Lethal control of semi-arid, red fox populations fails to reduce their abundance but may create increased fox activity

Abstract Biological invasions threaten biodiversity globally. In Australia, introduced and invasive European red foxes (Vulpes vulpes) are a major predator of native wildlife, and are implicated in numerous species extinctions, prompting large-scale fox population control programs. Lethal control—typically via poison (1080) baiting—is common, but the consistency of its efficacy has been questioned, and the desired outcomes are frequently not measured or evaluated. We aimed to assess the success and impacts of lethal fox control on fox activity, and subsequent effects on a co-occurring, invasive mesopredator (feral cat, Felis catus), and native and invasive prey species. We surveyed three locations in the Wimmera region of Victoria, each experienced a different baiting regime (no baiting, standard systematic baiting, intensified baiting). Camera traps were deployed from April 2021 to August 2023 to determine predator activity alongside non-target herbivores. Baiting treatment was not associated with differences in fox or cat activity. Nurcoung (no baiting) had the lowest activity of both cats and foxes across the study. Fox activity patterns under standard baiting were higher than intensified baiting. Our results suggest that fox control might destabilise population dynamics of foxes, potentially facilitating increased activity levels through higher emigration rates from the surrounding agricultural environments. Our study highlights the critical importance of appropriately monitoring the outcomes of invasive species control programs to ensure the a priori strategic objectives are achieved. To achieve more effective fox population suppression broader, landscape-scale approaches that take a nil-tenure approach are essential.