Pīkao or pīngao, the golden sand sedge (Ficinia), is a native sand-binding sedge that plays an important role in New Zealand's dune ecosystems.
It has stiff, curled leaves that can be a brilliant green - especially when young - golden yellow or, on more mature plants, a fiery orange. In spring it produces flower heads up to 30 cm long, with dark brown flowers that spiral around the stem.
Stunning pīkao stands would once have been found on almost every sandy beach, from Northland to Rakiura (Stewart Island) and the Chatham Islands. Today only a few remnant populations remain.
Pīkao is found only in New Zealand and is one of our major native dune builders, stabilising sandy areas by trapping wind-blown sand. It does this between its leaves, around the plant's base and with the long rope-like rhizomes or runners it sends out.
By allowing or encouraging sand dunes to form, pīkao creates an environment in which other native coastal species can establish and flourish. Naturally occurring pīkao is a good indicator of biodiversity in a coastal environment.
It's thought that the regional differences in pīkao's morphology relate to frost tolerance. In the north the plant has sprawling rhizomes, but heavy frost will knock these back. In the south, therefore, pīkao is hardier; more compact and erect, has fewer rhizomes and withstands cold winters.
Traditional uses
Pīkao is a taoka or treasure; one of four main native fibres used by iwi for weaving and sought after because the dried leaves are a brilliant yellow. It's used extensively on tukutuku panels in the wharenui, as well as for making kete (bags), pōtae (hats) and whāriki (mats) and many other functional or decorative items. Southern Māori once wore woven pīkao chest protectors in battle and when the young shoots were steamed, it was used as a food.
Threats
Pīkao's disappearance from the coastal environment can be attributed to a wide range of influences and events.
The greatest threat to pīkao is considered to be marram grass which was introduced at the turn of the 20th century to stabilise areas that had been protected by pīkao but had been burnt from around the 1880s onwards. Marram's nitrogen fixing companion plant, the yellow tree lupin, arrived around the same time. Together they literally smother the smaller and far less competitive pīkao.
Because of its invasive qualities, marram has been used a lot on reclamation and development projects, often at the expense of pīkao remnants. One of the reasons that marram is so competitive is that it turns more mobile dune habitats (pīkao's preference) into a much more stable environment. As a result pīkao succumbs to the invader's pressure.
Burning by early settlers was a major reason for pīkao's decline along with land development for agriculture and forestry. Many dune areas that were once covered in pīkao are now stabilised by pinus radiata plantations. Several plantations along the Horowhenua-Wanganui coastline are good examples.
Grazing is also a major problem. Originally the damage on coastal properties was done by sheep and cattle, but rabbits and possums have also developed a taste for pīkao. This can be a major problem in areas with high rabbit numbers where the plant is being re-established.
Other threats to the plant include sand mining and indiscriminate use of vehicles in dune areas.
DOC's work
A pīkao recovery group has been set up with representation from a number of groups including DOC, Dunedin City Council, Otago Regional Council, Yellow Eyed Penguin Trust, the Runaka o Kāi Tahu, and other community conservation groups.
The Pīkao Recovery Group's work is based on the aims of the communities and groups who want to see pīkao re-established on the Otago coast. The legislative basis for this is found in the Conservation Act, the Resource Management Act, and the Treaty of Waitangi, which states:
"6. Cultural, historical, spiritual, amenity, and intrinsic values are the heritage of future generations and damage to these values is often irreversible."
"11. It is important to protect representative or significant natural ecosystems and sites of biological importance, and to maintain the diversity of New Zealand’s indigenous coastal flora and fauna."
A great number of beaches with high rankings in the National Sand-dune and Beach Vegetation Inventory contain remnant populations of pīkao. Some of these are considered of national importance, including populations in the Catlins.
What can be done?
A priority is to identify and protect natural stands of pīkao where it still exists. With community assistance, areas already invaded by marram grass can be restored to enhance biodiversity and the natural character of our coast.
Pīkao replanting and management programmes are underway throughout New Zealand. At the same time different organisations are doing a lot of work with pīkao propagation, from collecting seed through to nursery rearing and planting out.
A good example of this is the Yellow-eyed Penguin Trust's nursery at Company Bay on the Otago Peninsula. They produce some 2,500 pīkao plants a year. Many of these are for projects on land they own or manage, sometimes they can plant as many as a thousand on one site in a season. They also make plants available to individuals and organisations.
The Dunedin City Council also has a major pīkao planting programme and accesses plants from both commercial nurseries and the Yellow-eyed Penguin Trust. Examples of this kind of community activity, particularly with groups such as Coast Care, can be found throughout the country.