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Biosecurity news

Biosecurity news

Updated 20 October 2021 11:35am

 Work to manage pest plants and pest animals across our region continues year round. It’s hard work but every little difference we all make has a huge impact on protecting our native flora and fauna and ensuring a healthy place for us to live.

Here’s some news about some of the work underway:

 Aerial pest plant spraying at Whitireia Coast, Key Native Ecosystem

An aerial spray operation is planned on a variety of pest plant species on the cliffs and some slopes of Whitireia Park between February to June 2020. The site is one of our Key Native Ecosystems which are important coastal biodiversity areas across our region. This site is currently under threat from invasive, exotic species.

The operation will take place when weather conditions allow, on a week day only and not during school or public holidays. 

The park will remain open during the operation with the exception of Te Onepoto stream track while spraying in adjacent areas takes place. There will also be some restriction to access of cliff tops while spraying occurs on the escarpments.

The herbicide used will be Tordon Brushkiller XT. All sensitive areas such as the ocean and public access routes are well away from the spray zone.

To find out more about this and other pest plant operations, contact us on 0800 496 734 or email

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 Predator Free Wellington – Stage 1: Miramar

As a result of our intensive three year possum control programme Wellington’s Miramar Peninsula is now possum-free.

Now we're targeting rats, stoats and weasels. This involves lending our technical expertise and time to support the mahi of Predator Free Wellington and the thousands of volunteers involved.

Find out about our work with Predator Free Wellington on the Miramar Peninsular.

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 Managing pests in a mast year

Credit: Department of Conservation

Our biodiversity people have been monitoring the mega mast - bumper crop of seeds from beech, podocarps and broadleaf trees - in East Harbour Regional Park. There is likely to be a ‘mega mast’ with masses of food for rats and stoats and their populations are expected to boom.

We will continue to monitor the situation closely and are ready to control these pests before they damage our forests and animals.

Find out more about ongoing operations to manage pests.


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 Winter weeding - top tips to keep pest plants away

Winter is the best time to target pest weeds in your backyard. The annual weeds and leaves of deciduous plants are out of the way so you’ll be able to see more clearly and access will be easier. 

“If you’re weeding and there are intact seedheads, cut these off or remove them carefully and bin them. It’s best to take them to your local landfill and keep weeds with seedheads or bulbs, roots (and rhizomes) out of the compost. They will quite happily grow, especially when shifted to a nice new garden bed” - Katrina Merrifield, Biosecurity Advisor at GWRC

Winter is not the best time of year to spray anything with herbicide as plants are generally quite inactive if not dormant, so herbicides won’t travel round the plant well.

Here are some top tips from our Biosecurity team to deal with some of our invasive pest plants:

  • Tradescantia (wandering willie): Tackle large infestations by raking and rolling up the matted growth. Work from the top of the area downwards, and from the edges to the centre. This will reduce the amount that needs to be sprayed in spring. Find out more
  • Old man’s beard: Trace the plant back to the soil, cut off and paste with herbicide gel (eg/ Bamboo Buster ® , or Vigilant II® gel).  This is a good way to take on large plants. Check for any regrowth and repeat this in spring. Find out more
  • Italian arum: These flower over winter so it’s a good time to dig the bulbs out as you can see them easily. See Weedbusters for more information
  • Blackberry: Prepare large patches by slashing the canes down to about a metre in length. In spring when the leaves emerge you can come straight in and spray effectively. Find out more

See more information about pest plants and tips 'n' tricks to control them.

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 A biosecurity team of 4.7 million

Every New Zealander has a role to play in preventing pests and diseases from getting into New Zealand, or helping to stop their spread if they do get here. It takes all of us to protect what we’ve got – that’s a biosecurity team of 4.7 million people.

Biosecurity New Zealand is leading the Ko Tātou This Is Us project which asks us to take a moment to think about how biosecurity protects our way of life, the outdoor environment where we fish, farm, hunt and explore, the beautiful biodiversity of our unique ecosystem and even the food we eat.

See Ko Tātou This Is Us for more information.

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 Fern birds thrive after pest control in Pauatahanui Wildlife Reserve

Pest control is working its magic in our region with Fernbirds “singing away” in the Pauatahanui Wildlife Reserve.

Following the release of these at-risk and declining birds by Forest and Bird in 2017, we installed a large number of traps in surrounding areas. This is part of a predator program to protect the Porirua Harbour. Find out more.

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 Trapping trial in Te Ahumairangi (Tinakori) Hill

Credit: Wellington City Council

On the 116ha Te Ahumairangi (Tinakori) Hill we’re part of a trial to see if we can control rats without the use of poisons.

Working with Wellington City Council we replaced half of the 70 bait stations with twice as many self-setting traps, leaving the other half as poison bait stations around the outside of the site.

The traps are checked every three months, with a full service, replacing lures and gas bottles every six months

Every three months the site is monitored to detect the presence of rodents. Chew cards help us understand which pests are 'visiting' these traps. The pests bite the card and then we can look at the teeth marks. We also use an ink card in the trap tunnel. The animal enters the tunnel, lured in by some peanut butter, and we can look at the prints they leave behind.

So far the results of this trail have been extremely positive and rat numbers remain low. A wide range of birds can now be heard in the area, including migrating birds from Zealandia such as Kaka

The next step is to replace the remaining bait stations with the self-setting traps to see if we can keep reduced rat numbers.

Find out about trapping.

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 Protecting Porirua Scenic Reserve

Credit: Porirua City Council

More than 315 hectares of Porirua Scenic Reserve, and the adjoining Rangituhi/Colonial Knob Scenic Reserve in Poriua City are benefiting from pest plant and animal control.

This site is the most significant area of native forest left in the Tawa–Porirua Basin. It is a rare example of lowland forest supporting five species of podocarp, coastal kohekohe and tawa.

In partnership with Porirua City Council we are targeting tradescantia (wandering willie), old man’s beard, gorse, broom, possum, stoat, hedgehog, pest cat, rats, and stock that occasionally finds a hole in the fence. Some pines have been removed but are common near the top of Porirua Scenic Reserve.

Pest control started in 1996 and we now have 214 poison bait stations over 20km to control possums and rats, and 31 traps targeting stoats. All of these are checked and serviced by our team every three months.

Since our pest control work started there has been a significant increase in birds such as tui, kereru, grey warbler, and self-introductions of bell bird kakariki, which are now seen regularly.

See more information about this and other Key Native Ecosystem sites.

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