Lakeville and East Freetown Massachusetts
LONG POND ASSOCIATION
An Update to the Report May 8, 2002
Summary of Expert Opinion on Mechanical Harvester Use
"I think harvesting is the worst choice you can make to manage a new infestation of any exotic weed, including Cabomba and variable leaf watermilfoil. Harvesters create fragments which help to spread the plant."
Dr. John D. Madsen, Minnesota State University, Mankato
Department of Biological Sciences
(Referred by Dr. Kurt Getsinger, US Army Corps of Engineers)
"Many invasive plants, including Milfoil and Cabomba, proliferate in water bodies as a result of fragmentation. In fact, fragmentation is probably the most common way these plants spread and infest water bodies. Therefore, any method of management that encourages fragmentation should be discouraged. - We would not recommend the use of mechanical harvesting for the management of Milfoil and Cabomba in Long Pond."
Dr. Lee Lyman, President, Lycott Environmenal Inc.,
"Mechanical harvesting can be an effective control technique for some aquatic plant species, such as water lilies and water chestnut, which propagate primarily through seed dispersal. However, Cabomba caroliniana is a perennial plant that spreads primarily by stem and rhizome fragmentation. Although mechanical harvesters cut the tops of plants and collect the cuttings for removal from the lake, many plant fragments that are not collected can start new colonies. In lakes with localized infestations, harvesting can actually accelerate the spread of Cabomba to uninfested areas because of its ability to regenerate from fragments."
Robert Hartzel, Senior Water Scientist, GeoSyntec Consultants,
"---This leaves mechanical harvesting, which could actually do more harm than good if fragments are not carefully collected. Both fanwort and milfoil spread by fragmentation, and harvesting often promotes such dispersal."
Dr. Kenneth Wagner, ENSR, Willington, CT
Organizer of 2002 Annual Meeting of New England Chapter of the North American Lake Management Society
"Although many claim that harvesting is environmentally superior to herbicide use, most neglect to consider that harvesting removes large numbers of macroinvertebrates, semi-aquatic vertebrates, forage fishes, young-of-the-year fishes, and even adult gamefishes. The harvester acts as a large, nonselective predator "grazing" in the littoral Zone."
From: "Mechanical Control of Exotic Aquatic Plants",
US Army Corps of Engineeers, Jacksonville District, June 2000
Summary of Expert Opinion on Mechanical Harvester Use for Cabomba