Conservationists take up fight against invasive water weed
Monday, March 17, 2014
SPRINGFIELD (AP) — Conservation officials say an invasive water weed that has been discovered in southwest Missouri needs to be contained before it spreads to other areas.
Hydrilla is sometimes called the “Godzilla of invasive plants” because of how it takes over bodies of water and devastates fish habitat by lowering oxygen levels in the water and eliminating fish food sources, said Kara Tvedt, fisheries management biologist with the Missouri Department of Conservation.
“It’s the perfect weed because it can grow in deeper water than most plants and out-compete native plants,” she told the Springfield News-Leader. “Once it reaches the surface it starts branching out and shading everything out below.”
Left uncontrolled, hydrilla plants can form mats so thick that some states in the South have to use special harvesting machines to cut paths through hydrilla beds so boats can pass. Hydrilla mats also can clog water intakes and render swimming areas unusable if not controlled.
The state Conservation Department has been working with property owners on ways to keep it from spreading to other waterways since it was discovered in Greene County ponds in late 2012, and later in ponds in Dallas and Warren counties.
Tvedt said it’s not known how the plant got into the Greene County ponds, though it can hitch a ride in boat bait wells, on boat trailers and even in the digestive tracts of ducks that eat it.
“Some waterfowl do like to eat hydrilla, and parts of the plant can pass through their digestive tract and still be viable,” she said.
The plant, which is native to Africa and Southeast Asia, arrived in Florida in the 1950s as an aquarium plant, according to the Center for Aquatic and Invasive Plants at the University of Florida. Since then it has spread to at least 19 states and is on the Federal Noxious Weeds list.
Hydrilla can be killed with water-based herbicides. Also, the weed can be tamed by introducing grass carp, which have voracious appetites for the plant, into a pond.
Once it becomes established, however, hydrilla is difficult to control because of its ability to grow from roots embedded in the bottom of a lake, and from bits and pieces of the plant that form new plants when they break off.
Tvedt expects a major educational push to start in early summer so people will know how to identify the plant.
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