A multi-locus approach to discern conservation units and adaptive potential of Pacific Black Ducks across Australia and surrounding islands

ABSTRACT

Genetic diversity, population delineation and rates of gene flow can be used to help understand long-term population dynamics, which is important for conserving species with fragmented distributions. Here, we sequenced 19 nuclear introns (nuDNA) and a portion of mitochondrial DNA (mtDNA) across three subspecies of Pacific Black Ducks (Anas superciliosa ssp.; N_mtDNA = 162; N_nuDNA = 49) from Australia and surrounding islands in order to measure levels of genetic structure and gene flow. First, despite evidence of gene flow from Australia, Pacific Black Ducks from the Solomon Islands were significantly differentiated from all other groups in both mtDNA and nuDNA. This is probably due to genetic drift resulting in lowered genetic diversity. We found the lowest levels of genetic differentiation between locations sampled in Australia, suggesting strong connectivity across the continent. Despite elevated differentiation in mtDNA between Australia and other islands (i.e. Timor, New Zealand), low nuDNA divergence suggests some connectivity. Such marker discord is common among waterfowl and is likely due to male-biased dispersal from Australia. Finally, mtDNA of Pacific Black Ducks from New Zealand showed introgression of haplotypes from feral mallards (A. platyrhynchos), which were established in the 1800s. Overall, these data suggest that A. superciliosa ssp. consist of three distinct genetic units that correspond with subspecies classifications and require individual conservation planning.

KEYWORDS:

• Waterfowl
• population genetics
• conservation
• population structure

Acknowledgements

Sample collection was supported by an Australian Research Council Research grant LP0775076 to David Roshier and Leo Joseph. Funding for the genetic analyses was provided through a Research Initiation Grant at Wright State University. Research was carried out under permit WISP0452460 from the Queensland Environmental Protection Agency. We also thank Graham Burgess for providing samples and Alex Drew and Ian Mason for help with PNG field work. We are also grateful to: the late Barnabas Wilmott of the Papua New Guinea Conservation and Environment Protection Authority; staff at the National Research Institute, Port Moresby, PNG, for assistance before and during all field work; and Tonda Wildlife Management Committee for generously allowing us to undertake our research in the Bensbach region. We are grateful to the following people for help with PNG field work: Bob Bates, Hinterland Airlines, Kapai Assi and Garry Barmby; Biatus Bito and Miriam Supuma; Port Moresby staff of TNT; Mark Nizette; Jack Dumbacher, and the former Director, Andrew Moutu, and Bulisa Iova at the PNG National Museum and Art Gallery. We are especially grateful to the communities at Agevairu, Bensbach, Popondetta and Rigo for their support of field work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here.