Beach areas just east and west of Ōpōtiki Harbour could one day become a go-to destination, showcasing how to restore and protect Aotearoa’s coastal ecology.

That’s the hope of environmentalists working to offset the latest challenges of rising seas with one of the oldest strategies. They are working to restore the same sand dunes which have defended the Kiwi coastline for hundreds of thousands of years.

Nature’s own barrier to rising seas –sand dunes – presents a soft edge which over the long term will protect roads, buildings and farms more effectively than the strongest made-made sea wall.

Reason: While concrete will eventually be undermined or cause further erosion due to tidal action and storms, sand dunes constantly renew themselves.

The seasonal ebb-and-flow of sand transported out beyond the breakers and back up the beach is one part of this equation. However, just as important to the dunes’ ability to heal are native plants which trap sand so that – notwithstanding seasonal gains and losses – over the long term there will be a net gain in dune width.

With all this in mind, Whakatōhea has collaborated with others in the present restoration efforts on both sides of the Waioweka River at Pakihikura.

The work was mandated by consent requirements for the construction of the harbour entrance, whose twin sea walls were officially opened last year.

The work caused disturbance to the environment on both sides, in particular, to the western side where the old river mouth had to be filled in. New sand dunes had to be constructed there to repair the damage and protect the new structures.

Those involved in the project have quietly been repairing the damage from human development, which has spread out across the back dune system. They fenced off the front of the dunes to protect them from spinning wheels that destabilise sand. They have also been eliminating the grazing pests and weeds that destroy native plant cover.

Already the restoration work is bearing fruit, as evidenced by consolidating land and returning wildlife.

The harbour project has halted the westward migration of the river mouth, providing increased protection for urupa sites and the second stage of the Waiotahe Drifts Subdivision.

The restoration work carried out over the past two years is one of the largest such projects attempted in New Zealand. It is led by Jim Dahm, a coastal processes expert, who works with the help of Tim Senior, a local ecologist. They have forged a successful partnership with Whakatōhea, whose Tiaki Taiao team is tackling the groundwork.

Work began almost two years ago with planting an area on the eastern side where rock for the groynes construction had previously been stockpiled. Initially, coastal forest species planted there struggled in the poor ground, but these will take off as their root depth increases over time. A second area will be planted with similar species once the remaining rock stockpile is removed.

Closer to the shore, new dunes have been constructed, these comprising a small length on the eastern side and 1.2km on the western side.

Tiaki Taiao team members began planting these areas out late last winter, the idea being to replicate what would naturally grow on a dune. They have been kept busy eliminating the rabbits and hares which defiantly graze the newly planted natives. They also dig out invasive weeds, which if left unchecked would eventually choke the native vegetation.

The gently sloping fore dune, which faces the sea, has been planted with a mix of kowhangatara (spinifex) and pingao. These plants are now well established, sending out runners and doing their job of trapping sand blown off the beach.

The steeper back dunes were planted with a mix of wiwi and pohuehue. More of these will be planted this winter.

The Taiki Taio team has so far planted about 30,000 plants on the new dunes.

Owing to the continuing dredging work, the dune construction was not quite finished last winter. It is expected to be completed before the end of winter, with newly created dunes then ready for planting several thousand more plants.

The western groyne access road has been fenced off, with a temporary fence erected just above the high tide mark. On the landward side of the fence, planting of coastal forest species has begun with many more plants planned to go in over winter.

Several pairs of rare New Zealand dotterels found the wide expanse of beach now created on the western side of the harbour much to their liking.

“Three pairs nested and successfully fledged five chicks between them, which is a fantastic addition to the local population. Trapping and baiting rats and stoats to protect the birds has been another job for the team,” Mr Senior said.

“The team has erected plenty of signs all around the sites requesting people to keep out of the fenced areas, control their dogs and keep their vehicles out. It has been very gratifying to see that, with only a couple of exceptions, people are sticking to the rules. We’d all like to thank the locals and visitors for doing so.

“This has allowed the plants to grow and the dotterels to nest without disturbance.”

Weekly monitoring of all the restoration areas has been a regular task for the team. Their observations have shown the need for periodic repairing of temporary fences, weed control and further rabbit and hare shooting.

“Rabbits and hares have been quite a headache for the team as they are very fond of pingao in particular. However, we’re now all looking forward to the next big planting effort in a couple of months with many thousands more plants to go in.”

Biggest project ever done

Members of the Ōpōtiki community have done dune planting for a long time, but the current harbour development restoration project is the largest ever attempted, Whakatōhea Toi Ora environmental manager Logan Bertram says.

“It’s really great project because we know it’s all for the benefit of future generations. We are a coastal community; a lot of us were involved in similar work planting the sand dunes when we were kids, but this is next level.”

Part of resource consent conditions for the harbour development, the project coincided with the tribe’s environmental values, in particular by preserving areas of high cultural significance.

“The success of the birds’ breeding speaks volumes about the success of the project thus far. Equally important to us is that it has limited access to some of our culturally sensitive areas at Tawhitinui, also known at Huntress Creek.”

Tawhitinui had passed from Department of Conservation to Whakatōhea ownership, allowing the iwi to reclaim land which was culturally important. Since being fenced off it had been regenerating in native vegetation

“This is an historic burial ground but over the previous 20 years, it has been utilised as a four-wheel-drive park. These vehicles are now excluded from the area.

“We have been happy to take a collaborative approach toward the restoration in the area. Most of the planting is being done by the restoration team, but we also try to get as much of the community out as possible. We have volunteers checking traps all the way along the dune area and we are trying to hold some community days for planting.

“These began last year, but it was more difficult then because the site was an active construction area. This year, as conditions now suit it better, there will be more voluntary labour in use.

“There were regulatory hoops to jump through compliance wise to get this area established, but the birds moving in shows we are on the right track.

“We’re basically one year into a three-year restoration project, but I think it is going to end up being a little bit longer than that.

“Whakatōhea has been involved from the planning phase onward, taking responsibility for implementation of the ecology team’s goals.

“As a continuation of work, which had been under way for years on coastal areas, we’re planting, doing animal and weed control and monitoring.

“The challenge now is to defend our plants from hares and rabbits – we’ve tried many a cunning method to get on top of them, but it’s proving rather difficult, coming down to the need for many hours of pest control.”