Genetic Management of Captive and Reintroduced Bilby Populations

Abstract

Captive breeding and translocation, whereby selected individuals are used to supplement or re‐establish failing populations, are powerful tools for conserving threatened fauna. These tools, however, are rarely successful at establishing self‐sustaining populations that can survive without ongoing human assistance. The maintenance of genetic diversity and demographic security in captivity, or following wildlife translocation events, is important for improving the long‐term effectiveness of threatened species recovery efforts around the world. Routine population monitoring using hypervariable genetic markers represents a promising technique for evaluating the effect of established management practices on population structure and genetic diversity across various spatial and temporal scales. In this study, we employed a data set of 1,068 single nucleotide polymorphisms to conduct a comprehensive survey of population structure and genetic diversity in greater bilbies (Macrotis lagotis) held at 13 zoos and wildlife sanctuaries across Australia between August 1996 and December 2016. We observed significant genetic structuring across the study sites, consistent with the limited exchange of animals between independently managed facilities. The majority of variation, however, still occurred at the level of individual bilbies (75%, P < 0.001). We also uncovered evidence for an ongoing loss of genetic diversity in some conservation‐fenced populations, despite a slight excess of heterozygosity across the sampling sites as a whole. Maintaining the genetic health of bilbies in captivity or following translocation will therefore require stakeholders to focus on reducing individual mortality, and maintaining genetic connectivity across all existing populations through the regular exchange of selected individuals. As such, admixture is expected to play an increasingly important role in future conservation programs. © 2019 The Authors. Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Genetic effects of long-term captive breeding on the endangered pygmy hog

“…Genetic management of captive populations has gained importance over the last few decades and supplementing captive populations with wild individuals has been a recurrent management theme for highly endangered species (Ballou et al, 2010;Lott et al, 2020), with the genetic benefits of such an action being (1) Increasing the genetic diversity of the wild population and (2) Reducing the genetic differentiation between the wild and captive populations. On the contrary, a mandate to increase genetic diversity in captive populations may also lead to outbreeding depression if the founders belonged to genetically differentiated populations.…”

Monitoring the Abundance of Wild and Reintroduced Bilby Populations

“…Reintroducing bilbies into fenced predator‐free areas has become a popular strategy (Moseby and O'Donnell 2003, Helmstedt et al 2014, Anson 2017), but it creates inherent problems in the future because these populations experience genetic bottlenecks (Miller et al 2015, Lott et al 2020). This strategy also requires additional management burdens of exchanging animals, harvesting from wild populations, managing overstocking with supplemental feeding, and removing stock or culling when fenced areas become overpopulated.…”

Future‐proofing the koala: Synergising genomic and environmental data for effective species management

“…Variant sites with call rates of <90% and minor allele frequencies of <0.006 were removed from the data set. This MAF threshold was selected to minimise the likelihood of including false alleles due to sequencing error by ensuring that each allele was sampled in ≥2 individuals independently (as demonstrated by the formula 3/2 N: 3/(2 × 259) = 0.006) (Lott et al, 2020; Wright et al, 2019).…”