EPA Research Partner Support Story: Environmental DNA (eDNA) for species inventory
Partners: Maryland Department of Natural Resources (MDDNR), West Virginia Division of Natural Resources (WVDNR), California Department of Fish and Wildlife (CADFW), California Department of Water Resources (CADWR), California State Water Reclamation Control Board (CASWRCB)
Challenge: Accurate and sensitive methods to detect hard-to-find endangered species
Resource: Environmental DNA (eDNA) for inventory and monitoring of imperiled species in collaboration with the U.S. Fish and Wildlife Service (USFWS) Pennsylvania Field Office, and the University of Kentucky Department of Forestry
Project Period: 2017 – Present
Conservation and management of endangered species require being able to locate populations and determine their distribution in the environment. However, classical monitoring approaches may overlook or underestimate species presence. Because living organisms constantly shed DNA into the environment, environmental DNA (eDNA) may offer an efficient, more sensitive, and non-invasive solution for detecting endangered species at low abundances and can be readily obtained from environmental samples (e.g., water, soil) instead of thru capture of whole organisms. Because each organism’s DNA contains a unique genetic code, eDNA can be used for precise taxonomic identification. The non-invasive nature of eDNA surveillance reduces stress, harm, and spread of disease to the species of interest.
“The development and validation of the eDNA methodology will profoundly change how aquatic populations are monitored and significantly improve the ability to conserve and recover rare aquatic species.” – WVDNR Wildlife Diversity Biologist Janet Clayton
To provide support to various state agencies and in collaboration with EPA Region 3 (Mid-Atlantic), EPA Region 9 (Pacific Southwest), the U.S. Fish and Wildlife Service (USFWS) Pennsylvania Field Office, and the University of Kentucky Department of Forestry, ORD scientist developed eDNA tools and assessed the capability of eDNA to determine distribution and relative abundance of species of concern. This included the federally-listed dwarf wedgemussel (Alasmidonta heterodon) within the Chesapeake and Potomac drainage basins in Maryland. Multiple ongoing research are also targeting various salamander species in KY streams, several imperiled freshwater mussels (Northern riffleshell, Snuffbox, Brook and Green floaters) in WV, PA, and MD, and other listed species in the Sacramento river (Delta smelt) and Vernal pools (Fairy shrimp) in the Central Valley, CA.
These studies demonstrate how eDNA can be an effective tool for determining species occupancy at low abundances or limited biomass. For example, in our dwarf wedgemussel eDNA was detected in water samples from all Maryland streams known to support the species including streams with relatively low abundances. Innovative techniques like eDNA surveillance can be incorporated into the species conservation management toolbox as an efficient and cost-effective means for state agencies to inventory and monitor imperiled species occupancy, to guide more localized traditional monitoring efforts, and to inform habitat suitability studies for species reintroduction programs.