Braided Rivers and Invasive Weeds

4 April 2023

The Rakitata | Rangitata River is one of the key braided rivers of the Canterbury Plains; running down from the Southern Alps and entering the Pacific Ocean just north of Timaru.

The Upper Rakitata | Rangitata River catchment is an ecologically significant area, with extensive landscape and indigenous biodiversity values. The braided river system is important for providing critical habitat for native species including the wrybill, black-fronted tern, black-billed gulls, banded dotterel, and the South Island pied oystercatcher.

Currently, the upper Rakitata is a comparatively pristine environment, with relatively low abundance of invasive pest weeds. However, invasive weeds are notorious dispersers and without effective management will take over this environment.

Pest weeds displace and outcompete native plant species, provide habitat for predators such as rats, hedgehogs, and stoats that prey on river bids, remove nesting sites for birds, and change the river morphology.

Long-term strategic direction for monitoring and controlling invasive weed species, such as broom, gorse, and Russell lupin, is required to limit the spread and reduce weed abundance within the upper reaches of the catchment.

For further information please contact Pete Caldwell