Environmental DNA: The New Frontier of Aquatic Invasive Species Detection

Government agencies, non-profit organizations, and landowners need rapid and affordable monitoring protocols to detect aquatic invasive species. Environmental DNA (eDNA) is swiftly becoming an inexpensive, fast, and effective tool for invasive species detection. In an effort to inform monitoring protocols, we are working to improve eDNA detection and collection methods. We designed real-time PCR tests to detect eDNA from three invasive species: Eurasian watermilfoil (Myriophyllum spicatum), zebra mussels (Dreissena polymorphia), and quagga mussels (Dreissena rostriformis).  These sensitive tests detect DNA quantities similar to what is found in only 10-100 cells. We also compared two eDNA collection methods in lakes: a high-volume water filtration method, using a plankton tow net, and a traditional method, using cellulose nitrate filter paper.  In lakes, the high-volume collection method detected aquatic species more often than the traditional method did.

We applied these findings to monitoring protocols in northwestern Montana. We sampled 32 lakes using the high-volume collection method and tested each lake sample for Eurasian milfoil, zebra mussels, and quagga mussels. We successfully detected a known infestation of Eurasian milfoil in Beaver Lake, MT. As expected, no zebra or quagga mussels were detected in any samples.