Pests that have established themselves in New Zealand require strategies and programmes to manage their risk to our environment. Below is a collection of pests and diseases that are currently being managed in New Zealand.
In New Zealand, trap use is regulated by the Animal Welfare Act 1999. This Act permits any trap to be used for trapping any species, but it also enables the Minister of Agriculture to recommend to the Governor General traps that should be prohibited because they cause unacceptable pain and suffering.
Feral goats can quickly destroy all vegetation within their reach, threatening native plants and damaging the forest understorey.
Feral pigs impact native ecosystems, pastoral production and contribute to the bovine tuberculosis (Tb) problem. Pigs can damage pasture and crops, and kill newborn lambs and cast sheep. However, the extent of such damage is limited in New Zealand.
Feral cats have a major impact on New Zealand’s native and non-native species. The basis of their diet alters with the habitat they live in. They feed on rabbits, birds and bird eggs, rats, hares, bats, lizards, mice, wētā and other insects.
Deer are selective browsers and target particular forest species over others. This can result in significant changes to forest composition and has effects on the fauna that rely on those plants.
Three species of Mustelids occur in New Zealand, the ferret, the stoat, and the weasel. Ferrets are a significant pest preying on indigenous wildlife and can carry bovine tuberculosis (Tb). Stoats are the most numerous predator of native birds. Weasels are less numerous but pose similar threats.
Possums are an economic threat to New Zealand farmers as they carry and spread Bovine tuberculosis (Tb), a disease that can affect humans, as well as stock. They also cause damage to agriculture, horticulture, forestry and natural ecosystems.
Rooks and Australian magpies are both aggressive birds known to raid the nests of native birds, destroy eggs and tip out fledglings.
Freshwater ecosystems are vulnerable to invasion by pests and weeds because it is very hard to detect them until they are a problem. In recent years there has been a rapid expansion of some species of introduced freshwater fish.
Rats have been introduced across the globe by human activities. They threaten the survival of many native species from invertebrates like wētā and snails to lizards and birds. In NZ the ship rat and the Norway rat are the most common.
Dama and Bennett’s wallabies are a pastoral and environmental pest in New Zealand, grazing on grasses and on native vegetation. When present in high numbers they can cause considerable damage to native species, altering the present and future composition of native forests.
Wild rabbits are one of the most serious agricultural and environmental pests in New Zealand. Whilst not predators, they do damage habitats and crop yields significantly.
New Zealand has several kinds of native wasps which have evolved here and have never become a nuisance. But five social species of wasps have been accidentally introduced since the 1940s and are classed as pests (German and common wasps, and three species of paper wasp).