What are dune lands and how do they form?
Dune lands are hilly areas of sand, found behind beaches.
Dunes are piles of sand, built up by the wind. They form inland from beaches that have plenty of sand. As the wind blows the sand, it builds into mounds around rocks and other small obstacles. The mounds grow, and become dunes.
In New Zealand, the wind comes mainly from the west, so dune lands have mostly built up on the west coast.
The native plants pīngao and spinifex, and introduced marram grass, grow on some dunes close to the sea.
Active dune lands
Some dune lands are active – they are not completely covered in plants, so wind can blow the sand, making the dunes move around.
The main dune lands
New Zealand’s biggest active dune lands are on the west coast – Northland, Auckland’s west coast, Waikato, Manawatū, Farewell Spit, the Fiordland coast, Southland and Stewart Island. There are some smaller dune lands on the east coast.
Increase in dunes
Fires lit by Māori may have cleared land for sand to move onto. Later, European settlers cleared grasses, shrubs and trees by the coast to make farms. The wind blew sand onto the cleared land, and the dunes moved further inland and covered larger areas.
From the 19th century, people worried about sand blowing around and covering the farmland. At Waikanae on the Kapiti coast, it even buried a church.
Stopping the spread of sand
Through the 20th century, many dune lands were planted with marram grass, which stabilised the sand. Large areas were turned into pine forests.
Loss of dune lands
New Zealand’s active dune lands have been reduced by about 70% since 1900. They have been turned into forests, housing areas and golf courses.
Restoring the dunes
In some areas, marram grass has taken over and become a weed, replacing native species like pīngao and spinifex, which once grew on the dunes. Today, some people are replanting these species and protecting the dune lands.