Restoring Western Port saltmarshes from the air
Western Port residents may have seen helicopters flying over saltmarshes at Bass, Lang Lang and Kooweerup over recent months as Melbourne Water used innovative aerial spraying techniques to eradicate introduced grass species.
Spartina is a weedy grass introduced from Europe in the 1920s as a means of managing erosion. The plant’s strong matt-like growth stabilises stand banks, but also outcompetes native saltmarsh plants.
Since its introduction Spartina has taken over several saltmarsh areas in the Western Port region, destroying native plants and driving out native animals.
In 2015 Melbourne Water accepted a recommendation from Ecology Australia to eradicate all Spartina grass from Westernport intertidal zones over the next decade. Intertidal areas occur where freshwater river channels meet ocean waters, creating a saltmarsh.
Melbourne Water Manager Regional Services (South-East) John Woodland said the innovative aerial spraying method was critical to delivering on this commitment.
“Spartina grows in salt marshes that are boggy and thick with mangroves, so getting in and out on foot is very inefficient,” he said.
“Doing this important work by helicopter saves significant time and money and will help us deliver our desired result of eradicating Spartina in Western Port by 2025.
“With the removal of Spartina we hope to see native saltmarsh plants begin to return. These also provide natural habitat and feeding grounds for native wildlife.
“Prior to Spartina, these saltmarshes provided feeding grounds for protected species such as the Orange Belly Parrot, which we hope will eventually return to Western Port.”
Mr Woodland said the Spartina grass had grown so rampant it was even impacting tidal flows.
“What we are now seeing is the artificial creation of unnaturally deep and narrow intertidal canals because the grass is holding back the banks so much. It is impacting the natural structure of the waterways themselves, so this work will help to return these channels to their normal state over time.”
The aerial spraying process involves a long snorkel being lowered from a helicopter into a salt marsh. The aerial crews pinpoint the Spartina and a spray nozzle coats the plant evenly while ensuring the spray does not enter the waterway.
The herbicide itself is a special composition that only targets Spartina grass and has no impact on native saltmarsh plants or animals.
Helicopter spraying is not active in the winter months but residents can expect to see helicopters at work again from mid-spring until mid-autumn each year until the Spartina is fully eradicated.
Check out the project video to learn more.