Tāne's Eyebrows

The wild, windswept sand dunes of Aotearoa must be among the planet's harshest habitats for plant survival.

Below: A stand of fiery orange/red pīngao replanted in front of the invasive introduced marram grass in the background, which has virtually smothered the native pīngao from its natural habitat on the loose sand dunes of our coastline.

Frequent gales, reinforced with sand and salt spray, sweep all before it, sand-blasting and burying anything and everything under a gritty blanket in this constant battlefield between sea and shore.

Legend has it that Tāne Mahuta (God of the Forest) plucked out his eyebrows and gave them to Tangaroa (God of the Sea) as a peace offering to end the warring between them, but Tangaroa cast them on to the shore where they grew as pīngao, one of few native plants capable of surviving in such a hostile environment.

The coastal battle rages on between Tāne and Tangaroa, but it is not hard to imagine pīngao as Tāne's eyebrows, blown flat on the crest of a sand dune by an on-shore gale.

Pīngao, also known as pīkao in the south or golden sand sedge to botanists, is one of three major endemic native sandbinding sedges. The others are kōwhangatara (spinifex) and hinerepe (sand tussock).

Pīngao is superbly adapted to life in a transient environment. The more exposed, bare and unstable the sand, the better pīngao likes it.

This tough species needs the continuous movement of sand around its leaves, base and roots to survive. It sends out rope-like rhizomes from the parent plants that trap sand, binding and stabilising the dunes.

Its extensive root system captures what little water is available and helps sustain the plant through hot, dry conditions.

Sedges are similar to grasses and tussocks in appearance but can be distinguished by the triangular shape (in crosssection) of their leaves. The foliage of pīngao is a brilliant green, which turns golden yellow or fiery orange at the tips.

The leaves are stiff, curled and rough to touch.

It sets seed in a spiral pattern (which explains its botanical name, Desmoschoenus spiralis). Its main means of reproduction is by wind dispersal of its spiky seeds, which race along the sand – giving rise to another of its nicknames, tumbleweed.

So if this plant is so superbly adapted for survival in such hostile conditions, why is it listed as an endangered species?

Pīngao was once widespread from Northland to Rakiura and the Chatham Islands. Now it is found growing naturally only in a few remnant populations or where community and iwi groups have successfully re-established it in scattered pockets around the country.

Like many native plant species, pīngao's demise is blamed on human activity – fires, vehicles, grazing, trampling by humans and livestock and browsing by introduced pests like rabbits, possums and hares.

In his book A Pākehā's Recollections, Murray Gladstone Thomson recalls collecting frostfish on Otago beaches with friends around the 1880s and setting fire to the native grasses on the sand dunes to keep warm or perhaps just to relieve the boredom of a sparse catch.

Ironically, years later Thomson was a strong advocate of planting introduced marram grasses on the same Otago beaches to try to control coastal dune erosion.

The highly competitive marram grasses and tree lupin were hailed as the solution to coastal erosion. Planting continued until the 1980s.

In fact, these introduced species were so successful they smothered pīngao, destroying the windblown sand dunes pīngao needed to survive.

Today, the Department of Conservation identifies pīngao as a "keystone" species, one whose colonising ability in a fluid landscape encourages biodiversity and creates a suitable habitat for other native coastal plants.

Culturally, pīngao is one of Ngāi Tahu's taonga species that is highly prized for its naturally vibrant yellow / orange colours. It provides stark contrast to the pale tones of harakeke and kiekie when dried for decorative use in weaving.

It was commonly used in tukutuku panels to decorate the walls of wharenui.

It was also used for fine plaited kete (bags), whāriki (mats), pōtae (hats), pare (headbands), tātua (belts) and pōkeka (rain capes).

Traditionally, the method of preparing the leaves was to soften them in water. Then they were carefully scraped with a shell as required to prevent them curling. The leaves dry to a natural yellow/orange hue.

In his ethnobotanical research Traditional Lifeways of Southern Māori, James Herries Beattie records that "pōkeka made of flax, tussock and pīngao were regarded as thoroughly waterproof".

He also notes the tough leaf of pīngao was used to weave poho taupā (chest protectors) to protect warriors from spear thrusts and blows during battle, and as tāhau taupā (shin guards).

Other sources suggest the young tender shoots of pīngao were "sweet and palatable" when steamed and eaten. It probably helped if the diner had an appetite honed by a few days of bush tucker, but it seems the plant's only medicinal value was for ceremonial purposes.

Historically, Māori harvested the leaves of the plant in autumn, when a side shoot was cut from the parent and planted alongside it to ensure a sustainable harvest.

In recent years, the Forest Research Institute confirmed this clipping technique was the most sustainable method of three harvest methods tested, ensuring a sustainable supply of fibre for cultural use from a vulnerable species.

In Otago, a Pīngao Recovery Group has been active for years, working with the Department of Conservation, the Dunedin City Council, Otago Regional Council, Te Rūnanga o Ngāi Tahu and other community groups to replant pīngao on beaches from Waikouaiti south to Moturata Island at Taieri Mouth.

In terms of pīngao's survival, perhaps it is fortunate this remarkable plant is highly valued by Māori for its cultural significance as well as its conservation value as a stabilising influence on our coastal sand dunes.