Coastal areas are dynamic environments, constantly reshaped by natural forces like tides, wind, and waves. In recent years, however, human activity has accelerated erosion and habitat degradation in these regions. Construction along coastlines, removal of vegetation, and rising sea levels have all contributed to the weakening of natural defences, leaving many coastal areas more exposed to erosion and flooding.
Without intervention, this can result in the loss of beaches, damage to infrastructure, and displacement of both human communities and native wildlife. Coastal restoration aims to reverse these trends by re-establishing natural ecosystems and reinforcing the coast’s ability to withstand environmental pressures. In doing so, it creates a buffer zone that not only protects property and lives but also supports biodiversity.
The Role of Native Plants in Dune Stabilisation
Sand dunes are one of the most important natural features in coastal defence. They act as a barrier between the ocean and inland areas, absorbing the impact of waves and wind while helping to prevent the inland migration of sand. Healthy dunes are key to protecting coastal settlements from the threat of erosion and storm surges, but without the right vegetation, dunes can be vulnerable to destabilisation and collapse.
This is where dune stabilisation comes in. By planting the right native species on the foredunes—the first line of dunes closest to the sea—we can help anchor the sand in place. The roots of these plants form an intricate web beneath the surface, binding the sand together and preventing it from being blown away by strong winds or washed away by waves.
Native plants have evolved to thrive in these harsh coastal environments. Their resilience, combined with their ability to stabilise the sand, makes them an invaluable part of any coastal restoration project. Two of the most important plants used in New Zealand’s dune stabilisation efforts are Spinifex (Spinifex sericeus) and Pingao (Ficinia spiralis).
What Native Plants to Use in fore-dune Restoration
Spinifex (Spinifex sericeus)
Commonly known as silvery sand grass, Spinifex is one of the most iconic dune plants found on New Zealand’s coasts. It is a hardy, low-growing grass that spreads through runners, allowing it to cover large areas of sand dunes quickly. Its long, silver-green leaves help to trap windblown sand, encouraging the natural growth of dunes.
The deep and sprawling root systems of Spinifex not only stabilise the dunes but also help to create a more structured dune landscape, allowing dunes to recover and grow after being eroded by storms or high tides. This plant is most commonly found on the foredunes, where its roots anchor the loose sand and prevent it from shifting.
Spinifex plays a crucial role in coastal ecosystems, offering protection for native wildlife by creating habitats for species such as the New Zealand dotterel and other shorebirds. Its presence contributes to the overall resilience of the coastal environment, helping both plants and animals survive in often hostile conditions.
Pingao (Ficinia spiralis)
Pingao, sometimes referred to as golden sand sedge, is another vital plant in coastal restoration. Recognisable by its bright orange-yellow hue, Pingao is culturally significant to Māori, who traditionally used its strong, flexible leaves in weaving. Today, Pingao is prized not just for its aesthetic and cultural value but also for its environmental role in dune stabilisation.
Like Spinifex, Pingao thrives on the foredunes and is highly effective at binding sand together. It grows in tufts and spreads out across the dunes, helping to stabilise and build the dune structure over time. The dense root systems of Pingao create a natural mesh that keeps sand in place, even during periods of high wind and storm activity.
While it is slower to establish compared to Spinifex, Pingao brings diversity to the foredune environment and adds to the overall stability of coastal dunes. By planting both Spinifex and Pingao, restoration projects can create a more robust and resilient dune system that can withstand environmental pressures for years to come.
The Growing Process: From Seed Collection to Protection
At Riverside Horticulture, we are proud to support coastal restoration projects by supplying native plants such as Spinifex (Spinifex sericeus) and Pingao (Ficinia spiralis). Our process ensures that these plants thrive in their new environments, contributing to the stabilisation of dunes and the restoration of native ecosystems.
Our process typically begins with eco-sourcing seeds from local coastal areas, ensuring genetic diversity and suitability for the specific region. However, this is not always essential, as both species show minimal if any differences when grown from non-eco-sourced seed. Once collected, the seeds are isolated and carefully cleaned to remove any duff or foreign matter, preparing them for sowing. We sow the seeds late in the year using our specialised seedling line, which allows us to monitor and nurture their growth throughout the summer months.
During this period, we provide dedicated care to ensure the plants are established well. Once the seedlings are ready, we often re-pot them into EnviroPots, a biodegradable pot designed by our team that means you can plant the plants directly into the dune with less plastic used and less irritation to the roots.
The plants continue to grow for a few more months before they are dispatched to our clients, ready for coastal planting. These plants are primarily grown on contract to meet the specific needs of restoration projects, ensuring high-quality results tailored to the environment and the client's needs.
Challenges and Opportunities in Coastal Restoration
While coastal restoration and dune stabilisation offer powerful tools for protecting seaside communities, these projects are not without their challenges. One of the main issues is the ongoing threat of climate change, which is causing rising sea levels and increasing the frequency of extreme weather events. This means that the work done in coastal restoration must be adaptable and long-term, as conditions are likely to change over time.
Another challenge is the need for collaboration. Successful coastal restoration requires the combined efforts of local authorities, environmental groups, iwi, and community volunteers. Without coordinated action, it’s difficult to implement the large-scale restoration efforts needed to make a lasting impact. Fortunately, awareness of the importance of coastal protection is growing, and more people are getting involved in restoration projects across the country.
For Riverside Horticulture, being part of these projects means more than just supplying plants. It’s about contributing to the long-term health of New Zealand’s coastlines and ensuring that future generations can enjoy these environments, just as we do today.
As we face the ongoing challenges posed by coastal erosion, rising sea levels, and climate change, the importance of coastal restoration has never been clearer. Native planting and dune stabilisation offer a natural, sustainable way to protect our beaches and communities. By planting resilient native species like Spinifex and Pingao, we can help restore and stabilise New Zealand’s coastlines, creating a buffer that safeguards both human settlements and native ecosystems.
At Riverside Horticulture, we are proud to play our part in these efforts. By working with local communities and providing the plants needed for successful restoration, we are helping to build a future where our coastlines are better equipped to withstand the challenges ahead.