In 1990 as Tutukaka Marina Manager I created a garden of Poor Knights plants for visitors and locals, Northland Department of Conservation were impressed by the idea and granted a permit to collect plants from the islands. A party of elders of the descendants of the Poor Knights people was visiting the islands to investigate the possibility of burying the important dead back on the islands. Bad dreams had by one of the party the following night but paid to this idea. However, during this visit one of the party found a seed pod of a moth vine. Considered a very serious weed, it was important to survey the extent of the invasion. In my capacity as Marina Manager I was able to organize an island drop off and pick up. Over a period of two years several visits were made for up to ten days at a time. Random wanderings did find weeds, but a more systematic approach was needed. I was asked by the department to put together a weed plan. Out of the forty five exotic plants growing on the islands four main weeds were identified as likely to have adverse effects on the ecosystem. Pampas grass, Mexican devil, Mist flower and Moth plant they can form dense swaths producing thousands of wind blown seeds. In 1996 the Poor Knights weed eradication plan was developed, it was made up of six key components:
- Management areas and regimes.
Consideration was given to the location of existing weed sites. Almost all weed infestations occur in areas of disturbance within exposed coastal faces, shrub land and broadleaf forest these are searched twice a year to coincide with the earliest flowering weeds. In mature Metrosiderous excelsus or Pohutakawa there is almost a total absence of weeds and these are sweep searched every two years.
- A database for recording sites and control work undertaken.
- Aerial surveys undertaken every second year over inaccessible cliff faces and difficult to find adult moth vines. A technique of throwing a rock with bright colored flagging tape out the window of a helicopter was used.
- Searching techniques were developed.
- Standardized site marking with plastic numbered tags and plotted onto a field map.
- Strictest hygiene protocols were set.
Although reinvasion from the main land is always going to be a threat to the islands the main threat is the spread of weeds already established on the islands. The weed plan turned out to be better than any one could have imagined. It has gone on to form the basis of many weed plans on other off-shore islands.
Guy & Sandra Bowden are owners of Tawapou Coastal Natives Plant Nursery on the Tutukaka Coast. Guy grew up on the Tutukaka Coast and has been passionate about NZ native plants all his life. His interest was kindled by his conservationist parents who began protecting sections of native bush and pohutukaka on the cliffs of the property over forty years ago. Guy talks about The Poor Knights Islands in relation to location & geology; history; plants and birds on the islands; reptiles, insects and snails on the islands; marine life and the 1996 weed eradication programme.
