The phenomenal success of the South Island’s eradication and control programme for spartina, a highly invasive grass weed in estuaries, has impressed both Australian and Americans tackling the problem in their home countries.
Department of Conservation Ranger Graeme Miller outlined New Zealand’s success, particularly in the Southland Conservancy, at the recent Third International Spartina Conference in San Francisco.
Southland is one of NZ’s leading conservancies in spartina control, based on 16 years of trial work resulting in over 800ha of spartina reduced to under 1ha. Most of the South Island is now into eradication mode following a major cooperative effort between local authorities, communities and DOC.
Mr Miller said the spartina battle in Southland appeared nearly won, and DOC staff members were now working on the production of a ‘best practice’ guide for other areas.
“We currently have zero density of spartina within all estuaries in Southland,
and our programme in the past year has mainly centered on searching out any remaining small isolated patches of spartina.
“We have moved beyond control in most other areas of the South Island, and are now into eradication mode, getting rid of spartina completely.”
“The Australians were pleased to see the results of our work as they undertake control work in a similar manner to us, but still have a lot to do. Our work, particularly in Southland, has proved control and eradication can be achieved,” Mr Miller said.
“American interest in our work to bring spartina under control was very high, although they found it hard to believe we had done it so cheaply and simply.”
Mr Miller said the keys to New Zealand’s success were excellent interagency and community cooperation, the development in the last decade of more effective grass selective herbicides, the use of a helicopter for spraying spartina meadows and the introduction of the Argo, an eight wheel drive amphibious vehicle.
“The argo is fitted with a small spray unit, and has enabled us to get into previously difficult to access estuary environments,” Mr Miller said.
“The South Island now has only one large infestation believed left. It is in the Marlborough region at Havelock Inlet. However, a control programme is well underway between DOC and the Marlborough District Council.”
The Tasman is another area celebrating a spartina victory.
Tasman District Council Policy Planner Lindsay Vaughan said the long campaign in the Tasman area, begun in the 1970’s, was drawing to a successful close, particularly in the Waimea Estuary – once one of the worst areas in the South island for spartina.
“We’ve had a significant commitment of resources and dedicated teams from both the Tasman District Council and DOC. It’s been a long battle, but we are now at the tail end of it.”