Macquarie Island can serve as an example of what not to do with invasive species. Trouble began almost as soon as seal and penguin hunters began to use the island near Antarctica as a base of operations in the early 1800s. Rats and mice jumped from the ships and infiltrated food stockpiles, so the sailors brought cats ashore. Later, rabbits were introduced for meat.

But the feral cats were preying on the island's native birds, and in the 1980s conservationists began a major effort to kill all the cats. By 2000, it was done. But once this predator was removed, the rabbit population exploded. Scientists recently announced that the 100,000 hungry rabbits have denuded the landscape of vegetation, and say it will cost $17 million to get rid of the invaders and re-establish native plant life.

Status: Screwed Up, and Working on Fixing It