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. 2022 Jul 13;12(1):11913.
doi: 10.1038/s41598-022-14150-9.

Using PVA and captive breeding to balance trade-offs in the rescue of the island dibbler onto a new island ark

Zahra Aisya #  1 , Daniel J White #  2 , Rujiporn Thavornkanlapachai  3 , J Anthony Friend  4 , Kate Rick  1 , Nicola J Mitchell  1
Affiliations

Using PVA and captive breeding to balance trade-offs in the rescue of the island dibbler onto a new island ark

Zahra Aisya et al. Sci Rep. .

Abstract

In the face of the current global extinction crisis, it is critical we give conservation management strategies the best chance of success. Australia is not exempt from global trends with currently the world's greatest mammal extinction rate (~ 1 per 8 years). Many more are threatened including the dibbler (Parantechinus apicalis) whose remnant range has been restricted to Western Australia at just one mainland site and two small offshore islands-Whitlock Island (5 ha) and Boullanger Island (35 ha). Here, we used 14 microsatellite markers to quantify genetic variation in the remaining island populations from 2013 to 2018 and incorporated these data into population viability analysis (PVA) models, used to assess factors important to dibbler survival and to provide guidance for translocations. Remnant population genetic diversity was low (< 0.3), and populations were highly divergent from each other (pairwise FSTs 0.29-0.52). Comparison of empirical data to an earlier study is consistent with recent declines in genetic diversity and models projected increasing extinction risk and declining genetic variation in the next century. Optimal translocation scenarios recommend 80 founders for new dibbler populations-provided by captive breeding-and determined the proportion of founders from parental populations to maximise genetic diversity and minimise harvesting impact. The goal of our approach is long-term survival of genetically diverse, self-sustaining populations and our methods are transferable. We consider mixing island with mainland dibblers to reinforce genetic variation.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
(a) Current distribution of island dibblers in Jurien Bay and historic distribution of dibblers in Australia (inset). Dirk Hartog Island, the location of the new translocation, is also shown. (b) STRUCTURE analysis showing the number of genetic clusters (K = 2) within island dibblers and the level of admixture in the Escape Island population. Black lines separate islands and collection years. B Boullanger, W Whitlock, E Escape. Dibbler image sourced from Creazilla under an Attribution 4.0 International (CC BY 4.0) license. Image can be found at https://creazilla.com/nodes/64031-dibbler-clipart.
Figure 2
Figure 2
Changes in genetic diversity in island dibbler populations over time. (a) Expected heterozygosity, (b) individual heterozygosity, (c) allelic richness, (d) relatedness.
Figure 3
Figure 3
One hundred-year projections of survival probability, population size and gene diversity for the dibbler populations on Boullanger (solid line), Whitlock (large dashes), and Escape (small dashes) Islands.
See this image and copyright information in PMC

References

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