Ngā kīrearea otaota, kīrehe hoki Plant and animal pests

• Plants

Manchurian wild rice

Manchurian wild rice is a very invasive, tall non-native grass that takes over areas of land and shallow water. It has been found in Northland, Auckland, Waikato and Greater Wellington regions, growing next to riparian areas of rivers, lakes and drains, in swamps and on low-lying farmland.

• Plants

Wilding pines

Wilding conifers mainly establish as a result of natural seed spread. This process has been exacerbated by occupiers failing to act when wilding conifers first occur, and much of the ongoing wilding conifer spread in New Zealand is generated from existing areas of reproducing wilding conifers.

• Diseases
• Plants

Dutch elm disease

Dutch elm disease (DED) is considered one of the most devastating tree diseases in the world. Unfortunately DED has spread into the north Waikato and it has currently spread as far south as Huntly.

• Plants

Fine stemmed needlegrass / Mexican feather grass (nassella)

Fine stemmed needlegrass / Mexican feather grass is a densely tufted grass that invades pastures and grasslands. It is native to parts of Argentina, Mexico and the southern United states and has been incorrectly sold in New Zealand nurseries as a native grass.

• Plants

Wild kiwifruit

Wild kiwifruit can grow in a wide range of habitats including native bush, pine forest, shelter belts and gullies. If left uncontrolled, it can form dense, heavy blankets of vines that strangle trees, causing them to die or fall. As such it is a significant potential threat to native ecosystems and plantation forest in many parts of our region. It also has the potential to impact on taonga species

• Aquatic
• Plants

Mexican water lily

Mexican water lily, a native of the Southern United States and Mexico, is a floating aquatic plant that was introduced to New Zealand as an ornamental pond species. It’s recognisable by its large, flat, leathery floating spotted leaves and yellow flowers.

• Plants

Gorse

Gorse was introduced to New Zealand from western Europe in the early 1800s. Originally used for hedging and windbreaks, it has long been recognised as a pest plant and is widespread in the Waikato region.

• Animals

Feral cats

Cats prey on birds, lizards and frogs, including many native species. Cats can carry tuberculosis, toxoplasmosis and parasites which are harmful to humans

• Aquatic
• Plants

Lindavia intermedia

Lindavia intermedia is a microscopic algae species that can cause lake snow – a sticky, mucus-like substance that hangs under the water. Lake snow sticks to fishing gear and boat hulls, clings to swimmers, and can clog boat and water supply filters.

• Plants

Woolly nightshade

Woolly nightshade is a rapidly growing shrub or tree that grows to 9 metres tall. In large numbers it can rapidly invade poorly managed land and forest margins, where it can totally exclude the regeneration of native plants.

• Aquatic
• Plants

Yellow flag iris

Yellow flag iris is native to Europe, Asia and North Africa. Introduced to New Zealand as an ornamental plant, it has since spread to sites throughout New Zealand. A semi-aquatic species it is a particular problem on stream, river and wetland margins and in swampy ground.

• Plants

Wild ginger

Wild ginger forms dense clumps in native forests, smothering young plants and preventing native seedlings from growing. This makes it a threat to native ecosystems. There are two types of wild ginger in New Zealand – kahili ginger, a native of India and Nepal, and yellow ginger, a native of India and Madagascar.

• Plants

Tutsan

Tutsan invades regenerating sites, forming dense stands which stop native plant seedlings growing. Tutsan also readily invades disturbed forest and shrubland, tussockland, bare land, rocklands, roadsides, coastal areas, steep banks, lightly-farmed land and riparian margins, including rocky and open streams.

• Plants

Velvetleaf

Velvetleaf is one of the world’s most invasive pest plants, damaging arable crops by competing with them for nutrients, space and water

• Plants

Thistle

Thistles (nodding and plumeless) are widespread agricultural pests in the Waikato region. They have unpalatable foliage and reduce pasture production.

• Plants

Ragwort

Ragwort has been long been recognised as an invasive agricultural pest plant. It has unpalatable foliage that is poisonous to stock, with heavy infestations able to reduce pasture production throughout New Zealand.

• Aquatic
• Plants

Senegal tea

Senegal tea is an extremely aggressive weed of wet marshy soils and freshwater that inhabits wetlands and still or flowing waters.

• Plants

Pampas

Common and purple pampas, both originally from South America, are large invasive grasses. They are a serious threat to natural areas like sand dunes, coastal cliffs, and stream banks and wetlands where their dense clumps can completely replace native vegetation.