When people introduce plants and animals to new area, it most often goes wrong. The classic disaster was Thomas Austin bringing cute and “huntable” English rabbits to Australia; they devastated the landscape.
The mistake was repeated in bringing in cane toads, Rhinella marina, from South America to control sugar cane beetles. The toads are protected from predators by very poisonous secretions on their skin. Their populations exploded. Control by humans did little. The effects on native animals – and humans' pets - trying to “do their part” (well, just trying to earn a living) by eating the toads are horrific.
Toads look like a nice meal for animals such as the big goanna lizards – to the rescue! However, goannas commonly die when they try to eat the cane toads. The population of the yellow-spotted goanna has gone down to 1/10 of its original size.
Now, researchers have published a novel and counterintuitive approach, not to eliminate the toads, but at least to save the lizards. They release eggs, tadpoles, and young toads where the goannas are gonna go (sorry; the pun was unavoidable). The lizards get very sick on eating the bait, but they learn. The method was tested where cane toads started invading. Researchers put out the bait and monitored the lizard populations with infrared motion-detecting cameras. Comparing areas with and without bait, it’s clear: Aha! It works.
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: Scientific American, July/August 2024, pp. 13-14.
