Over the last 200 years, the distribution and abundance of critical-weight-range mammals in Australia has declined, with many species now locally extinct or confined to small isolated refuges. In 2005, the bilby (Macrotis lagotis), bridled Nailtail wallaby (Onychogalea fraenata) and numbat (Myrmecobius fasciatus) were reintroduced into part of their former range, a predator-free 8,000 hectare area of conservation fencing at Scotia Sanctuary in south-western New South Wales. Our study follows previous work on the habitat selection of these species conducted upon release 10 years ago (Finlayson et al. 2008). Our study examined differences in habitat selection for these species following multiple generations in a predator-free and area-restricted environment.
We used spotlighting data over 3 seasons at Scotia Sanctuary to identify habitat preferences for these species. We used a Utilization Distribution (UD) analysis to test habitat preferences within the fenced enclosure. We created kernel density estimates (KDE) from spotlighting location records for each species, taking into account detectability, the restricted area and location of the fence. We then used quasi-poisson generalized linear mixed models with the density scores for each species fitted as the response variable, and habitat type fitted as a predictor variable, with distance from spotlighting transect fitted as a random effect.
Our findings will be used to inform future translocations, fence locations and outside-the-fence releases of these species. Identifying how the habitat preferences of these species differ in the absence of key threats is critical to understanding how predator-free areas of conservation fencing can be used in a recovery and re-wilding context.