Invasive species in New Zealand

A number of introduced species, some of which have become invasive species, have been added to New Zealand's native flora and fauna. Both deliberate and accidental introductions have been made from the time of the first human settlement, with several waves of Polynesian people at some time before the year 1300, followed by Europeans after 1769.

Almost without exception, the introduced species have been detrimental to the native flora and fauna but some, such as farmed sheep and cows and the clover upon which they feed, now form a large part of the economy of New Zealand. Registers, lists and indexes of species that are invasive, potentially invasive, or a threat to agriculture or biodiversity are maintained by Biosecurity New Zealand.

Many invasive animal species are listed in schedules 5 and 6 of the Wildlife Act 1953. Those in Schedule 5 have no protection and may be killed. Those in Schedule 6 are declared to be noxious animals and subject to the Noxious Animals Act 1956. In 2016 the New Zealand government introduced a policy of eliminating all non-native predators (such as rats, possums and stoats) by 2050.

Some of the better-known invasive animal species are as follows.

The National Pest Plant Accord, with a listing of about 120 genus, species, hybrids and subspecies, was developed to limit the spread of plant pests. Invasive plants are classified as such on a regional basis with some plants declared as national plant pests. The Department of Conservation also lists 328 vascular plant species as environmental weeds.

Some of the better-known invasive plant species are:

The city of Auckland has been declared to be the weediest city in the world.

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