SUCTION HARVESTING OF EURASIAN WATERMILFOIL AND ITS EFFECT ON NATIVE PLANT-COMMUNITIES

Seven sites on Lake George, New York, were selected for control of Eur asian watermilfoil by a diver-operated suction harvester. Prior to suc tion harvesting, ten 0.1-m(2) biomass samples were collected from each site. Samples were randomized within the area to be harvested, sorted by species, dried and weighed. A grid system of 36 contiguous 1-m(2) quadrats was also located within each of the treatment areas. The spec ies present and their relative percent cover in each quadrat were reco rded prior to harvest, shortly after and 1 year postharvest. A substan tial reduction in the biomass of milfoil at all sites was noted as a r esult of suction harvesting. One year after harvest, the impact of har vesting on the native plant community included a greater number of spe cies per unit area and reduced biomass and percent cover at a majority of the treated sites.