Pests and weeds in Waikato
In Waikato we work on a number of sites including Lake Karapiro, which was artificially formed in the 1940s as part of a hydroelectricity scheme. It is widely used for recreational activities including rowing, kayaking, fishing, and camping. These activities are threatened by aquatic weeds including hornwort, which can overtake waterways hampering recreational activities.
We also have responsibilities in relation to the Waikato River and lands in the Wairakei geothermal area. Both the banks of the river and the geothermal region have been invaded by terrestrial weeds including wilding conifers, gorse and broom which smother native plants that are specially adapted to the geothermal environment.
Tackling the problem
We are targeting control work in Lake Karapiro, one of New Zealand’s premiere rowing destinations.
Active control of hornwort and other aquatic invasive weeds in Lake Karapiro is critical to ensuring it can continue to be used. Left unchecked these weeds will smother the lake and inhibit rowing and other uses. There is also a risk that without control rowers travelling to the South Island will spread the aggressive hornwort weed, which is currently absent from South Island waterways.
We carry out boat and aerial control of aquatic weeds on Lake Karapiro and in the rivers leading into it Lake Karapiro to reduce the risk of weeds such as lagarosiphon spreading into the lake
Weed work in geothermal areas is highly technical due to challenges created by steam and bubbling mud. We are working with Waikato Regional Council and other partners to address and restore these areas.
Working with others
LINZ is a part of the Lake Karapiro Aquatic Weed Management Group, which also includes Waikato Regional Council, Waipa District Council, Ngati Koroki Kahukura and Mercury Energy
How you can help
All lake and river users also have a role to play in stopping the spread of water weeds. If you’re moving between waterways, you must clean all your gear using the 'Check, Clean, Dry' method. This stops plant fragments moving between waterways, which can be all it takes for a new infestation to begin.