Will didymo remain in the South Island or will it move to the North Island?

A didymo likely environments model by NIWA shows that most of the highly suitable New Zealand rivers for the establishment of didymo are in the South Island. However, parts of the North Island are also suitable for didymo establishment and growth, particular in the mountain regions and the central plateau. There is no evidence yet of any spread to the North Island, but rivers could be affected. For more information about likely environments for didymo, view the maps on our website. Environments suitable for the establishment of didymo include cool water, stable riverbed and waterflows, high light availability, moderate flow velocity, and pH neutral or slightly alkaline.

Didymo - Where is it?