Brazilian Elodea, a common aquarium plant, poses a threat to lakes and ponds.
COURTESY INTEGRATED LAKES MANAGEMENT
A contractor doing routine maintenance discovered a potential invader in two small ponds last summer, but Lake County biologists were astonished when they looked again in January.
Beneath 8 inches of ice covered by 6 inches of snow, the Brazilian Elodea - an aggressive plant that can take over healthy lakes and ponds - was thriving.
"It was very bright green and growing very nicely," said Mike Adam, senior biologist with the Lake County Health Department.
"It's an exotic species that's rarely shown to survive the cold winters. That was a bit alarming."
The find in the ponds, owned by the village of Libertyville, has prompted the health department to issue an alert.
"There is interest in the region to get rid of this before it spreads," Adam said.
So far, the plant has not been detected elsewhere in Lake County and the village is treating the two populations in its ponds.
Until 2008, the Midwest Invasive Plant Network reported this South American exotic was known in only 17 counties in the Midwest and Ontario. Only one known population, in central Minnesota, survived the winter.
Available in many pet stores or water nurseries under the name "Anacharis," the plant is commonly used for decoration or to regulate the oxygen level in aquariums.
"My guess is somebody dumped an aquarium," in the pond in Libertyville, said Sarah Denny, project manager for Integrated Lakes Management, the company that had been maintaining the connected ponds for Libertyville.
The plant is feared for two reasons. Not only does it overpower other water plants, but it also presents a thick blanket of vegetation that can become an impediment or hazard to boating.
"It's like any other weed on land. It can become incredibly aggressive," Denny said.
"You're creating a bad environment for your ecosystem and creating aesthetic issues. Other places that have had this stuff, you can't put a boat in the water because it's so crowded."
Adam noted that managing invasive water plants can be expensive and time consuming.
To stop the spread of Brazilian Elodea, health department officials say to dispose of overabundant water garden or aquarium plants in the garbage, and not in any body of water.
Aquatic plants should be rinsed before planting and kept contained in a water garden. Also, recreational vehicles, trailers and equipment should be cleaned before leaving a lake or river, authorities urge.
"In an aquarium it looks nice," Adam said, "not in a body of water."
Anyone who suspects the plant is present in a local waterway should call (847) 377-8030.