Print PageEuropean frogbit (Hydrocharis morsus-ranis L.) is a free-floating aquatic macrophyte that is invasive in North America. It is native to Europe and was first introduced to North America in 1932. It has since spread south into the Great Lakes region at a rate of 15.6 km/year. Since it has the potential to be ecologically, economically, and socially costly, it is important to devise an effective management strategy for controlling its spread. Our study was conducted in Oneida Lake, NY to gauge the effectiveness of two physical control methods - hand pulling and shading, and to assess the impact of each method on a number of water quality parameters as well as the impact of this plant on its invaded ecosystems.
Results/Conclusions
Results showed that European frogbit in small coverage increased chlorophyll concentration and benthic invertebrate richness whereas dissolved oxygen, nitrates, and phosphorus were not affected. After applying the two control methods, shading removed 100% European frogbit but there was no significant effectiveness of hand pulling. These methods did not affect nutrients when compared with frogbit infested sites or frogbit free sites, probably due to well mixing of the experiment area. However, both shading and hand pulling improved growth of submerged plants compared to frogbit infested sites but plant growth was still the best in frogbit free sites. Our study suggested both hand pulling and shading could be viable options for controlling and eradicating invasive European frogbit. Hand pulling needs to be conducted more frequently to be more effective and shading may be refined in the future to become more environment friendly.
