Weed Salvinia molesta destroys Springfield wetland
IT’S one of the top 5 worst weeds in the world and doubles in size every couple of days. It’s already choked the life out of one Central Coast wetland and is in danger of spreading.
Central Coast
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ONE of the top five worst weeds in the world has taken over a Springfield wetland and is in danger of spreading.
The aptly named Salvinia molesta is listed as a “weed of national significance” and can double in size every two or three days with a “wet weight” of 400 tonnes per hectare.
The plant is an escapee from the aquarium industry and has now formed a thick mat of vegetation across the entire surface of the wetland, choking out all other plants, killing fish and frogs and driving away waterbirds.
Springfield residents have pleaded with Gosford Council to do more to remove and control Salvinia from the pond which they say was linked to a mosquito outbreak.
Springfield resident of 40 years Glenys Ray recently addressed a meeting of Gosford Council about the problem and said the pond been totally transformed from a “thriving ecosystem” used by animals, birds and aquatic life.
She said the first signs of the weed had appeared just before Christmas 2015 and had completely blanketed the pond within weeks.
“Mosquitos were in plague proportions last summer,” Mrs Ray said.
“People who have lived in the area for more than 30 years have never experienced anything like it,” she said.
“There is one case of Ross River/Barmah Forest fever that I know of.”
Mrs Ray said Central Coast Council was aware of the problem and had attempted to deal with it by using a type of weevil.
The salvinia weevil (Cyrtobagous salviniae) is originally from southeastern Brazil and was introduced into Australia by the CSIRO in 1980 to combat the growing threat of salvinia.
Salvinia weevils were first released in Australia into Lake Moondarra near Mount Isa in Queensland and, in less than 12 months, destroyed an estimated 30,000 tonnes of weed to clear the 800-hectare lake.
However, their success has been much more limited in cooler NSW.
Councillor Rebecca Gale Collins successfully moved that council staff assess the situation and remove “sufficient amounts” of the weed within the existing budget.
Cr Gale Collins also moved that if it was not possible within the existing budget, that State Government funding be sought to assist.
“Springfield and Holgate ponds are presently in a disgraceful condition,” Cr Gale Collins said.
“We need swift operational action to clear a large portion of this weed off the ponds for the weevil beetle system to work,” she said.
“The big problem is that salvinia doubles every 2-3 days, Weevils need to be replaced.”
Cr Gale Collins said experts believed that the weed needed to be reduced and raked out now for the weevil treatment to be effective.
“Council must act swiftly while simultaneously seeking grant assistance,” she said.