Aquatic macrophyte management in New Zealand

Summary

Aquatic weed problems have been caused by plants introduced to New Zealand since organised European settlement in 1840.

Native communities, whilst rich in tall growing emergents, were impoverished in species numbers and other aquatic life forms.

Post human settlement modified aquatic habitats and post European settlement evidenced a spectacular invasion success of introduced species whose dispersal barriers to New Zealand were bridged by man.

Adventive free-floating weed problems have been avoided by noxious plant legislation and sprawling emergent weeds have been most troublesome in agricultural drainage systems.

Introduced submerged weeds have displaced or stressed native submerged communities, and many submerged macrophyte habitats have been stressed or changed by eutrophication or habitat disruption.

Herbicide treatment and mechanical removal of weeds have dominated aquatic plant management programmes.