Australian mammals are amongst the most threatened in the world. Predation by invasive cats and foxes has driven many species to extinction, and has caused rapid declines and extirpation among others. ManyAustralian mammals now only persist in a small number of refugial populations of few individuals with a high risk of extinction from demographic population failure and catastrophic events. The persistence of many Australian mammal species now depends on continuous management, and the creation of new populations through translocations into predator controlled areas. Predator exclusion fences have become pivotal for effectively abating the predation threat for remnant populations and translocations. However, translocations are notoriously costly and failure prone, making it particularly important to identify protocols that maximize the likelihood of success. Thorough assessments are therefore required to improve outcomes, but knowledge to make them is often lacking. In this thesis, I address key knowledge gaps associated with translocation and predator management for Australian mammals, with particular regard to conservation fences.In Chapter 2 I address the issue of uncertainty of the accuracy of habitat models. Reintroductions often rely on models to identify suitable habitat, and such modelling requires occurrence data from a representative sample of a species' niche. However, the historic distributions of species that have subsequently declined are often poorly sampled. Therefore, we need to know how thoroughly a species' historic distribution was sampled before habitat suitability models can be trusted. I propose and test a method for determining whether a species' niche is well sampled pre-decline for Australian marsupials, by comparing accumulation curves of niche volume when data are arranged in forward and reverse chronological order. I found that accumulation curves can be used to test if a species' niche is poorly sampled, and that poor association between chronologically and randomly arranged data implies an under sampled niche.A good understanding of how translocated animals use the space within a fence is crucial in making choices about its size. In Chapter 3, I investigate the spatial use of woylies (Bettongia penicillata) a species of acute conservation concern at the Australian Wildlife Conservancy's Scotia Sanctuary in the arid extreme of their known historic distribution. Using GPS tracking devices, I measured the movements of woylies in two adjacent fenced populations. The higher density population occupied foraging ranges similar in size to those previously reported (37ha) while woylies at lower density had homes ranges 2.5 times greater in size (96 ha).The woylies in the lower density population increased the size of their foraging range by covering more unique ground each evening, and spending more time further away from their nest. While the differences between the two populations are most likely related to density, it remains uncertain whether intraspecific competition or environm...