Survival and establishment of the brush-tailed bettong (Bettongia penicillata ogilbyii) translocated into a predator suppressed landscape

The success of wildlife translocations depends on a variety of intrinsic and extrinsic factors, including the geographical and genetic origin of the founding individuals, the demographic and morphometric profile of the individuals, as well as the timing and method of release. Improving our mechanistic understanding of how such factors influence post-translocation establishment informs future releases and increases the probability of success. This study documents the first successful landscape-scale reintroduction of brush-tailed bettongs ( Bettongia penicillata ogilbyi ) on mainland Australia, where introduced mammal predators (red fox, Vulpes vulpes and feral cat , Felis catus) have not been excluded . Here we describe the establishment and breeding of 193 individuals from five source populations translocated into Dhilba Guuranda-Innes National Park, South Australia over 22 months. Morphological analyses revealed that bettongs from predator-exposed founder populations had larger pes lengths and greater body weights than those from predator-naïve populations, indicative of potential adaptive benefits for predator evasion and resource competition. Apparent survival estimates increased with time since translocation and were initially higher in release cohorts from populations that had both morphologically larger individuals and previous predator exposure. Individuals that were supplemented into the population had comparatively lower initial survival estimates, despite having the same traits that had been found to increase initial reintroduction survival. More than half of the estimated ~400 individuals in the population were locally born. These findings underscore the impacts of source population traits and release conditions in translocation outcomes, offering valuable insights for future conservation and rewilding studies in open, unfenced landscapes. • Wild breeding population of bettongs successfully established in South Australia • Successful reintroduction of bettongs alongside feral cats and foxes • High representation of bettongs born following translocation in wild population • High survival linked to previous predator exposure and morphologically larger bettong founders • Supplementary releases have lower survival, potentially due to intra species competition