Marram grass
Target eradication - marram grass
Marram grass
An ambitious programme to eradicate marram grass from the dune systems at Mason Bay, Rakiura National Park is now in its fourth season. Staff have learnt how to control vast areas of marram and are showing other Conservancies how it's done.
The dunes here are one of New Zealand's biggest remaining unmodified dune systems and have high conservation value. Good populations of pingao remain, flocks of New Zealand dotterels feed and nest here and kiwi sign is common. Threatened plants of the dune community include Gunnera hamiltonii and Euphorbia glauca, but all are threatened by the vigorous and invasive marram.
Spraying marram grass
Marram was planted at Mason Bay as part of efforts to farm the area in the 30s and 60s. Mike Hilton of Otago University's Geography Department has calculated that unchecked marram will occupy all available habitat in the dune system by the year 2030 and that marram and pingao cannot coexist, regardless of initial densities of pingao. All efforts to control the marram now will be cost effective in the long term.
Otago continue to monitor the implications of the work being carried out here.
Each January the marram spraying project managed by Eamon Ganley of Stewart Island Field Centre has included DOC staff from around the country as a staff development opportunity. Control is by use of 'Gallant' a herbicide specific to grasses (pingao is a sedge) and an 'Argo' - an 8-wheeled vehicle, complete with a 250-litre spray tank and two long hoses under pressure from a petrol pump.
Results are impressive and the choking cloak of sage-green marram is being gradually drawn back to reveal creamy white dunes topped with a crest of golden pingao.
The project must expand in future to control areas of marram to either side of the dune field and achieve the target of eradication. A strategy has been developed that, subject to funding, will recreate an intact dune system within our newest national park. The dune system extends up to 3km inland and is easily accessible from the Great Walk tramping hut at Mason Bay.
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