One of the vertebrates that the toads would eat possibly. The roads weren't natural to the enviorment and were introduced to it as an invasive species, meaning the animals that were already in the enviorment might not know how to survive against them as they haven't hap experience with them before. That could lead to the toads easily being able to eat and then breed more toads, which then eat more of the butterflies, ladybugs, and caterpillars that would have little to no defenses against them prepared. Let alone, this could lead to the toads getting rid of nearly all or all of them.
