What is a riparion margin/zone? 

Basically a riparian margin is a strip of land adjacent to the waterways. A riparian zone includes the riparian margin and the waterway.

Management of the riparian zone has a direct influence on -

1. Stream bank erosion and other flood flow effects
2. Entry of unwanted nutrients e.g. Nitrates
3. The "stream quality" i.e. weed infestation, water clarity, fish-life and general aesthetic values

Good management means -

1. Retiring/fencing the margins off to "unwanted" activity i.e. grazing
2. Establishment of the appropriate vegetation
3. Maintenance/monitoring
4.  

What is the appropriate vegetation?

Plants that are suitable include primary colonisers such as cabbage trees, coprosmas, flaxes, pittosporums, native toetoe, lacebarks and kowhai. Native grasses such as Carex secta, Carex virgata and Carex solandri provide good vegetation at the stream-edge.