In short
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Collecting an eDNA sample from a river.
eDNA in monitoring and research
Environmental DNA (eDNA) is a modern way to detect animals and plants by collecting traces of their genetic material (DNA) from the environment—like from water, soil, or air. Sources of DNA organisms leave behind include skin cells, faecal waste, or pollen.
Researchers collect eDNA to detect species’ presence without having to physically capture or observe the targeted species. Waterways are particularly suitable for eDNA sampling because DNA travels with water flows, allowing researchers to sample large areas from just one location.
Although eDNA is still a new tool in science, it's quickly becoming popular in research and monitoring projects—including those involving citizen scientists.
eDNA offers the potential to detect:
- species that are difficult, time-consuming or expensive to find; including species that are cryptic, rare, microscopic, nocturnal or found in hard-to-survey areas.
- multiple species from a single sample using a technique called metabarcoding
- early incursions of pest species or diseases to inform rapid management responses.
eDNA can work alongside or even replace traditional surveys methods in some cases. It’s often more cost-effective and can cover larger areas, but its suitability depends on what you're trying to find out.
Because collecting eDNA does not require special tools or training, it’s also a great fit for citizen science projects.
Limitations of eDNA
The field of eDNA sampling is still new and evolving. While many projects are requesting eDNA surveys to complement traditional survey methods (e.g. physical capture and observational sampling), there are still challenges with its use and the interpretation of results.
Uncertainties still exist in its use for detecting species’ presence, which may limit its value in some cases. Furthermore, eDNA technology cannot yet be used to reliably measure the relative abundance or demography of species at sites, meaning that it is inappropriate to use in many research and monitoring contexts.
eDNA is only as reliable as the methods used to collect and analyse it. Combining eDNA with traditional survey methods can aid the interpretation of eDNA results. To get accurate results, we need consistent field and lab protocols. Implementation of survey standards will improve data quality, reduce errors, and build confidence in eDNA findings.
There are many current gaps in knowledge regarding:
- how biological and physical factors affect detection probabilities
- how survey effectiveness is influenced by species’ characteristics
- best practices for survey design, quality control and assurance measures.
What we are doing
ARI has working with eDNA since 2018 in various environmental research contexts, especially in aquatic ecosystems. ARI has led:
- Detecting rare and pest species – using eDNA to find threatened fish, mussels, amphibians, spotted-tail quolls and invasive species (for example deer and willow).
- Designing survey methods – creating reliable eDNA study designs.
- Reviewing data – checking large eDNA datasets for accuracy, including spotting false positives and negatives.
- Studying uncertainty – reviewing research on the limits of eDNA, especially for freshwater species.
- Improving techniques – developing better ways to collect and analyse eDNA, including tests for new species in Victoria.
- Rapid in-field testing – creating eDNA tests that give quick results in the field using new technology.
- Validation studies – comparing eDNA results with traditional survey methods.
- Exploring new uses – trialling detection of aquatic plants with eDNA.
Using a syringe to collect an eDNA sample from a crayfish burrow.
How we can help
ARI offers expert support to guide the effective and appropriate use of eDNA in research and monitoring across Victoria. Our services include:
- Project guidance – expert advice on how to best use eDNA to meet your project goals.
- Data review – assessing and interpreting existing eDNA datasets to ensure accurate and meaningful results.
- Project integration – identifying how eDNA can be incorporated into new or existing monitoring and research programs.
- Filling knowledge gaps – delivering targeted research to improve confidence in eDNA methods and results.
- Technique development – developing and refining methods for collecting and analysing eDNA samples.
- Custom assay design – creating eDNA tests for species that are yet to be studied using eDNA methods.
Taking eDNA water sample with filter - photo by Tarmo Raadik.
More information
For further information about ARI’s eDNA expertise contact research.ari@deeca.vic.gov.au
Page last updated: 08/08/25