Dunes are under pressure from human activities. We need to protect dunes to preserve their natural character and because they provide erosion and flood protection.
On this page:
Why are dunes important?
Dunes are narrow but important areas of sand that lie between the sea and the land. Dunes and their native plant communities are part of the natural character of our distinctive New Zealand coastline.
Dunes protect properties against coastal erosion and flooding from waves. They:
- provide a physical barrier against storm waves, reducing the risk of flooding for nearby properties
- work as a dynamic buffer, and are eroded and then built up again as part of natural physical processes.
However, when these natural processes are interfered with, our coastline becomes more exposed to Coastal Hazards such as storms and flooding. There are two types of coastal erosion:
- Short-term erosion - This can be caused by storms or climate cycles without causing a permanent change in the position of the shoreline. While the area usually recovers, a full erosion and recovery cycle can take several decades.
- Long-term erosion - This is when there is a permanent change to the position of the shoreline, for example, through erosion caused by sea-level rise.
Dunes contain information about past climate, the build up of beach sediments and vegetation cover over the last 6,000 years. But human damage to dunes has destroyed much of this information. Valuable cultural sites (including shell middens, remains of living areas and urupa) have also been lost.
Dunes are adapted to natural coastal processes, but are fragile and easily damaged by human activities.
Our region’s dunes
The Region’s dunes have been greatly affected by human activities since the early European settlement of coastal areas.
The removal of dune plants has led to widespread wind erosion, especially of the most seaward dunes. This led to damage and the loss of:
- the protective buffer dunes provide against erosion and flooding
- beach sand reserves
- natural character.
Sand has also moved inland, burying land (particularly on the West Coast).
A recent survey of Waikato coastal dunes showed that about 70 percent of the total dune area has been modified for coastal subdivisions, forestry, agriculture and sand mining over the last 55 years.
Although pressures from mining and agriculture have decreased in recent decades, pressures from coastal development and structures are increasing.
Dune plants and animals
Sand binding plants
Sand-binding plants play an important role in the formation, development and maintenance of dunes. If dune plants are destroyed, eventually the dunes themselves can be lost, leading to severe damage to the beach and risk to coastal properties.
Our dunes were originally covered by:
- native sand grasses on the seaward face of the foredune
- larger and more diverse shrubs and trees inland.
Today, no intact examples of this natural plant sequence remain in the Waikato Region. The loss of native coastal trees and shrubs is particularly obvious.
For example, the beaches of the eastern Coromandel Peninsula largely lack native trees and shrubs, though isolated pohutakawa trees and other plants remain. Early regeneration of native trees and shrubs is evident at some sites (such as Whiritoa Beach).
There are two main native sand-binding plants:
- pingao (golden sand sedge)
- spinifex (silvery sand grass).
These plants are well adapted to the dynamic conditions on the beach and send out runners which bind the sand. Pingao is a golden colour and is an important weaving material. It is also a threatened plant, and has to compete with introduced plants and survive grazing by rabbits.
On modified dunes, native sand-binding grasses have often been lost or replaced. In some areas, the native plants have been replaced by managed grassland. In other places, marram grass has been introduced to stabilise the dunes. Marram grass changes the way dunes build up and their shape, and doesn’t provide suitable nesting habitat for some coastal birds.
Dune animals
The dunes provide homes and food for small animals including:
- insects
- spiders
- butterflies and moths
- lizards.
The animals in turn provide food for coastal birds. Find out about the coastal animals that live on our beaches and dunes.
Taking care of dunes and beaches
Environment Waikato has been involved in dune vegetation trials to restore native coastal plants. We have also helped to establish the Coastal Dune Vegetation Network. The Network promotes research and helps people share information about restoring native coastal plants.
Protect our dunes and beaches and the plants and animals that live there, by following the Dune Care Code.
Beachcare groups encourage dune care among coastal communities and protect and enhance the natural character of beaches and dunes. In our Region, Beachcare groups have:
- planted around 200,000 coastal plants since 1993
- removed plant pests
- installed beach access ways, signs and other measures to help manage human pressures.
Find out more about Beachcare groups.
Want to know more?
See our publications pages to order a copy of: