Distinctive diets of eutherian predators in Australia

Abstract

Introduction of the domestic cat and red fox has devastated Australian native fauna. We synthesized Australian diet analyses to identify traits of prey species in cat, fox and dingo diets, which prey were more frequent or distinctive to the diet of each predator, and quantified dietary overlap. Nearly half (45%) of all Australian terrestrial mammal, bird and reptile species occurred in the diets of one or more predators. Cat and dingo diets overlapped least (0.64 ± 0.27, n = 24 location/time points) and cat diet changed little over 55 years of study. Cats were more likely to have eaten birds, reptiles and small mammals than foxes or dingoes. Dingo diet remained constant over 53 years and constituted the largest mammal, bird and reptile prey species, including more macropods/potoroids, wombats, monotremes and bandicoots/bilbies than cats or foxes. Fox diet had greater overlap with both cats (0.79 ± 0.20, n = 37) and dingoes (0.73 ± 0.21, n = 42), fewer distinctive items (plant material, possums/gliders) and significant spatial and temporal heterogeneity over 69 years, suggesting the opportunity for prey switching (especially of mammal prey) to mitigate competition. Our study reinforced concerns about mesopredator impacts upon scarce/threatened species and the need to control foxes and cats for fauna conservation. However, extensive dietary overlap and opportunism, as well as low incidence of mesopredators in dingo diets, precluded resolution of the debate about possible dingo suppression of foxes and cats.

Land use and dingo baiting are correlated with the density of kangaroos in rangeland systems

“…It is likely that rather than avoiding agricultural land, the natural distribution of red kangaroos tends to end at the western boundary of the pastoral zone, which is approximately the 250 mm isohyet (Short et al 1983). After swamp wallaby (Wallabia bicolor), red kangaroo is the second most common prey consumed by dingoes across Australia (Doherty et al 2019;Fleming et al 2022).…”

“…1983). After swamp wallaby ( Wallabia bicolor ), red kangaroo is the second most common prey consumed by dingoes across Australia (Doherty et al 2019; Fleming et al 2022).…”

The animal welfare, environmental impact, pest control functions, and disease effects of free‐ranging cats can be generalized and all are grounds for humanely reducing their numbers

“…Cats remote from human habitation opportunistically hunt thousands of species, killing billions of animals annually (e.g., Fleming et al, 2022;Stobo-Wilson et al, 2021). Diet varies with locale (Bonnaud et al, 2011;Doherty et al, 2016Doherty et al, , 2017.…”

Mesopredator release among invasive predators: Controlling red foxes can increase feral cat density and alter their behaviour

“…Nonetheless, cats are one of the most widespread and damaging invasive vertebrate predator species (Doherty et al, 2017; Legge et al, 2020; Medina et al, 2011). As foxes are larger bodied and have high dietary overlap with cats (Fleming et al, 2022), the mesopredator release hypothesis (Soulé et al, 1988) predicts cat density will increase as fox populations are suppressed (Molsher et al, 2017). Mesopredator release of cats would likely dampen the conservation benefits of fox control, and could even worsen outcomes for some native prey species (Takimoto & Nishijima, 2022), as has previously been suspected (e.g.…”