 Introduced herbivores may unbalance the ecology of islands; introduced rabbits destroyed the forest understory on Cabbage Tree Island off New South Wales, which increased the vulnerability of the Gould's petrels nesting on the island to natural predators, and left them vulnerable to the sticky fruits of the native birdlime tree (Pisonia umbellifera). In the natural state these fruits lodge in the understory of the forest, but with the understory removed the fruits fall to the ground where the petrels move about, sticking to their feathers and making flight impossible.
