Genetic mixing in conservation translocations increases diversity of a keystone threatened species, Bettongia lesueur

Heidi M Nistelberger; Emily Roycroft; Anna J Macdonald; Shelley McArthur; Lauren C White; Patrick G S Grady; Jennifer Pierson; Colleen Sims; Saul Cowen; Katherine Moseby; Katherine Tuft; Craig Moritz; Mark D B Eldridge; Margaret Byrne; Kym Ottewell

doi:10.1111/mec.17119

Genetic mixing in conservation translocations increases diversity of a keystone threatened species, Bettongia lesueur

Mol Ecol. 2023 Sep 16. doi: 10.1111/mec.17119. Online ahead of print.

Authors

Affiliations

¹ Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia.
² Division of Ecology & Evolution, Research School of Biology, ANU College of Science, The Australian National University, Canberra, Australian Capital Territory, Australia.
³ Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia.
⁴ Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA.
⁵ Australian Wildlife Conservancy, Subiaco, Western Australia, Australia.
⁶ Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
⁷ Arid Recovery, Roxby Downs, South Australia, Australia.
⁸ Terrestrial Vertebrates, Australian Museum Research Institute, Sydney, New South Wales, Australia.

PMID: 37715549
DOI: 10.1111/mec.17119

Abstract

Translocation programmes are increasingly being informed by genetic data to monitor and enhance conservation outcomes for both natural and established populations. These data provide a window into contemporary patterns of genetic diversity, structure and relatedness that can guide managers in how to best source animals for their translocation programmes. The inclusion of historical samples, where possible, strengthens monitoring by allowing assessment of changes in genetic diversity over time and by providing a benchmark for future improvements in diversity via management practices. Here, we used reduced representation sequencing (ddRADseq) data to report on the current genetic health of three remnant and seven translocated boodie (Bettongia lesueur) populations, now extinct on the Australian mainland. In addition, we used exon capture data from seven historical mainland specimens and a subset of contemporary samples to compare pre-decline and current diversity. Both data sets showed the significant impact of population founder source (whether multiple or single) on the genetic diversity of translocated populations. Populations founded by animals from multiple sources showed significantly higher genetic diversity than the natural remnant and single-source translocation populations, and we show that by mixing the most divergent populations, exon capture heterozygosity was restored to levels close to that observed in pre-decline mainland samples. Relatedness estimates were surprisingly low across all contemporary populations and there was limited evidence of inbreeding. Our results show that a strategy of genetic mixing has led to successful conservation outcomes for the species in terms of increasing genetic diversity and provides strong rationale for mixing as a management strategy.

Keywords: Barrow Island; Shark Bay Islands; burrowing bettong; conservation; ddRADseq; historical DNA; target capture; translocation.