Building Confidence in eDNA Through Ecological Validation

25 September 2026

• Quality eDNA assessments involve more than generating a list of genetic matches.

• Ecological validation is our quality control protocol that adds an important layer of scrutiny to eDNA data.

• Join our quick 30-minute webinar to learn the processes that ensure confidence in your eDNA results. Register using link in article.

eDNA metabarcoding is transforming the way we survey biodiversity. By analysing DNA collected from environmental samples such as water, soil, or air, we can detect species and monitor biodiversity without needing to physically observe or capture them.

EnviroDNA was one of the first to bring eDNA solutions to industry in Australia. Spun out of academic roots, our approach to partnering with organisations across the country and globally is underpinned by scientifically robust methods and genuine advice.

As pioneers of eDNA research in Australia, we have a good idea of what constitutes quality eDNA results that enable confident decision-making. Put simply, eDNA results shouldn’t just be a list of species. Each detection should be considered, scrutinised and contextualised by people who understand both the technology and the ecology behind it.

That's why since 2016, we’ve implemented quality control measures to deliver confidence in every one of our results. Behind every eDNA detection is an internal process of data scientists and ecologists validating data against multiple lines of evidence to ensure the highest accuracy in your results. We refer to this process as ecological validation.
 

A real-world example

Recently, a client undertook an eDNA biodiversity assessment across several freshwater sites in regional waterways. Water samples were collected and analysed using metabarcoding to provide a picture of the species present.

Among the results was an unexpected detection: Atlantic salmon (Salmo salar). Given the location and survey context, the detection raised an obvious question. Why would Atlantic salmon DNA be present at these sites? We investigated further.

Through ecological validation process, we considered the broader environmental context and discovered that a salmon farm was relatively close to the sampling sites. This finding provided an explanation because it was likely that the salmon DNA had entered the waterways and was captured in the survey samples.

So, for the client, did we remove the detection from the report? No, the DNA was indeed detected in the sample, and the result was reported. However, we also provided the ecological context surrounding that detection, identified the potential source, and explained why the result should be interpreted with caution.
 

qPCR vs metabarcoding

Understanding the difference between eDNA analysis methods also helps explain why ecological validation is so important. Firstly, qPCR asks, "Is this species here?” A qPCR assay is designed specifically to detect a species of choice. The technique is sensitive and highly targeted.

Whereas metabarcoding asks, "What DNA is in this sample?” Rather than targeting one species, metabarcoding amplifies a barcode region shared across a broader group of organisms. The resulting sequences are compared against reference databases to generate a community list.

The benefit is breadth: a single analysis can provide information about many taxa. However, the trade-off is that each species detection is based on sequence matching and interpretation rather than a purpose-built assay for that individual species.

Metabarcoding eDNA data shouldn't simply be treated as a definitive list of everything physically present at a site. Instead, detections must be interpreted and validated against supporting evidence. Ecological validation serves as our quality control protocol that provides clients with meaningful ecological insights that support more confident decision-making.
 

From species lists to ecological evidence

Quality eDNA assessments involve more than generating a list of genetic matches. This process of ecological validation adds an important layer of scrutiny to eDNA data. The aim isn't to remove unexpected results because they don't fit expectations. What we do is investigate them, understand them and communicate the uncertainty or context clearly.

At EnviroDNA, we believe that eDNA results should encompass more than a list of species. That's why our experts, both in eDNA technology and ecology, scrutinise and contextualise survey findings through ecological validation. This approach provides validated eDNA result that can be used confidently to inform real-world management decisions.

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