Riparian planting saving our streams
The classic Kiwi holiday often involves swimming in streams, a spot of fishing and enjoying the beautiful outlook of streams shaded by native plants and seemingly endless green landscapes. But our streams, as we know them, are at threat, so it’s time to get planting…
Before humans arrived in New Zealand, a majority of our lowland waterways were heavily shaded by forests. Streams and rivers were cool, slowly meandering, stony-bottomed and supported an abundance of life. Great for drinking from, harvesting from and swimming in.
Sadly that is not the case now… 44% of all monitored lakes in New Zealand are polluted, and 62% of our lowland rivers have more pathogens than are safe to swim in. The stats are even worse for lowland lakes in farmland – 84% are so polluted they become eutrophic. In fact many of our waterways are so bad that even our native fish have disappeared!
Over the last several hundred years, a large proportion of lowland forest has been cleared, resulting in loss of vegetation and environment modification. This has impacted streams in the following ways;
- Loss of shade to the water.
- Loss of structural habitat for aquatic fish and invertebrates.
- Stream bank erosion.
And it doesn’t stop there. The silt and contaminants course straight to our beaches and harbours, impacting the marine environment – especially shellfish, fish stocks and seaweeds. So what can we do to help?
Riparian restoration (replanting the banks of streams, rivers, lakes and wetlands) is a simple way to improve water quality and enhance freshwater biodiversity. Local councils, farmers and community groups around New Zealand have already made a start replanting rural and urban waterways.
Riparian planting has the following benefits:
- Reduce erosion and sedimentation by trapping sediment before it enters the stream.
- Filters phosphorus and industrial contaminants before they enter the stream,
- Buffer the impacts of floods by acting as sponges to hold excess water and keep soil in place.
- Provide cool shaded habitat and food for native species.
- Sequester carbon.
The health of our waterways affects all New Zealanders, so we all need to be part of the solution. Get planting this New Year and support the work of the Million Metres Stream Project to ensure Aotearoa’s waterways remain clean and green.
For more information please visit www.millionmetres.org.nz
20-Feb-2015
In the Garden
