Alien plants invade state's waterways

By Martin Finucane, Associated Press writer

WATERTOWN -- Anna Eleria plunges her hand boldly in the murky green river and pulls up a dripping, alien-looking thing.

Stems radiate from a central hub ending in fan-shaped leaves. Spiky seeds nestle underneath. And a long tufted root hangs down, apparently designed to trail into the depths.

"It's not slimy," the environmental scientist with the Charles River Watershed Association says reassuringly. "It's a plant."

But the water chestnut is an invader.

The Charles is one of many bodies of water around the state this summer under attack from rapidly spreading plants that aren't native to the United States.

Water chestnut and other plants, such as Eurasian watermilfoil and fanwort, may spread especially aggressively because they have left behind predators and other problems that kept them in check in their native habitats, experts say.

Add in the possibility that the water is nutrient-rich because of fertilizer runoff from lawns or farms or leaky septic systems and their growth can be explosive.

The plants can take over a pond or a slow-moving river and elbow aside other plants, as well as make the body of water unfit for swimming, boating or fishing.

"It's like a cancer," said Sen. Susan Fargo, D-Lincoln, who has proposed a $1 million measure at the Statehouse to track the spread of the plants and help communities get rid of them.

"It's an economic issue because of the effects on tourism and property. It's a public safety issue ... and it's an environmental issue," she said.

Exact data on the plants' spread across the state isn't available, state officials and experts said.

Rick McVoy, an environmental analyst with the state Department of Environmental Protection, said a four-year survey of 965 lakes and ponds completed last year found about 30 percent were host to non-native, invasive plants.

But that survey didn't cover all of the state's 3,000 lakes and ponds and the problem has probably worsened, McVoy said.

Barre Hellquist, a biology professor at the Massachusetts College of Liberal Arts who is an expert on non-native aquatic plants, said lakes and ponds are in worse shape in the eastern part of the state.

"In the eastern part of the state, I'd be willing to say 60 percent to 70 percent of them have got problems. As you get into the more remote areas, there's less and less problems," he said.

News reports in the past few years have told of problems with the aquatic plants cropping up around the state, from Pittsfield to Newburyport to Plymouth.

On the Charles, water chestnut infestation has been a serious problem for several years.

And near the Watertown Yacht Club on a recent sunny day, a mat of the light green plants nearly clogged half the river, while an orange harvester chugged nearby, busily chopping the weeds out of the stream.

Dan Driscoll, project manager for the Metropolitan District Commission, said that several years of aggressive harvesting by the MDC -- costing $150,000 to $190,000 a year -- appear to have paid off, with markedly fewer plants seen this year.

McVoy, the state analyst, said water chestnuts have been a problem on the Concord, Sudbury and Assabet rivers and the plants have now been sighted on the Connecticut, Neponset, Parker and Nashua Rivers.

In western Massachusetts, Eurasian watermilfoil has been the big problem -- and McVoy said the problem appears to be moving eastward.

In Pittsfield, for example, 617-acre Lake Onota was infected beginning five years ago, said Bob Race, president of the Lake Onota Preservation Association.

By last summer, a quarter to a third of the lake was covered with the plant, he said.

"It takes over and grows and comes to the surface and forms dense mats. It just essentially blocks out everything else. It's dangerous to the fishery. It's absolutely impossible to swim or boat through," he said.

"It's not something people like to swim in. It does tend to wrap around things and it can become very threatening" to those who aren't expert swimmers, he said.

The solution for Lake Onota: a two-year, $125,000 program of chemical treatments that began in June, which Race says appears to be working.

Beyond mechanical harvesting and chemical and biological treatments, the experts are looking to preventive measures.

They want to educate boat owners that some of the plants can be spread from pond to pond simply by shreds of the plant hanging on an unwashed propeller.

They also want a ban on the sale of some aquatic plants by the aquarium and water garden industry.

Fanwort, for example, which is a pest in some lakes and ponds, is sold, and experts believe it may be spread when people dump out their aquariums, said Carol Hildreth, a spokeswoman for the Massachusetts Congress of Lake and Pond Associations.

Fargo, whose bill is still in a legislative committee, said her bill would address a growing problem.

"Each year that we don't do this, the plants get worse. The only way to combat it is to just keep at it," she said.