From detecting pests to tracking threatened species or monitoring the overall health of our environment, eDNA is taking off as the technology to do it all. With the increased uptake comes an increased need for standardised methods. The results of eDNA studies need to provide robust environmental information. They should meet legal standards and be reliable for decision making.
What's possible with the technology?
eDNA methods capture, extract and analyse genetic material from environmental sources such as water, air and soil. DNA is shed into the environment by plants, animals and other organisms in the same way a human might leave traces of skin or hair at a crime scene.
eDNA methods provide a fast way to detect species without directly observing organisms. These methods can replace divers spending hours underwater observing fish. They can allow threatened lizards to be detected in their burrows without being handled. They can detect single species or multiple species. eDNA methods can also be deployed across large areas and in remote places. Samples can be collected using very simple equipment.
CSIRO postdoctoral researcher Dr Maarten De Brauwer helped develop the new guidelines for working with eDNA. He said the technology has a myriad of different uses.
“Research in applications of the technology is widespread and evolving at an incredible pace,” he said.
“Many people are familiar with eDNA surveys for marine fish. But the technology is being using in increasingly novel ways. Some examples include tracking the species present in airborne pollen, detecting deadly jellyfish that pose a risk to swimmers, and discovering undescribed species in subterranean ecosystems.
“eDNA has huge potential for environmental monitoring programs, ranging from simple projects designed to detect a single species, to monitoring programs designed to track the health of entire ecosystems over long periods of time."
Developing guidelines
eDNA methods are becoming a powerful tool in the fight to protect our environment and its diverse species. As a result, the methods need to be accurate, reliable, and trustworthy across their many different uses.
“Our new guidelines help solve the long-acknowledged lack of standardisation that has hindered the uptake of the technology somewhat,” Maarten said.
“Across the board, our goals are to ensure reproducibility of results. We also want to minimise false negative or false positive species detections. Consistent and reliable results make it easier to use eDNA monitoring results for decision-making.”
The new guidelines set minimum standards for taking a consistent and best-practice approach to eDNA testing. The protocol development guide covers everything from ethical considerations and experimental design to interpreting and communicating results. It also covers acknowledging First Nations Peoples. The test validation guidelines outline key steps for developing assays and validating species-specific testing and metabarcoding.
Using the guidelines
The guidelines are intended for governments, companies, researchers and any other groups that want to use eDNA in a consistent and high-quality manner.
“The guidelines are a foundation for researchers to build upon. We don’t want to restrict people. Instead, we want to encourage innovation and creativity in the field,” said Maarten.
“We will review and update the guidelines regularly. This will ensure the technology can continue to evolve to provide robust scientific evidence to support decision-making.”
The Australian Government Department of Agriculture, Fisheries and Forestry funded the Australian/New Zealand best practice guidelines for the use of eDNA/eRNA in biomonitoring. CSIRO and the University of Canberra developed the guidelines in collaboration with the eDNA community, including the Southern eDNA Society, experts, end-users and stakeholders.