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Lake Champlain Emergency
Rapid Response to Water Chestnut Infestation Launched
by Nicole Ballinger, Lake Champlain Basin Program
The exotic plant known as the water chestnut (Trapa natans) is common in the southern portion of Lake Champlain, but when it was found in July in remote wetlands in the Missisquoi National Wildlife Refuge—on the northern Lake—an alarm sounded. Scientists have long worried that Missisquoi Bay’s shallow waters could be inundated by water chestnuts, compounding the area’s existing problems with blue-green algae. The refuge is home to endangered species that rely on the wetlands’ native plants. If the water chestnut became established, it would displace native plants, causing havoc throughout the food web.
The concerns prompted fast action. Barely a week after the initial sighting of the plants, staff from the New York and Vermont environmental agencies, the Lake Champlain Basin Program, the U.S. Fish and Wildlife Service, the Lake Champlain Committee, and several volunteers launched a “rapid response,” as it’s called in aquatic nuisance species management parlance. Pontoon boats ferried more than two dozen people and their canoes and kayaks four miles to the infested wetlands, which are sensitive nesting habitat for endangered black terns. These wetlands are normally off-limits to visitors, suggesting that water chestnut seeds were carried there by waterfowl, not humans.
Once on site, the rapid responders used the canoes and kayaks to carefully search the wetlands for the water chestnuts, which were often hidden in native pickerel weed and water lily patches. When they found a water chestnut plant, they pulled it out by hand, removing it before the plant had the chance to drop its seeds. In just a half-day, the crew loaded two entire skiffs with piles of the plants.
Had the waters been less sensitive, efficient mechanical harvesters could have done the job. But by carefully hand-pulling water chestnuts, native wetland plants were not destroyed. Although it requires a lot of labor, pulling by hand is effective. In 1998, crews hand-pulled 2,160 pounds of water chestnuts from Roger’s Marsh on southern Lake Champlain. According to the Nature Conservancy, just three plants remained in that area by 2004.
The response to the water chestnut invasion in Missisquoi Bay drew plenty of media attention, and it was even a top story on the local television news progams. A good news story too, as the wetlands were declared free of chestnuts—for now. Refuge managers will closely monitor the affected areas to make sure that none of the plants survived this initial response, and to sound the alarm again if a return trip by the responders is needed.
Nicole Ballinger is the Communications Coordinator and Webmaster at the Lake Champlain Basin Program, which NEIWPCC supports by providing program guidance and financial management.