Eurasian watermilfoil is a charismatic invasive species and has been found within the Lake Champlain Basin for well over 50 years. As such, they have spread widely and caused havoc throughout the basin; millions of dollars are spent annually on management and control. An important and often underappreciated aspect of management is the genetic ancestry of the organism, or population, in question. Newer genome-wide sequencing approaches have the resolution to expand upon current knowledge by using thousands of molecular markers, rather than a handful. This project generated genome-wide sequence data for hundreds of Eurasian watermilfoil from 30 waterbodies throughout the Lake Champlain Basin. Across all sampled Eurasian watermilfoil populations, over 100 unique clones (i.e., MLGs) were identified, demonstrating considerable genetic diversity despite the dominance of a small number of successful regional clones. One clone was detected in most waterbodies, making them the most widespread MLG identified during this project. In contrast, most other MLGs were private to individual waterbodies or found in only a few waterbodies, indicating that local genetic diversification is an important contributor to genetic ancestry. Further, we identified the Lake Hortonia area as a regional hotspot of genetic diversity, as Lake Hortonia contained many unique MLGs and consisted of multiple genetically distinct hybrids lineages. Further, our data suggest that Eurasian watermilfoil sexually reproduce at higher rates than is currently appreciated. Our findings demonstrate that Eurasian watermilfoil is considerably more genetically diverse than currently recognized, and multiple independent hybrid populations have been formed in a narrow geographic region. As hybrids and different clones can have variable responses to management practices, knowledge of their ancestry and follow up studies to understand their response to control should drive future Eurasian watermilfoil management.

Alex Sotola, Assistant Professor, SUNY Oneonta
Alex Sotola is an Assistant Professor in the Biology Department at SUNY Oneonta. He teaches classes in genetics, evolution, and bioinformatics, and works collaboratively with both undergraduate and graduate students on evolutionary genetics of fishes and plants, with a specific interest in hybridization and ecological genetics. This work was funded through the Lake Champlain Basin Program, and this presentation is the culmination of a two-year research project, led by master’s students Darian Paul and Caliegh Millette, with the assistance of many undergraduate researchers. Through his work, he wants to not only better understand the evolution of invasive species, but to also spread the word of how genetic projects should be incorporated into management and conservation work.