Assessment of glyphosate treatment to eradicate the exotic wetland grass, Glyceria maxima, in the Ipswich River Wildlife Sanctuary :a report for the Massachusetts Audubon Society

Fisher, Ellen
Tom Wessels, MA
Department of Environmental Studies
In 1990 the Massachusetts Audubon Society (MAS) discovered several small patches of Glyceria maxima, a Eurasian grass not known to exist in the eastern U.S. in its Ipswich River Wildlife Sanctuary. Because observations and literature research indicated that this grass is a highly competitive plant with the ability to dominate wetlands, the MAS decided to eradicate it with the herbicide glyphosate before it could spread further and become a major problem. I analyzed MAS's Glyceria maxima eradication program carried out from 1993 to 1995. Along with Jim Macdougall, I also participated in a continuation of that program in the summer of 1997. This report covers the entire Glyceria maxima eradication effort to date and recommends future action. The patch of Glyceria maxima which was treated with glyphosate during 4 seasons since 1993 has not been eradicated. Because documentation of the treatments has not been consistently kept, and monitoring of the results has been inadequate, the reasons for this failure are not clear. I recommend that MAS undertake a rigorous Glyercia maxima research project which tests the efficacy of several eradication methods simultaneously so that a successful method can be systematically sought and information about Glyceria maxima which would be of use to conservation interests can be generated and shared.

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