Our sand dunes are valuable

Protect the dunes and they'll protect us

Spirits Bay.

Why protect our sand dunes?

Beaches and sand dunes are the narrow but precious bands of sand that lie between the land and the sea.

Sand dunes are natural habitats for many native species and, in their natural state, they protect land and property from erosion, storms, cyclones and tsunamis.

But many of our dunes are under threat, which creates instability, increased erosion and loss of native plant and animal life.

Large areas of Northland's coastal dunes have been modified for residential development and farmland. This has led to changes in dune stability, often resulting in vegetation loss and wind erosion.

Our dunes are also under pressure as the population grows. Wheels, feet and animals destroy dune vegetation. Even small losses in dune vegetation can lead to significant wind erosion.

The good news is that we can all play a part in caring for and protecting Northland's valuable dunes.

Vehicle driving over sand dunes.Driving or riding on dunes destroys plants and causes erosion.

How do sand dunes work?

Sand dunes are always changing as they erode and build-up in cycles. Vegetation plays a critical role in the natural cycles of dune erosion and recovery that occurs on beaches.

Settled weather

Sand builds up on the beach and dunes.

Settled weather, dune diagram.

During a storm

Waves erode the beach and dune, leaving a steep dune face. A bar is created as eroded sand settles offshore in the surf zone.

During a storm, dune diagram.

After the storm

Sand is transported back onshore and rebuilds the beach. Dune vegetation grows seaward down the eroded dune face.

After the storm, dune diagram.

Dune recovery

Sand blown landward from the beach is trapped by dune vegetation, gradually repairing and rebuilding the dune.

Dune recovery diagram.

Thanks to the Dune Restoration Trust of New Zealand for allowing us to reproduce some of its information. www.dunestrust.org.nz