Explore the importance of sand dunes and the impact of losing them. Find out about the largest coastal plant protection programme in the southern hemisphere.

This teaching resource explores the importance of sand dunes for the animals and plants that live in and around them. Find out about the impact of introduced species on our coastline and investigate the reasons for their introduction.

The focus is on pīngao or pīkao - the golden sand sedge and exploring the largest coastal plant protection programme in the southern hemisphere at Mason Bay in Stewart Island.

It links to websites and learning tools which provide practical activities to develop your students' knowledge and skills.

About the resource

Learning levels:

  • Primary
  • Secondary 


  • Native plants
  • Marine and coastal

Curriculum learning areas:

  • Science (Living world)
  • Social science
  • Education for sustainability
  • Technology

Achievement objectives:

  • Students will explain how living things are suited to their particular habitat and how they respond to environmental changes both natural and human induced.
  • Students will understand how people participate individually and collectively in response to community challenges.

Learning outcomes:

  • Students will draw a diagram that shows how sand hills are formed.
  • Students will devise a fact box showing why and how a particular sand dune species has adapted to the sand dune environment.
  • Students will construct a filter and use it to explain how a sand dune environment acts as a filter for ground and rain water.
  • Students will use supplied information to compare marram grass to pingao and draw T charts to show the impacts of both.
  • Students will take part in a debate and show they understand why people make decisions that will impact on the environment.   

View the resource

DOC and TVNZ collaborated to create this resource NZ Geography: Our own gold coast which was written by DOC ranger Mike Tapp. 

Contents of resource:

What are sand dunes and how are they formed?

1. Show some sand dune photos and ask how they are formed. Here are some sand dune photos on the Nature's Pic website.

  • Provide long strips of paper and in pairs, students can draw their ideas as a diagram.
  • Provide the handy hints contained in What are sand dunes? (PDF, 42K) worksheet on the TVNZ website.
  • Supply another strip of paper for students to modify their ideas on.

2. As a class, decide which examples best show how sand dunes are formed and then enlarge the diagram in mural form across the wall of the classroom.

What lives in and around the dunes?

3. Share this little gem as an introduction to the plants and animals that live among the sand hills and on the beach.

If a sandhopper is picked up and released in the sand dunes, it hops back across the beach towards the sea. If released a kilometre inland, it will still hop back to its beach.

Catch a sandhopper on a Canterbury beach, on the east coast, and release it on a West Coast beach and it will try to do the Coast to Coast! It will hop back towards the east coast.

Sand dunes are home to a number of unique native plant communities, invertebrates, lizards and birds which exist nowhere else. Introduced species and human activity have changed the sand dune environment and have threatened plants like the native pīngao, spiders like the katipo and other insects and birds.

Get your students to research a beach or dune critter below and organise a fact box with a picture and some fascinating sandhopper-like information that shows how that particular species is adapted for the sand dune environment. They can place their fact boxes in the best habitat on the mural.

Invertebrates include:

  • kelp flies and midges
  • the copper butterfly or the notoreas moth
  • wasps and sand-hoppers
  • the sand scarab and tiger beetle
  • the mighty native seashore earwig
  • spiders like the nursery web spider, the jumping spider and the now rare katipo

Lizards include:

  • shore skinks
  • Taranaki gold striped gecko
  • common gecko

Seabirds include:

  • New Zealand dotterel
  • banded dotterel
  • pipi
  • Caspian tern
  • white fronted tern
  • variable oyster catcher
  • gulls

Plants include:

  • pīngao
  • spinifex
  • sand coprosma
  • sand daphne
  • pimelia

Sand dunes as filters

4. Sand dunes enhance and maintain coastal water quality by acting as filters for rain water and ground water. Investigate how.

As a class discuss how fresh water gets to the sea and the ways it may become polluted along the way. Find out about fresh water on the Ministry for the Environment website.

Give each group a one or two litre plastic bottle, some stones, cotton wool and some sand. Supply snips and a container for mixing up some grubby water and ask them to make something that will clean up the dirty water.

Answer: Cut the top of the bottle off just below the neck. Sit this part upside down in the bottle so it forms a funnel. Add the cotton wool, sand and then stones. Trickle the grubby water into the stones and it should emerge clear.

Relate this information back to the sand dune diagram/mural and decide how that ground water is getting into the dune area and where it is filtered. Decide if the impact of development and pollution can be lessened by coastal dune landscapes and dune wetlands and add to the diagram/mural to show how.

Protecting the land

5. Coastal dunes act as a buffer against eroding wave action and protect the land behind. The dune vegetation also traps wind blown sand and prevents it being blown inland.

The dune environment is dynamic and always changing. It's a natural and healthy part of this ecosystem and helps maintain biodiversity but change is difficult for humans to accept.

To cater for coastal development we've tried to stabilise the dunes with introduced species like marram grass and lupin. It's altered the dynamics of the dunes and upset the coastal ecosystem.

Sandbinders lets the students compare the introduced marram to the endemic pīngao. Using the sandbinders information sheet (PDF, 46K) on the TVNZ website as a guide students can organise this information by generating two T charts. One will show the impact of marram grass and the other the impact of planting pīngao.

e.g. The impact of marram grass

Plus Minus Interesting

Discuss the t charts and then watch the Meet the Locals episode Pīngao to see who's involved and how people can replant to help sand dune ecosystms recover.

Going to war

6. Mason Bay, on the west coast of Stewart Island in Rakiura National Park, has one of New Zealand's largest remaining unmodified dune systems with a 19 kilometre long beach and amazing beauty and wildlife that draws visitors from around the world.

This innovative restoration project, will see marram grass completely removed within twenty years and replaced with the orange swaths of native sand-binding pïngao. It's the biggest dune protection project in the Southern Hemisphere.

Discuss in class why species have been introduced to New Zealand and how they have changed the environment. For example:

  • Possums, brought in for the fur trade are eating our forests;
  • Stoats, brought in to kill the rabbits are killing bird life instead;
  • Gorse, brought in so the yellow flowers would remind settlers of home, grows bigger and better and in more places.

Talk about why these introduced species do so well here. Our trees for example have never needed a defence system. In Australia several species are bitter and the leaves are unpalatable. The possums there, leave them alone. Many of our birds were and are ground dwelling and easy pickings for stoats. Our soil is more fertile and the mild climate makes for ideal weed growing conditions.

Go back in time with the Meet the Locals episode Mason Bay Homestead to try build an understanding of why people changed the land. The farmers of Mason Bay were happy to see marram grass growing on the sandhills but why?

Look at the Going to war at Mason Bay worksheet (PDF, 48K) on the TVNZ website to see the impacts of the planting.

Then have a mini debate between the farmers of the 1930s and a team of scientists. The topic:Planting marram grass will benefit all Stewart Islanders.

Now watch the Meet the Locals episode Dune restoration.

Active involvement

7. Discuss examples of coastline change in your area and decide whether it was once like Mason Bay, or the dune mural on the wall. Contact your local council and see if there are areas that are being restored with new plantings. You may be able to help with a planting day.


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