Translocations and their effect on population genetics in an endangered and cryptic songbird, the Noisy Scrub-bird Atrichornis clamosus

ABSTRACT

Best practice for conservation translocations dictates that large founder cohorts be used, in part to ensure that the maximum genetic variation from the source population is captured. Population bottlenecks caused by low founder numbers are understood to typically have a detrimental effect on genetic diversity and promote inbreeding. However, for some species, translocating large numbers of individuals may require an unfeasible allocation of resources or have a harmful effect on the source. The Noisy Scrub-bird (Atrichornis clamosus) is a cryptic and rarely observed passerine that was once believed extinct, and translocations to successfully establish new populations have been instrumental in securing its future. However, due to the inherent difficulties in capturing this elusive bird, these populations have been founded from only 11 to 31 individuals. We used 10 microsatellite markers to compare the genetics of the original source to the two extant translocated populations. Allelic diversity and heterozygosity were generally low but highest in the source population. Although translocations seem not to have conferred significant additional losses, relatedness, inbreeding and mean kinship were highest in the population founded with just 11 individuals. Despite historical evidence to the contrary, we found a bottleneck signature in just one population. The two translocated populations displayed significant differentiation from each other and there was evidence of spatial genetic structure between these populations. Additionally, there was some evidence of cryptic subdivision (Wahlund Effect). In light of these findings, we make recommendations for future management actions to help retain what genetic diversity remains.

KEYWORDS:

• Translocations
• genetic diversity
• inbreeding
• cryptic species
• bottlenecks

Acknowledgements

Samples for this study were collected under permit from the WA Department of Biodiversity, Conservation and Attractions (DBCA) (and previous agency designations) and under consecutive DBCA Animal Ethics Committee approvals, with the most recent sampling taking place under approval number 35/2008. We would like to thank the South Coast Threatened Birds Recovery Team and Richard Allcock and Nina Kresoje at the Lotterywest State Biomedical Facility Genomics. Birdlife Australia provided significant support through the Stuart Leslie and Professor Allan Keast Bird Research Awards and funding for capture work was provided by South Coast NRM. The Guild of Mercers’ Scholars Charitable Trust also contributed towards field equipment. We would also like to thank the many DBCA staff (in particular Alan Danks and the late Peter Collins) and volunteers for their invaluable field assistance. We would like to thank two anonymous reviewers and the guest editor for their constructive input on this study and Helen Taylor who also provided feedback on an earlier draft of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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