Find out about our control programmes covering aquatic weeds, terrestrial weeds and wilding pines, and pest animals
Our biosecurity work has different objectives depending on the site and the nature of the pest. In some areas, we aim to eradicate the pest, while in other areas our focus is on preventing it from spreading or minimising the impact of existing infestations.
Aquatic weeds affect a number of lakes and waterways around New Zealand. We have surveillance programmes to ensure other lakes and rivers remain clear of these weeds. Our control work focus on the Rotorua Lakes, Lake Wanaka, Lake Dunstan and Lake Benmore.
We target much of our work at two introduced species:
- oxygen weed (lagarosiphon major)
- hornwort (ceratophyllum demersum)
How we control aquatic weeds depends on the environment and the state of the weed beds.
Generally, we use herbicides for widespread infestations. In more closely confined areas, we weed plants by hand or suction-dredging.
Terrestrial Weeds and Wilding Trees
We target a range of land-based weeds, including:
- Old Man’s Beard
- nasella tussock
- briar rose.
A major focus is controlling wilding conifers in the South Island. Several conifer species were planted in the 1950s and 1960s to control erosion or as trial timber plantations. These trees spread rapidly and now cause significant environmental damage to New Zealand including:
- crowding out native vegetation
- reducing available grazing land
- increasing fire hazards.
We deal with wilding conifers in various ways, including hand cutting or spraying them with herbicide. The method used depends on the nature and accessibility of the terrain, and the resistance of certain species to herbicides.
Mid Dome Wilding Trees Charitable Trust
We are closely involved in dealing with a major wilding trees infestation covering almost 70,000 hectares around Mid Dome in Southland. This work is coordinated by the Mid Dome Wilding Trees Charitable Trust.
We are responsible for controlling animal pests on land under our management.
Most of our pest control targets rabbits. We are part of the national Rabbit Coordination Group, led by Ministry for Primary Industries, which establishes best practice guidelines for this control work.