Long-term and large-scale control of the introduced red fox increases native mammal occupancy in Australian forests

Abstract

Management agencies commonly control non-native mammalian predators to protect native prey populations, but there are few robust examples of such control enhancing native prey populations. We conducted a 9-year landscape-scale management experiment to evaluate the benefits of controlling the invasive red fox (Vulpes vulpes) to low densities for three native ground-dwelling mammalian prey species—common brushtail possum (Trichosurus vulpecula), long-nosed potoroo (Potorous tridactylus) and southern brown bandicoot (Isoodon obesulus)—in south-east Australian forests. We hypothesized that sustained and spatially extensive fox control would reduce fox abundance and increase occupancy, colonization and persistence rates for all three prey species in three treatment areas relative to three non-treatment areas. There was a substantial decline in bait take by foxes in treatment areas from 2005 to 2013, and fox abundances were much lower in treatment than non-treatment areas throughout the experiment. Occupancy rates of all three native prey species increased in treatment areas relative to non-treatment areas, although the magnitude of the increase varied with species, treatment area, and time. Colonization and persistence rates were not always positive for all species and all treatment areas. Our experiment demonstrates that foxes can be reduced to, and maintained at, low abundances and that this has a generally positive effect on the occupancy by small native mammalian prey species.