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Biosecurity activities

Invasive plant and animal pests are destroying our native vegetation and threatening economic production at an alarming rate. There are 85 plants and 22 animals that are declared 'pests' in the Waikato region. Find out more about plant and animal pests in our region, why they are pests and what we can do to help control them.

Photograph of 'Woody Weed'

What makes a pest a ‘pest’?

Plant and animal pests are species that have been introduced to New Zealand and threaten our native plants, animals and natural habitats. Plant and animal pests have become the greatest single threat to our native plants and animals.

Plant pests threaten our native plants by smothering, strangling or crowding them out. Eventually plant pests can take over our forests and wetlands. Many are also a nuisance to farmers, in suburban gardens and may cause health problems for some people.

Animal pests threaten our region's native ecosystems, such as forests and wetlands. Some animal pests, such as feral goats and possums, destroy plants by eating their leaves, flowers or fruit. Other animal pests, such as stoats and rats, eat our native birds or their eggs as well as native lizards, frogs and insects.

Many animal pests are also a nuisance to farmers, in suburban gardens and businesses. For example, goats create erosion on riverbanks, and possums carry bovine tuberculosis (Tb). Bovine Tb is a disease that affects farm animals and threatens our export markets.

Pest fish also affect our waterways, such as lakes and rivers.

Pests affect our cultural heritage

Maori have strong cultural, traditional and historic links with wetlands and inland waterways, including lakes, rivers, streams and springs. These taonga (treasures) are spiritually significant and closely linked to the identities of the tangata whenua (people of the land).

Taonga species used for food or materials have been threatened and in some cases destroyed, often by pests. This has had a dramatic effect on the values and identity of Maori.

Introduced fish such as trout and catfish have caused a decline in local food sources such as freshwater crayfish (koura) and crab, dwarf inanga, giant kokopu, brown mudfish and eels.

The coastal plant pingao used for decorative work in wharenui has struggled for survival due to the planting of introduced plant species such as marram and lupin.

Economic cost of pests

The economic cost of pests to New Zealand is more than $840 million a year – that’s one per cent of our gross domestic product. The cost of pests to the Waikato region is estimated to be more than $84 million a year.

This is because plant and animal pests affect our:

  • natural environment
  • unique ecological and cultural heritage
  • primary production industries
  • economy.

Animal pest activities

How many animal pests can your class identify? Remember that animal pests can be mammals, marsupials, birds, insects or fish.

Get your class to think about why they are pests.

  • Where do they live?
  • What do they eat?
  • What damage do they do to the land, waterways, other animals or plants?

Check out our information about animal pests.

Once your class has become familiar with animal pests, get them to make ‘wanted’ posters for different pests. Which pests would you choose? What do they look like? Why are they pests?

Plant pest activities

Use our Plant Pest webpages to learn about the different plant pests in our region. You’ll learn how to recognise them, why they are pests and how to control them.

Get your class to think about the key features that contribute to these plants being pests. For example you could think about their growth habits (thick bushy clumps, vines, fast-growing trees), how they spread and the different growing conditions they can tolerate.

Can you see any of these plants growing in your school grounds, in your local park or at home? Ask your class what they think they should do if they see them.

What plants are pests in your area? Your class could make ‘wanted’ posters for them. Which pests would you choose? What do they look like? Why are they pests?

Visit the Weedbusters website for more information on plant pests, weed activities, and to find out about Weedbusters events across New Zealand. Contact the Weedbusters Regional Coordinator on Waikato Regional Council's Freephone 0800 800 401.