Short-Term Summer Drawdown as a Potential Tool for Management of MonoeciousHydrillia: Impacts on Hydrilla and Non-Target Vegetation

摘要

Studies were conducted during the 1993 and 1994 growing season to determine thepotential of a short-term summer drawdown for management of monoecious hydrilla in impoundments. In 1993, hydrilla was grown in an outdoor flow-through mesocosm system in sand or silt loam hydrosoils and exposed to dewatering for periods varying from one to four weeks. Substantial regrowth and tuber production occurred by the end of the growing season following a one-week drawdown. The drawdown simulation was repeated in 1994 to determine the effects of dewatering on non-target vegetation. Hydrilla and four species of native vegetation were grown in sandy hydrosoil and exposed to dewatering for a period of two to four weeks. The results of the study suggest that a short-term, summer drawdown of two to four weeks duration will be sufficient to kill most of the existing vegetative biomass of monoecious hydrilla and suppress the formation of its primary overwinterig reproductive structures, the subterranean tubers.