2007-11-08 / News

Educating islanders about invasive plant effects

By Dotti Farrington

Jamestown Conservation Commissioners last month decided to develop a brochure for homeowners to be able to identify and to remove invasive plants from their properties. The educational pamphlet will supplement the commission's effort to identify and control invasive plants on town properties and along island roadsides.

Some 77 different plants at Beavertail, Fort Wetherill and Fort Getty Parks were identified in 2005 and 2006 by researchers Lisa Gould and Meg Dyer for the Invasive Plant Atlas of New England. Jamestown commissioner Cathy Roheim reported that some patches of plants have reached stages of concern.

The local conservationists this summer launched work to make a plan to bring the invasives under control. They said that environmental specialists generally concede it may be impossible to eliminate most invasives, but efforts to limit growth and problems can be successful.

Commissioners here also reported that invasive trees at the North Pond Reservoir grounds have reached proportions of concern and efforts are being made with the town Water and Public Works Departments, and the Tree Committee, to try to curtail their continued spread.

Chairman Christopher Powell said the board will need to find and apply for funds to print the homeowners' publication. Other commissioners said area organizations have data about problem plants and the information will be helpful in developing a guide specifically for Jamestown.

"We need to tell residents about the problems so they will know what is not wanted in their yards," Roheim commented. 'We need to give them information so they will know what not to plant and what to remove."

Jamestown's commissioners launched control of invasive plants in July as one of several multiple year goals they set for themselves.

Powell and Commissioner Pat Driscoll raised concerns about reports of invasive trees being identified on the island. "It's important that they be removed before the species takes over," Driscoll said.

Commissioner Jennifer Talancy identified the Norway Maple as a significant threat to elm, ash and black cherry trees by overshading those species. "If we don't act now to stop its spread, Jamestown woods could become mono-culture and ugly," she commented.

Knotweed targeted

Talancy also spoke at length about Japanese knotweed in July. She reported the knotweed apparently was imported and planted about 20 years ago as a screening plant at West Reach Estates and is spreading to neighboring woods, including town-owned property on North Main Road. She suggested the invasive plant could not be eradicated, but could be controlled.

The knotweed chokes out native plants, and can be problematic in numerous ways. It spreads quickly to form dense thickets that exclude native species and are of little value to wildlife, leading to it being described as an environmental weed. Seasonally, the plant leaves a mass of dead stems that further inhibits native plant regeneration and leaves land vulnerable to erosion and flooding.

The knotweed invades ecologically valuable wetland habitats. Common names include: Japanese or Mexican bamboo, Japanese fleece flower, donkey or Sally rhubarb, German sausage, and peashooter plant.

Talancy is working to collect data about the knotweed, especially about ways individuals and the town can best control it.

Commissioners are gathering data, including photos, about all undesirable plants being found in Jamestown, to develop into an education project. The information will be used to let property owners know what can be done, and to encourage interest in developing a volunteer corps to otherwise cope with the invasive plants.

Generic data

Invasive plants are most frequently known as, and sometimes dismissed, as weeds, but those concerned by unwanted growth also call them introduced species, non-indigenous plants, non-native and alien species, and noxious or exotic growths.

They harm the habitats they invade economically, environmentally or ecologically, usually by choking out desirable, native plants. Some non-native plants have not caused damage, but most do overtake their habitats. Environmentalists say it often takes 20 years or more to control a growth that has taken over an area.

All species compete to survive, but invasive species appear to have specific traits or combinations of specific traits that allow them to outcompete native species, specialists report. Common invasive species traits include fast growth, rapid reproduction, high dispersal rates, ability to adapt to suit current conditions, and tolerance of a wide range of environmental conditions, among other characteristics.

An introduced species might become invasive if it can out-compete native species for resources such as nutrients, light, physical space, water or food, it was explained. Invasive species often coexist with native species for an extended time and gradually the superior competitive ability of an invasive species becomes apparent when its population grows larger and denser.

Biological species invasions alter ecological systems in a multitude of ways. Land clearing and human habitation put significant pressure on local species and disturbed habitat is often prone to invasions that can have adverse effects on local ecosystems, changing ecosystem functions, environmental sources explain. Invasive species can change the functions of ecosystems. Harmful effects of hybridization have led to a decline and even extinction of native species.

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