"Aquatic weeds, the silent invaders of our waterways, pose a particular biosecurity problem for New Zealand."
Biodiversity Strategy 2000
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The success of invasive water weeds in New Zealand is spectacular, at the cost of native biodiversity, hydro-electric power generation and recreational use of our waterways.
NIWA assesses the risks posed by potential aquatic weeds, both within New Zealand and at our borders, and advises on priority species for biosecurity management. The ways (pathways) and means (vectors) how weeds are spread are identified, as are ways to intercept them. The impacts of weeds and their management on the environment are quantified so that the ecological costs and benefits of biosecurity actions are clarified. A major goal is to expand the toolbox of solutions for the control and eradication of aquatic weeds and to best match solutions with specific weed situations.
Articles
Assess threats
Inventory introduced species
Assess competitiveness
- Gypsywort warning (PDF 210 KB)
- Weeds in waiting (PDF 474 KB)
Develop Risk Assessment Models
- Managing tomorrow’s weeds today – a risk assessment approach to aquatic weed management
- Weed risk assessment model
- Hornwort – our worst submerged weed
ID pathways & vectors
Advise surveillance strategies
Invasion outcomes
Measure impacts of invasive species
Measure impacts of control l
- Diquat Summary – use and safety
- Review of Diquat Reports of Relevance to Iwi Values in Lake Karapiro (PDF 160 KB)
- Effects of grass carp on the biota of a Waikato drain
ID risk of hybridisation
- Alien Hybrids (PDF 909 KB)
Managing weeds
Trial herbicides for NZ use
- Controlling hydrilla
- Control of hydrilla
- Manchurian wild rice: the alien invader can be stopped
- Managing marginal mayhem
- Hornwort Threatens Lowland Waterways
- Endothall trial for the control of Ceratophyllum demersum in the Wairarapa