Riparian trees strongly modify stream habitat – most notably by shading. Riparian shading keeps stream water cool and inhibits the growth of nuisance aquatic algae and plants (Figure 1). Most of New Zealand’s approximately 400,000 km of stream length was originally heavily shaded by native riparian forest but clearing trees for agriculture and other uses has exposed many streams to direct solar heating.
A new programme at NIWA will focus on finding ways to protect our freshwater species now and in the future.
The plight of some coastal lakes in Canterbury is well-known. Many were once abundant mahinga kai site for local Māori, some are now the most polluted waterbodies in the country.