Method of Removal of Aquatic Pond Weed Variably Impacts Presence of Potentially Toxic Cyanobacteria

Lakes often exist in two alternative stable states: clear waters dominated by submerged aquatic vegetation and turbid states with an abundance of phytoplankton. Management decisions must balance the value of primary producers with recreational use. We monitored the phytoplankton community surrounding removal of invasive Potamogeton crispus , a submerged aquatic perennial. Focus was given to presence of cyanobacteria, which may thrive in the absence of macrophytes by virtue of phosphorus that would otherwise be stored in plant biomass. Results demonstrate that macrophyte removal can lead to an increase in cyanobacteria dominance, with sustained impacts after hand removal.