Exotic Species Monitoring and Management
Point-intercept and meander surveys are conducted yearly on the Grandmother Falls Flowage, located in Lincoln Co., to document the presence of purple loosestrife (Lythrum salicaria), giant reed grass (Phragmites australis), curly-leaf pondweed (Potamogeton crispus), and Eurasian water milfoil (Myriophyllum spicatum). Point-intercept surveys allow the systematic sampling of submerged plants within project waters and ensure all areas of the littoral zone are visited.
Eurasian water milfoil (EWM), native to Eurasia and northern Africa, has been documented in large abundance upstream in Lake Mohawksin, and there is fear that the milfoil will spread downstream and become established throughout the flowage. NES has identified areas within the flowage that do contain EWM; however, the abundance of the plant is not yet problematic. If EWM becomes established in high abundance throughout the flowage, it could threaten aquatic plant communities and fish predator prey relationships.
Purple loosestrife, native to Europe, has rapidly spread throughout the flowage since 2006. This perennial can overrun wetlands and eliminate almost all other vegetation if left unmanaged. From 2007-2010, all loosestrife documented along the flowage was removed manually and chemically by NES staff.
Giant reed grass and curly-leaf pondweed were not identified within the flowage.
NES completed the 5-year monitoring project in 2011 with the submission of the final annual report.