Aquatic Plant Research > Invasives > Management and Control > Eurasian Watermilfoil (EWM) Control > Synthesis of Current Research on Control of Invasive Aquatic Species
Aquatic Plant Research
Synthesis of Current Research on Control of Invasive Aquatic Species
Following several years of data collection, DNR Science Services researchers are synthesizing the findings of different treatment strategies to determine the most effective way to approach Eurasian watermilfoil management in the state of Wisconsin.
Recognizing the need for a long-term ecological data set on Eurasian watermilfoil populations to better understand the roles that management, establishment time, and interannual variation have on Eurasian watermilfoil frequency of occurrence and biomass, DNR Science Services have collected full-lake aquatic plant data on 28 lakes across three WI ecoregions from 2005-present. Lakes represent both actively managed and unmanaged systems, and also represent newly discovered as well as established populations. Long-term ecological and management data will allow for examination of multiple lakes for long-term Eurasian watermilfoil natural variation as well as over differing management scenarios, and provide managers and policy makers with science-based information. This dataset is the first of its kind to examine multiple lakes for long-term Eurasian watermilfoil variation over differing management scenarios.
DNR staff in conjunction with the Army Corps of Engineers formed a cooperative research agreement to learn more about the behavior of aquatic herbicide applications in a subset of Wisconsin lakes and flowages. Data were collected by the Army Corps of Engineers, DNR regional staff, multiple lake management consultant agencies, as well as private citizens. The first two years of data have been compiled into a synthesis report that will be finalized soon in order to help guide future aquatic plant management decisions.
DNR Science Services created a factsheet in order to provide easily accessible information on the current scientific understanding of ecology and long-term management of Eurasian watermilfoil. Factsheets are utilized internally and by multiple statewide and national organizations and citizens.
DNR staff in conjunction with the Army Corps of Engineers formed a cooperative research agreement to learn more about the behavior of aquatic herbicide applications in a subset of Wisconsin lakes and flowages. Specifically, researchers focused on determining what 2,4-D and/or endothall concentration exposure times are needed under varying operational conditions to improve control of invasive species while minimizing native impacts. Based on the first two years of the study, we are focusing future whole lake 2,4-D treatments for Eurasian watermilfoil at target lake wide concentrations of 250-350 µg/L averaged throughout the first week of treatment. Concentrations of 2,4-D above 500 µg/L coupled with exposure times of multiple weeks resulted in decreased frequencies of occurrence of several native species. In small-scale treatments, herbicide concentrations 24 hours after treatment were well below the target concentrations due to fast dissipation of the herbicide off the treatment site. Researchers are compiling more treatments to determine what size treatment area is necessary for consistent results. Establishing guidelines for large and small scale treatments will help improve efficacy of target species while preventing damage to native aquatic plant communities. This report provides an update on the first years of the study and provides the basis for future research directions and guidance. DNR Science Services is preparing this report for publication which will provide the individual case studies as an important reference tool for managers.