Keeping invaders from gaining ground in Great Marsh

The proliferation of an invasive reed species in Newbury is threatening the Great Marsh, the tidal marsh that covers more than 17,000 acres from Rockport into southern New Hampshire.

A report by a group of Tufts University graduate students, delivered last month at a meeting of the Eight Towns and the Bay Committee, highlighted concerns about phragmites australis, also known as the common reed.

''It doesn't look like much, but we're looking at these as sort of the canary in the coal mine," said Peter Phippen, coastal coordinator for the committee. ''They weren't here two years ago. You don't want to have to come back and try to rehabilitate a marsh that's completely filled with phragmites."

The committee, a coalition of nine communities located along the Ipswich Bay, is made up of appointed representatives from Salisbury, Amesbury, Newburyport, Newbury, Rowley, Ipswich, Essex, Rockport, and Gloucester.

In 2004, Phippen and other local environmental stewards spotted 50 to 100 juvenile phragmites stands in a marsh just off the Plum Island River in Newbury, where they hadn't previously been seen.

''They're proliferating," Phippen said. ''Some of the bigger [phragmites stands] have been there for awhile, but the fact that there are a lot of smaller ones coming up is something we hadn't seen before. That's an issue: Why now and why out here?"

To answer that question, Phippen and others notified the Tufts researchers, who launched a study.

Phragmites australis is a species frequently found near the borders and upland areas of salt marshes. It proliferates at the expense of other species, robbing them of nourishment and sunlight.

Invasive species are of concern to environmentalists because they can alter the biodiversity of the ecosystem they invade.

Tim Purinton, community coordinator for Massachusetts Audubon, said that the presence of phragmites and other invasive species such as purple loosestrife, pepperweed, and marine invasives like the green crab is one of the greatest concerns of conservationists and others with an interest in the Great Marsh.

''The biggest issue is, what next?' " Purinton said. ''There seems to be a new invasive species every year. We always have to be vigilant and understand that the best way to control it is to get it right when it starts."

In the case of phragmites, proliferation may be an indicator that there is problem with the health of a tidal marsh, or the tide flow. The reed generally does not grow where water has a high level of salt content. In addition to the salinity issues, the report notes, the species will grow rapidly ''in areas where excess nutrients from runoff and pollution sources flow into coastal regions."

Because it is able to perpetuate itself in a healthy marsh, noted Lauren Baumann, one of the Tufts students, the species can also cause problems for other species.

''Even in this area, a fairly healthy marsh ecosystem, if there are stands, you need to address them," she said. ''They could cause problems in the ecosystem. They need to be addressed one way or another. . . Once they take hold it's very, very hard to get rid of them."

Phragmites have taken over some marshes in Connecticut and New Jersey, said Newbury Planning Board member Geoff Walker, a volunteer with several organizations that monitor the marsh. Locally, the species covers vast expanses of marshland in Salisbury, and Walker expressed concern that phragmites may one day dominate the landscape in Newbury as well.

The report was researched and compiled by Baumann, Jay Astle, Jenna Ringelheim, and Gina Filosa, students at Tufts' department of urban and environmental policy and planning.

In addition to background on the biology of the invasive species and the marsh's hydrology and ecology, the report includes case studies of phragmites management and control in other regions and recommendations for the Great Marsh.

''Immediately, what we're recommending is that a group goes out into the marsh and actually removes the juvenile stands so they don't get established," Baumann said. ''Over the longer term, we're recommending that there's data analysis and scientific research done to actually map where these existing adult phragmites stands are, as well as where the juvenile stands are located, and monitoring them over time to see if they're growing, shrinking, what's going on with them. Then creating some sort of program to address the phrag issues, specifically something that could be coordinated under Eight Towns and the Bay."

The report recommends that a coordinator position be created to work on the phragmites with the many stakeholders in the Great Marsh.

Phippen is seeking a grant to begin a monitoring program of the phragmites at Plum Island River, which he sees as the first step in implementing the report's recommendations.

The threat to the long-term health of the marsh is real, he said.

''With so many little stands all over the place, they'll just connect the dots eventually," Phippen said.