Interactions between a Top Order Predator and Exotic Mesopredators in the Australian Rangelands

Abstract

An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.

Ecology and predator associations of the northern quoll (Dasyurus hallucatus) in the Pilbara

“…Dingoes are successfully controlled using baits, while cats are more selective, less likely to eat carrion, and therefore less likely to consume baits (Claridge et al 2010). Current widespread control efforts are selective against dingoes and have led to mesopredator release of cats (Glen et al 2011;Moseby et al 2012). This was also evident in my study area (Chapter 2).…”

“…In Australia, Cupples et al (2011) found extensive dietary overlap between dingoes and foxes (Pianka's index > 0.84), and found evidence of dingoes killing foxes. There is also experimental evidence of dingoes killing cats (and foxes) resulting from interference predation (Moseby et al 2012). And, cats have been documented killing quolls (Doherty et al 2015a).…”

“…During their study, Brawata and Neeman (2011) found evidence supporting indirect mechanisms, where dingoes deterred cats and foxes from areas near artificial water points. However, dingo predation has also been recorded on cats (Allen et al 2015;Moseby et al 2012) and foxes (Cupples et al 2011). Moseby et al (2012) found direct killing without consumption, and deaths occurred during high activity times, suggesting that dingoes opportunistically kill cats and foxes through interference competition rather than predation.…”

“…1080 is known to affect some quoll species (Belcher 1998;Hill and Ward 2010), but King (1989) found no evidence to support a deleterious effect of 1080 on northern quolls in the Pilbara. This poison can control foxes and cats as well as dingoes; however cats are more selective than foxes, making them less likely to consume 1080 bait (Claridge et al 2010;Moseby et al 2012). …”

“…Consequently, control practices are not effective at lowering cat numbers, generating mesopredator release where cats thrive in the absence of foxes and dingoes (Glen et al 2011;Moseby et al 2012). This appears to have resulted in a rise in cat numbers following continent-wide efforts to control dingoes ).…”