25-Year Hunch Pays Off
By Des Williams
News release from Department of Conservation, Waikato Conservancy.
Waikato-based Department of Conservation staff have discovered a healthy population of the nationally endangered plant
nau, or Cook's scurvy grass (Lepidium oleraceum), on a remote western Waikato islet near Albatross Point, south of
Kawhia harbour.
The three-member team led by plant ecologist Andrea Brandon was helicoptered onto the islet, which has been regarded
for 25 years as a likely site for the species and had earlier this year been identified as top priority for an on-ground
survey. Dr Brandon, accompanied by DOC Biodiversity Programme Manager Dave Smith and Ranger John Keene of Te Kuiti,
returned from the excursion to confirm that more than 80 Cook's scurvy grass plants are growing on the islet, in an area
about half the size of a rugby field.
The islet is about 150 metres off-shore and is inaccessible except by helicopter because of dangerous currents, and
sharks are also quite common in the surrounding water. "We were fortunate that New Zealand Steel had a helicopter
working in that area and the company sponsored our access to the difficult site. We found the plants growing under the
natural cover provided by taupata (Coprosma repens) along the sheltered side of the 30-metre high islet", Dr Brandon
said.
"Although it is named Cook's scurvy grass, the plant is actually a type of cress that grows to about one metre tall.
When Captain Cook voyaged here in 1769, the plant was recognised as a valuable source of Vitamin C and was famously used
as a food source for the vitamin-deprived crew, hence the common name of Cook's scurvy grass. It was recorded as
abundant back then."
Dr Brandon said Cook's scurvy grass has been recorded at just eight locations along the west coast of the North Island,
with only two of those sites containing more than say 20 plants.
"This is a very significant find for the region, and indeed for the whole of the North Island, where this species is
now seriously at risk of going extinct. We collected samples for a nationwide DNA finger printing exercise being
undertaken by Landcare Research and Department of Conservation scientists. They, together with the coastal cress
recovery team, hope to determine through a nation-wide survey of surviving scurvy grass populations where the key sites
are, to help maintain and enhance genetic diversity in this intriguing member of the cress family."
ENDS