To Breed or Not to Breed? An Examination of Reproductive Success of Translocated Eastern Quolls

Abstract

Conservation translocations are increasingly important for threatened species management. Translocations can achieve a range of positive conservation outcomes, such as recovering or expanding the range of a threatened species or increasing the size and genetic diversity of a population. The eastern quoll—a mesopredator extirpated from mainland Australia and declining across the island of Tasmania—is a species in need of conservation intervention, with captive to wild translocation at the forefront of current management techniques. However, efforts thus far have focused on reintroduction onto mainland Australia, rather than addressing the ongoing declines experienced by extant Tasmanian populations. To begin combatting declines of Tasmanian populations, a trial reinforcement of a wild eastern quoll population was conducted in November 2020 using 20 individuals from captive populations. This trial aimed to determine whether reinforcement could bolster population size and genetic diversity, reducing the likelihood of the population entering an extinction vortex. Following the reinforcement, we assessed the contribution of translocated adults to the subsequent cohort by genotyping both local and translocated adults, as well as juveniles born the following season. This allowed us to infer juvenile parentage and assess the contribution of translocated adults to the subsequent generation. We found that none of the genotyped juvenile cohort (n = 20) were conceived from translocated adults. Possible explanations include incomplete sampling of the juvenile cohort, age, naivety, intraspecific competition and increased rates of mortality or dispersal of translocated adults relative to the local population.