Using a native predator (the meat ant,Iridomyrmex reburrus) to reduce the abundance of an invasive species (the cane toad,Bufo marinus) in tropical Australia

Abstract

Summary1. Invasive species pose ecological threats in many areas, but attempts to control invaders by introducing other exotic species may cause further unanticipated problems. If we can use predators native to the introduced range to assist in control of the invader, the risks of collateral damage are lower. 2. In tropical Australia, high desiccation rates restrict newly-transformed (metamorph) cane toads Bufo marinus to the margins of waterbodies, rendering the metamorphs vulnerable to predatory ants (Iridomyrmex reburrus). By adding bait (catfood) to selected areas, we increased ant densities (and thus, toad mortality) more than fourfold. 3. Over 50% of attacks by ants in the field were immediately fatal to the metamorph toads, and most 'escapee' toads (88%) died of their injuries within 24 h after the attack. 4. When we increased ant densities by artificial baiting, 98% of metamorph toads were encountered, and 84% attacked, within the two-minute observation period. Collateral damage to native fauna appears to be low, but warrants closer examination. 5. Synthesis and applications. Manipulating the foraging locations of native predatory ants can substantially increase their off-take of invasive toads. More generally, vulnerabilities of invasive species to predators native to the introduced range may facilitate control of invader numbers with little collateral damage to the rest of the fauna.

Variation in native micro-predator abundance explains recruitment of a mobile invasive fish, the common carp, in a naturally unstable environment

“…Although it has been previously demonstrated that native predators can control invasive invertebrates and amphibians (Hill and Lodge 1999;deRivera et al 2005;Ward-Fear et al 2010), our study appears to provide the first direct evidence for a fish. Using both correlative analyses and controlled experiments in complex and large systems, we demonstrate that although carp exert high propagule pressure across wide range of habitats, they successfully recruit only in lakes that experience severe instability events (in this case winterkills).…”

Excluding access to invasion hubs can contain the spread of an invasive vertebrate

“…A growing body of research now indicates that toad populations and impacts can in some areas be managed using physical control and by manipulating the behaviour of predators that attack toads ( [48,49]; this study). While we do not propose water exclusion as a 'silver bullet' for toad control, our study shows that exclusion of toads from AWPs can effectively reduce toad numbers and could prevent their overland spread in arid regions.…”

Ecology, Impacts, and Management of Invasive Rodents in the United States

“…Cat food bait was successfully used to recruit predatory ants (Iridomyrmex reburrus) to water edges where newly morphed cane toads had emerged (Ward-Fear et al 2010). Additionally, taste aversion to cane toads has been trialed successfully in Australia and has potential as a management technique to bene t cane toad-threatened fauna.…”