Predator and herbivore occupancy and habitat use in response to fox baiting in the Little Desert, Victoria

Introduced predators have been implicated in the decline and extinction of many species worldwide, and their effects on ecosystems can also be severe. In Australia, the introduced red fox (Vulpes vulpes) and feral cat (Felis catus) have had a devastating effect on native wildlife, particularly mammals. Attempts to mitigate their impacts, in the form of lethal control programs, have had mixed results. Managing these pests has been confounded by a lack of consideration for species interactions and processes (e.g. mesopredator release), and environmental factors such as habitat variation and fire regimes. Effective, long-term, evidence-based monitoring of invasive predator management is urgently needed but typically lacking. I used a Before After Control Impact (BACI) experiment to assess the efficacy of intensified fox baiting and its outcomes in the semi-arid Little Desert National Park, in western Victoria. Using on-track camera traps and scat transect surveys, I estimated site occupancy, detectability, temporal overlap, spatial activity, and the influence of environmental variables on predators and common prey species. Fox occupancy was very high (95-100%) and remained constant throughout the sampling period, despite intensified fox control. Both cat and prey occupancy and detectability remained relatively constant, and fire, vegetation type and distance to agriculture were stronger influences on all species than the treatment variables (season and location). There was some evidence suggesting temporal avoidance of predators by prey, and seasonal and locational changes in species’ spatial activity and temporal overlap. My study emphasises the importance of considering ecological interactions during invasive predator control programs and the need for continued and effective monitoring to examine if changes in species’ activity or occupancy are a result of environmental factors, baiting effects, or a combination of both.