Gaps in genetic knowledge affect conservation management of kiwi (Apteryx) species

Abstract

Worldwide, there is growing appreciation of the importance of integrating genetic information into conservation management. However, there are commonly occurring problems which impact on doing this successfully. This issue is well illustrated by kiwi Apteryx species. Like many endangered taxa, extant kiwi populations are small, fragmented and isolated, raising concerns of potential inbreeding depression. Accordingly, kiwi conservation includes discussion of genetic management and translocations. To date, kiwi taxa have been the subject of 41 genetic studies. Here we provide the first synthesized review of these studies. We conclude that despite the impressive study effort, current understanding of kiwi genetics is insufficient to guide genetic management, predict translocation outcomes and manage biological diversity to achieve future sustainability of the species. We explain why, and outline research questions that can be addressed with new genome science technologies. Using new technologies to build on the foundation of work already undertaken, we see a great opportunity to address key issues for North Island Brown Kiwi Apteryx mantelli that are central to the conservation concerns for many threatened species. Specifically, we suggest that historical, disjunct, mainland populations combined with translocations of North Island Brown Kiwi to offshore islands have generated unique case studies to investigate the effects of fragmentation, cessation of gene flow, inbreeding, outbreeding and hybridization on biological diversity.

Predicting breeding systems to guide conservation strategies: A kiwi example

“…The potentially extensive impact of breeding systems and their variability highlights the need to incorporate breeding biology into the already challenging field of predicting translocation outcomes (Undin, Hills, Lockhart, & Castro, 2021a; Undin, Lockhart, Hills, & Castro, 2021b). As described above, resource distribution is one of the main factors determining breeding systems, and breeding systems as well as mating strategies can change with population density, habitat, and/or availability of territories and mates (Carrete et al, 2006; Griffith et al, 2010; Heinsohn et al, 2019; Pribil & Searcy, 2001; Walker et al, 2008).…”

“…In addition, these activity registering transmitters have greatly increased the potential for studying kiwi ecology, incubation behavior, and breeding success rate (e.g., Bansal, 2020; Cunningham & Castro, 2011; Dixon, 2015; Hiscox, 2014; Wilson, 2014; Ziesemann et al, 2011). This progress is important as many questions remain unanswered, not the least regarding how to optimize kiwi translocations and further incorporate behavior in conservation management (Jahn et al, 2022; Undin, Hills, Lockhart, & Castro, 2021a; Undin, Lockhart, Hills, & Castro, 2021b).…”

“…(3) Directly linked to the latter, the prevalence of polygamy may compensate for a small founder population size. Among other things, this compensation means that the current strict cut off at a founder size of 40 individuals to consider a historic translocation successful (Germano et al, 2018; Jahn et al, 2022) may need to be re‐evaluated (Undin, Hills, Lockhart, & Castro, 2021a; Undin, Lockhart, Hills, Armstrong, & Castro, 2021c; Undin, Lockhart, Hills, & Castro, 2021b). (4) The higher the prevalence of polygamy, the harder it will be to assume relatedness between individuals based solely on the identity of the incubating male (cf.…”

Mixed Mating in a Multi-Origin Population Suggests High Potential for Genetic Rescue in North Island Brown Kiwi, Apteryx mantelli

“…A first step would be to further examine the genetic dissimilarity between partners and investigate if it is predominantly linked to and/or exaggerated in certain regions of the genome (Beaumont and Balding, 2004;Fitzpatrick et al, 2010;Keller et al, 2013). Such studies would not only increase our understanding of Apteryx breeding but also take us closer to understanding the significance and nature of the genetic differences observed between Apteryx taxa today (see Undin et al, 2021a).…”

“…The study by Weir et al (2016) found a Pairwise Hudson's F st of 0.139 (95% CI 0.120-0.158) between the Northland and Western taxa, and dated the split between these management units, and thus between the parental populations of Ponui Island, to between 100,000 and 220,000 years ago. Whilst local adaptations might have evolved over this period of temporal divergence, the extent and nature of any local adaptation remains unknown (Undin et al, 2021a).…”