Overview of Environmental DNA Testing and Applications for Invasive and Endangered Species in Ontario

Environmental DNA detection is being used for complementary applications for invasive and endangered species in Ontario. Effective management of both groups requires sensitive detection of species occurrences, often at low abundances. In aquatic environments, the detection of rare or low-abundance species such as endangered taxa or early-stage invasive species is challenging at best, and discriminating between detection failure (null) versus true absence (zero) can be difficult. For both species categories, discriminating between detection failure and true absence has significant consequences for species and habitat management. Experimental eDNA trials to determine species occurrence in controlled and natural environments confirmed the taxonomic specificity and spatial, temporal, and quantitative sensitivity of eDNA detection. eDNA surveillance is currently being used in Ontario to map the spatial presence, absence, and seasonal habitat use of aquatic endangered fish species to support legislative protection of critical habitats, as well as to survey Ontario waters of Lake Erie for the potential occurrence of Asian carps (bighead, silver, and grass carp). These different applications and combined results confirm the utility of environmental DNA as a reliable method for species detection in freshwater systems, as well as its effectiveness for detecting both invasive and endangered freshwater species.