Skewed paternity impacts genetic diversity in a small reintroduced population of western quolls (Dasyurus geoffroii)

Reintroduction programs can face issues maintaining genetic diversity due to founder effects, and subsequent bottlenecks related to mortality and reproductive skews in the first generations after release. We assessed genetic diversity and undertook a pedigree analysis of 12 founders and 23 first-generation western quolls (Dasyurus geoffroii) at a reintroduced population at Arid Recovery, South Australia, in 2018. Genetic pedigrees showed that five of the eight females and three of the four males produced offspring. We also identified multiple paternity in this species. However, skewed paternity was evident with one male siring 65% of the sampled offspring. The reason for the paternity skew is unclear. The most successful male was smaller in body mass but had the largest home range compared to the other males, was released 4 days prior to two of the other males and spent more time inside the reserve. Failure of 33% of founders to breed in the first year combined with the strong paternity skew indicate that genetic drift and inbreeding pose a risk to the long-term success of this reintroduction. Genetic management, including the release of additional males, has already been undertaken, but may be required longer-term. Future quoll reintroductions should test if releasing all males simultaneously reduces paternity skew, and paternity should be measured through several generations to determine if paternity skew is a reintroduction protocol issue or one that is common in small populations more generally.