effect, even over short distances within continuous habitat. Admixture of populations was high at distances < 7 km but low at distances > 11 km, and there was asymmetrical gene flow between the two closest neighboring populations. All populations had small effective sizes and experienced drift, but connectivity appears to have mitigated drift and stabilized population sizes within the Lamb Range. The Mt Spurgeon population had a very small effective population size and low genetic diversity. We use our findings to weigh up the risks and benefits of mixing sources for reintroduction, and we recommend a mixed source approach. We do not currently recommend sourcing individuals from Mt Spurgeon and conservation efforts to preserve this population are urgently required.

Conservation translocations can restore populations and prevent extinction of threatened species. Sourcing adequate genetic diversity is an essential consideration when planning reintroductions, because it influences individual fitness and long-term persistence of populations, yet available populations of threatened species may lack diversity. We estimated population genetic parameters for one of Australia’s most threatened mammals, the northern bettong, Bettongia tropica, to select source populations for reintroduction. Individuals from sites across the species’ extant range in the Wet Tropics of north Queensland were genotyped, using 6,133 informative SNPs. We found that samples clustered into four populations: an isolated northern population at Mt Spurgeon and three connected southern populations in the Lamb Range. Most of the species’ genetic diversity was dispersed across the Lamb Range populations in approximately equal proportions. Populations showed an isolation-by-distance effect, even over short distances within continuous habitat. Admixture of populations was high at distances < 7 km but low at distances > 11 km, and there was asymmetrical gene flow between the two closest neighboring populations. All populations had small effective sizes and experienced drift, but connectivity appears to have mitigated drift and stabilized population sizes within the Lamb Range. The Mt Spurgeon population had a very small effective population size and low genetic diversity. We use our findings to weigh up the risks and benefits of mixing sources for reintroduction, and we recommend a mixed source approach. We do not currently recommend sourcing individuals from Mt Spurgeon and conservation efforts to preserve this population are urgently required.

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The 2019/20 wildfire season was devastating for Australia’s biodiversity and unprecedented in its extent and severity, yet the consequences for sites important for biodiversity and other world heritage values remain unknown. Here, we summarise the 2019/20 wildfire impacts on key sites set aside for, or identified as being important for, biodiversity, with specific reference to nationally designated protected areas, World Heritage Listings, and Key Biodiversity Areas (KBAs). We also explore patterns between burn extent or severity, and underlying landscape characteristics. Over seven months, approximately 10 million hectares (ha) of native vegetation burned. Of these burned landscapes, ~3.2 million ha (41%) were within the Australian protected area estate (n = 815 and impacted &gt;0.1% of each protected area). Six Australian World Heritage Listings were impacted by the 2019/20 wildfires, with the largest impact being in the Greater Blue Mountains World Heritage Area (680,000 ha or 67% was affected by the fires). The 2019/20 fires impacted over 2 million ha across 69 KBAs. Of these, 18 KBAs had &gt;15% of their area burned. Critically, for the management of intact and recovering forests, we show that the degree of forest integrity and ecosystem intactness affected fire severity: more degraded forests and ecosystems experienced higher severity burns in the protected area estate and KBAs. Recovery for many of these places will require targeted effort and resources to help reduce the likelihood of future megafires, as well as increased resilience in the face of other catastrophic environmental events.