The ecological influence of foxes is context dependent. Dingo persecution, fire, land clearing, habitat fragmentation and grazing all pave the way for fox population irruptions and to conditions that make small mammals vulnerable to predation. Dingoes, in particular, are highly effective at limiting fox populations. In fact, the very method used to control foxes - 1080 poison baiting - ironically causes fox population irruptions, because 1080 kills dingoes too. Dingoes do not eradicate foxes, but they do limit their density, restrict their movement and change their behaviour.
What are the ecological benefits of foxes when their densities are sustainable? Well, the same benefit they provide in their native range: they help limit populations of smaller predators and prey. Australian islands with foxes have had fewer extinctions than those without because they help suppress rats. Killing foxes also leads to irruptions of cats and rabbits, to the detriment of small native mammals and plants.
Killing foxes has failed to suppress fox populations, it does not help recover native prey, nor does it reduce fox predation on lambs. The conservation of dingoes, and the protection of habitat, are the most powerful ways to help foxes and native prey coexist.
By Arian Wallach