The list of New Zealand's native plants is growing after the discovery of new species.
A panel of scientists from the National Institute of Water and Atmospheric Research (Niwa), Landcare Research, Auckland Museum Herbarium, the University of Canterbury School of Forestry and the Department of Conservation (DoC) has produced a conservation list after a new assessment of New Zealand's plants last year.
The last assessment was done in 2008 and assessed the threat status of 2530 plants. The latest review assessed an extra 50 plants and lists the threat status of 2580 plants.
When the 2008 assessment was conducted scientists thought there was just one species of Cook's scurvy grass but recently published research recognises 11 new species of Cook's scurvy grass, all split from the known single species.
A total of 243 plants were listed as threatened in 2008. This has increased by 46 to 289 in the 2012 listing.
This is due to a number of factors. These include the fact that an extra 50 plants were assessed in 2012 plus a range of environmental factors. These include loss of habitat, browsing by pest animals such as possums, rabbits and goats, the spread of plant diseases and competition from weeds.
"The number of plants on the threatened list highlights the need for agencies, such as DOC, councils, Landcare Research, NIWA, universities and museums to work together with farmers, developers, iwi and community groups to ensure we are protecting our threatened plants," said Dr Peter de Lange, DoC principal science advisor and senior author of the new threat list.
"The knowledge gained from the listing process is being used by DOC, councils, iwi, the private sector and community organisations to carry out conservation programmes throughout the country that are benefiting our native plants and the wildlife they support."
An example of a native plant being brought back from the brink of extinction is the Kermadec koromiko, a shrub found only on Raoul Island. It was thought to be extinct due to browsing by goats. A single plant was discovered on Raoul after goats were removed from the island in 1983. Clearing rats from the island in 2004 accelerated the plant's recovery. There are now around 1000 adult Kermadec koromiko plants on a number of sites spread across the island.