In the 1930s, planting the hardy grass Spartina around Northern Ireland's coastline was seen as an ingenious way to protect the shore against erosion.
But now scientists at the University of Ulster at Coleraine are devising ways to beat back this invasive species that threatens to wreck the habitat of wildfowl and waders.
Through a series of trials, Mark Hammond, an environmental scientist at the university, has concluded that while the salt-tolerant grass cannot be eradicated, it can be controlled.
In the meantime, Spartina is continuing to take over Northern Ireland's estuaries, which are of international importance for birds such as over-wintering pale-bellied Brent geese.
"The spread of Spartina into wildfowl and wader feeding areas is seen as a threat to bird populations," Hammond said.
The grass grows in clumps that provide an anchor for tidal sediment that would otherwise be swept away by the water and so increases marsh elevations where it is planted.
This makes it perfect for coastal protection but also allows it to out-compete native plants, such as the seagrass Zostera, an important foodsource for wildfowl. In addition, Spartina prevents wading species from getting at invertebrates in the mud.
Hammond's study suggested it was possible to wipe out 95 per cent of Spartina in an area within a year by treating it with dalapon, one of two herbicides licensed for use in Northern Ireland's estuaries, or by smothering it with black plastic sheeting for six months.
The treatment also blighted native species, but they subsequently recovered strongly. Invertebrate numbers appeared unaffected.
However, this strategy was not practical for a complete eradication as the use of herbicides was forbidden in areas of the Northern Ireland's coast designated as shellfish zones.
Hammond proposed a limited attack on Spartina to create a patchwork of different habitats, preserved through constant vigilance against the encroachment.