Do introduced apex predators suppress introduced mesopredators? A multiscale spatiotemporal study of dingoes and feral cats in Australia suggests not

Abstract

1. The role of apex predators in structuring ecosystems through the suppression of mesopredator activity and abundance is receiving increasing attention, largely due to the potential benefits for biodiversity conservation. In Australia, invasive mesopredators such as feral cats (Felis catus) have been identified as major contributors to Australia's mass mammal extinctions since European arrival. The introduced dingo (Canis familiaris) has been proposed as a novel way to suppress the impacts of feral cats, however, scientific evidence of the dingo's suppressive role is equivocal.2. We used camera traps to investigate whether a large introduced predator (dingo) suppresses the activity of an established introduced mesopredator (feral cat) across a national park site conserving endangered species, and an agricultural site supporting cattle grazing enterprises.3. Feral cats and dingoes exhibited marked overlap in both temporal and spatial activity, indicating coexistence. Some temporal separation was evident at the agricultural site, however, this reflected higher diurnal activity by dingoes, not a responsive shift in cat activity. Cat activity times were unrelated to dingo presence and did not differ between areas occupied by dingoes and dingo-free areas.There was no evidence of dingoes excluding cats from patches at either site, nor was there evidence of within-night fine-scale spatiotemporal avoidance of dingoes by cats. 4. Species co-occurrence models revealed dingoes had no negative effect on the probability of cat presence. The probability of detecting a cat on the national park was significantly higher in areas with dingoes than in dingo-free areas, while on agricultural land, cat detectability did not differ between areas with and without dingoes. Cats remained active, abundant and widespread across both sites, with evidence of cats hunting and breeding successfully in areas occupied by dingoes. Synthesis and applications.Our findings indicate that feral cats can coexist with dingoes, without apparent suppression of cat activity, abundance or fitness.Proposals to reintroduce or restore dingoes and other large predators to suppress invasive mesopredators and conserve biodiversity should be carefully evaluated | 2585Journal of Applied Ecology FANCOURT eT Al.

Space use and interactions of two introduced mesopredators, European red fox and feral cat, in an arid landscape

“…(2020) in western Victoria, but contrasts with the results of Fancourt et al. (2019) that found little diurnal activity by feral cats during winter months. Elsewhere, feral cat diel activity has also been shown to vary with seasonality (Wang and Fisher 2012).…”

“…2017 a , Fancourt et al. 2019). The analytical framework presented here can readily be applied to landscapes with dingoes, foxes, and cats, and inform the current debate, and subsequently guide management options for introduced predators throughout Australia and elsewhere.…”

Identifying mesopredator release in multi‐predator systems: a review of evidence from North America

“…dingo, jackal Canis spp.) provide a valuable test of MR as a working ecological theory that is testable across systems with different ecological contexts (Fancourt et al 2019). Further, such information could be vital for creating informed management plans for mesopredator species and for the critical evaluation of the goals and effectiveness of ongoing widescale control or eradication programmes (Gompper 2002, Gehrt & Clark 2003).…”

Short‐term response of threatened small macropods and their predators to prescribed burns in subtropical Australia

“…Foxes and cats can have major impacts on medium‐sized mammals in some ecosystems (Kinnear et al 1988; Short & Smith 1994; Kinnear et al 2002; Doherty et al 2015; Radford et al 2018), but because they were rarely detected in burn blocks following prescribed burns, these mesopredators would have little impact at our sites. Some studies have reported that the Dingo populations may have a suppressive effect on mesopredators including cats and foxes (Johnson & VanDerWal, 2009; Brook et al 2012); however, see Fancourt et al (2019). This may explain the negligible activity of foxes and cats in our study; however, our data did not allow exploration of these relationships.…”