Invasive aquatic plants have large negative effects on ecosystem services (e.g., recreation, property values) and native plant biodiversity. In addition, they are very difficult to eradicate once they are well established in lakes and ponds. Yet invasive plants are often difficult to detect early because they can be very similar in shape and appearance to native species. Invasive species also may hybridize with native species, which can create unique genome combinations that are more invasive than the originally introduced exotic lineages.
The Molecular Ecology laboratory at AWRI, run by Dr. Ryan Thum, currently is conducting molecular genetic studies of aquatic plant invasions, focusing predominantly on invasions by water milfoils in the genus Myriophyllum (e.g., Eurasian water milfoil). Ryan's lab develops DNA-based identification methods to distinguish native and invasive species that are difficult to identify using morphological characters alone. They also use DNA fingerprinting methods to determine the degree of genetic admixture or hybridization among native and non-native lineages. Finally, Ryan and his students are integrating the molecular genetic data with geographic information to reconstruct the geographic origins of different species or lineages ('phylogeography').
The genetic information collected in the lab is then integrated with ecological studies and management practices. For example, the DNA identifications of aquatic plant species are used by several state government agencies to make decisions regarding whether or not a population of putative invasive species will be managed. Similarly, they use the phylogeographic data to identify the ecological factors that limit the distribution and abundance of an invasive species in its native range.