Environmental DNA (eDNA)

Science Center Objects

Environmental DNA (eDNA) is organismal DNA that can be found in the environment. Environmental DNA originates from cellular material shed by organisms (via skin, excrement, etc.) into aquatic or terrestrial environments that can be sampled and monitored using new molecular methods. Such methodology is important for the early detection of invasive species as well as the detection of rare and cryptic species.

A brown treesnake on frangipangi blossoms, by Bjorn Lardner, USGS.

A brown treesnake crawls on frangipangi blossoms in Guam. Bjorn Lardner, USGS.

Developing and Testing Methods for Extracting Environmental DNA from Soil Samples, with Applications to Detection of Brown Treesnakes - Principal Investigator - Sara Oyler-McCance

This project uses eDNA methods to determine whether the presence of brown treesnakes can be detected from soil samples. Thus far, eDNA methods have focused on aquatic habitats detecting DNA in water samples. The ability to amplify DNA from soil samples would allow greater geographic utility of these methods, and would be logistically preferable because water samples require extensive filtering, cold storage in the field, and high shipping costs for large volumes of water. Further, eDNA from soil could be a useful tool for early detection and rapid response activities for species such as brown treesnakes that rarely use aquatic habitats and which threaten to colonize previously snake-free islands.

Investigating Prey of Burmese Pythons using eDNA Methods - Principal Investigator - Sara Oyler-McCance

The highly invasive Burmese Python is having a devastating effect on the species native to southern Florida, particularly in the Florida Everglades. The goal of this project is to determine whether eDNA methods can be used to identify prey items eaten by Burmese Pythons.

Environmental DNA (eDNA) - Completed Research
An invasive Burmese python in the Everglades.

Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades, from the USGS Multimedia Gallery

Environmental DNA (eDNA) Sampling Improves Occurrence and Detection Estimates of Invasive Burmese Pythons and Other Constrictor Snakes in Florida​​​​​ -​​ Principal Investigator - Robert Reed

Low detection of invasive constrictors has hampered the estimation of occupancy and detection estimates needed for population management in southern Florida. We developed species-specific eDNA assays for the 5 constrictor snakes in Florida. We validated the python and boa constrictor assays using laboratory trials and tested all species in 21 field locations distributed in eight southern Florida regions. Burmese python eDNA was detected in 37 of 63 field sampling events; however, the other species were not detected. Although eDNA was heterogeneously distributed in the environment, occupancy models were able to provide the first estimates of detection probabilities, which were greater than 91%. The development of informative detection tools and eDNA occupancy models can improve conservation efforts in southern Florida and support more extensive studies of invasive constrictors. This research was in collaboration with the University of Florida.