Multi-scale patterns of habitat use by re-introduced mammals: A case study using medium-sized marsupials

Knowledge of the habitat requirements of threatened species at both local and landscape scales is crucial for maintaining viable populations and for making conservation and management decisions. Here, we use live trapping and radio-tracking to investigate habitat use by four species of threatened marsupials - burrowing bettongs (Bettongia lesueur), brush-tailed bettongs (B. penicillata), greater bilbies (Macrotis lagotis), and bridled nailtail wallabies (Onychogalea fraenata). The study populations had been re-introduced to Scotia Sanctuary in western New South Wales, Australia, within a predator-proof area. All showed preferences for particular macrohabitats while resting by day, with M. lagotis and B. penicillata selecting Eucalyptus woodland with Triodia understorey and B. lesueur and O. fraenata selecting Eucalyptus woodland with shrubs. However, they showed no such partiality at night. Bettongia penicillata used areas with Triodia and litter but few herbs for shelter, while burrows of M. lagotis avoided shrubs. Habitat components that influenced trap captures were: crust cover and herb layer cover (negative) for B. penicillata, trees <5 m in height and number of shrubs (both negative) for B. lesueur, crust cover for M. lagotis, and crust cover and trees <5 m high for O. fraenata (both negative). There was also a negative association at this scale between B. penicillata and both B. lesueur and M. lagotis, suggesting the possibility of competition. Our results support the idea that studies at multiple spatial scales are crucial to understand the habitat use and requirements of threatened fauna, and should therefore be incorporated into future re-introduction programs.