Their gland secretions are toxic to many predators, and some naïve populations have locally declined. They have never caused extinctions however, and although declines can be sharp, they tend to be temporary.
Life is remarkably adaptable, and toads have become an engine of evolution. Some native snakes have undergone rapid adaptation to cane toads, reducing the size of their mouths relative to the size of their bodies, so that they are now able to tolerate the amount of toxin ingested. Other species, including several native birds, have learned how to hunt cane toads successfully by avoiding the toxic glands and eating the rest. And yet others simply learn to avoid them, and hunt someone else. These extraordinary examples of rapid evolution have resulted in the recovery of native predator populations from initial declines. Human efforts to control toads have not been helpful.
Toads are opportunistic predators that can help regulate potentially irruptive invertebrates and small vertebrates. As prey, they benefit a range of predators once the adaptation to their toxin occurs. But like any species, ecological benefits come from sustainable densities, and thus biodiversity increases when the predators of cane toads are abundant. And this is where the dingo can help.
Large predators regulate species both directly by hunting them, and indirectly by promoting the diversity of their predators and competitors. When dingoes suppress mesopredators (e.g. foxes and cats) and herbivores (e.g. rabbits and kangaroos), they indirectly benefit the populations of a variety of other species. Some of which are toad predators.
By Arian Wallach