Scotland, United Kingdom
Australia has an extinction problem similar to New Zealand's. About 30 to 40 species of mammals are either totally gone or restricted to small areas; there have been huge range reductions due to introduced fox, rabbit, and other mammals. When rabbits became a problem, the fox was introduced in an attempt to control them. The fox did little to control rabbits but a lot to kill off small to medium- sized native mammals. There is now an attempt in Western Australia to try to increase the ranges of some these endangered native mammals by breeding and reintroducing populations while controlling predators.
The first step is to control predators (foxes) with aerial broadcasting of the poisonous chemical "1080". In Western Australia this chemical occurs naturally in native plants so native animals aren't effected, while nonnatives are killed. No ecosystem effects have been detected thus far from the use of 1080 in Western Australia, perhaps because it exists naturally in this ecosystem. (1080 cannot be used in areas in which the chemical does not occur naturally or it would kill off native animals as well as invaders.) Step two is to reintroduce mammals from islands and set up exclusion zones and buffer zones to keep foxes out. However, as you control foxes, feral cat populations expand. Cats won't take the poison bait so they haven't yet figured out to control them. Cats harm native animals as well, and there is now a movement to support more wildlife and fewer cats.