Over the past 200 years, a number of alien invertebrates, mammal and bird species have been introduced to Macquarie Island. Some have had serious impacts on the island's native flora and fauna.
Horses, donkeys, pigs, cattle, goats, dogs and sheep are long gone, and between 1989 and 2000, weka and cats were eradicated. A major project to remove the last remaining mammal species - rabbits, ship rats and mice was undertaken between 2007 and 2014. Aerial baiting of the entire island was completed in July 2011, followed by intensive monitoring by hunters and highly trained detection dogs, to detect and dispatch any surviving individuals.
In April 2014, after nearly three years of monitoring with no sign of surviving individual rabbits, rats or mice, the project was declared a success.
With the removal of rabbits and the resulting intensive grazing pressure, the island's vegetation is rapidly rebounding. Sea birds, which had suffered predation of eggs and chicks by rats, are also returning in numerous areas. Invertebrates too, are recovering, with spider webs now being seen amidst the vegetation and moths far more prevalent on the plateau.