|An invasive species of water chestnut covers the surface|
of a lake in Fairfax County, VA. (Nancy Rybicki)
It springs to life each year in freshwater ponds and lakes as temperatures rise. By the middle of summer, the foliage is so thick and bushy at the surface that the water below is plunged into darkness, with hardly any oxygen seeping in from the air above.
Across Northern Virginia, the invasive aquatic plant has spread to dozens of locations, according to state and federal scientists. It looks a lot like Trapa natans, the water chestnut that has blanketed waterways on Maryland’s Upper Shore and the Northeast United States, but it isn’t.
|The invasive species of water chestnut, Trapa bispinosa,|
It’s a different type of water chestnut: Trapa bispinosa. And Northern Virginia is the first place it has been found growing in the country.
Biologists want to keep it that way.
If eradication efforts don’t ramp up soon, though, they warn that the species could spread beyond its current backwater haunts to the Potomac River and become a much bigger ecological headache. The 400-mile river’s currents could whisk T. bispinosa seeds just about anywhere, dampening hopes of containing the invasive plant, said Nancy Rybicki, a George Mason University professor and retired U.S. Geological Survey aquatic plant ecologist.
|The seed pods of Trapa bispinosa,|
“Here, we have a chance to manage it while it’s only in stormwater ponds, farm ponds and homeowners association ponds,” she said. “This horse is not out of the barn.”I've heard to many of these horror stories to get too upset, Piranhas in California, Fire Ants in Florida (which are, to be sure, pretty nasty), African Bees everywhere and Snakeheads in Maryland. Some invasive species do get established in places (the Piranhas never did), and while they do influence the local biota, and sometimes cause problems, the earth always fails to shatter.
The biggest obstacle, Rybicki said, is that no one seems to be in charge of dealing with the problem. There is no management plan to guide its removal and no agency with clear authority to tackle it.