Human interactions with the fragile dune can enhance erosion processes.
It is important that people look after dunes as they are the home to endangered
shorebird species such as the New Zealand Dotterel that lay their eggs there.
For example this part of Muriwai is a designated Road. 4-wheel drives and
dune buggies are daily driven on the beach
making tyre tracks that can enhance erosion.
In many parts of the coast vehicles have done considerable damage.
Horse riding is also a popular activity
that has the potential to erode the beach.
Councils fence off walking tracks to prevent people walking on the dunes.
However erosion can happen on the tracks and be enhanced by wind funneling.
Vegetation is essential for stabilizing dunes.
The vegetation traps the sand and holds it in place.
If vegetation cover gets removed wind will remove the sand leaving a blowout.
If natural vegetation cover is removed dunes can advance inland.
Originally the coastal land at Muriwai was covered in native vegetation.
But by the 1870s sheep and cattle grazing began, causing problems.
Damage to vegetation by grazing animals caused the dunes to migrate inland,
with some dunes being reported to have reached as high as 90 meters,
like these ones at Te Paki in Northland.
In 1880, 46,000 hectares of land was covered by dunes.
By 1909 this area had grown to 120,000 hectares.
In 1903 Parliament (NZ) passed the Sand Drift Act.
But little was done until the 1920s and 1930s when there were attempts to stabilize the sand
through the planting of exotic marram grass which is native to France.
In 1932 the planting of pine seedlings began creating Woodhill Forest.
This was successful at turning the tide of the encroachment by the sand.
Since then attempts to save the frontal dunes have involved the planting of native species.
Today you can see many plant species growing in the dunes at Muriwai.
Ranging from native species such as spinifex,
Pingao grass,
Bunny tail grass
and the Karo tree,
as well as exotics like ice plant.
I hope watching this documentary has enhanced your understanding of coastal
processes and its relevance to people.
Thank you for watching.