In spring 2014 Natural England (NE) confirmed the use of environmental DNA (eDNA) sampling as an acceptable methodology for determining the presence or likely absence of great crested newts (GCN). The process has subsequently been adopted by Natural Resources Wales (NRW).

Following the NE announcement Avian Ecology quickly adopted the new methodology, completing a large number of pond samples in the survey season and including some of the very first commercial surveys in Wales. We ensured all of our licensed surveyors were provided with full training in the sampling methodology and employed rigorous bio-security measures.

So what have we learned?

Well, eDNA certainly can be a rapid way of detecting GCN presence. It has genuine commercial benefits, particularly for smaller projects or ones with long timelines, but is not always the most cost efficient methodology for developers. It’s all about scale as the cost of eDNA sampling kits is on a ‘per pond’ basis and set by the supplier. Rough calculations indicate that once more than perhaps 6 ponds need to be surveyed, the eDNA methodology costs are approximately break-even with conventional methods (bottle trapping etc); fees are simply transferred from field personnel time to lab costs. Furthermore, some lab results in 2014 took up to 5 weeks to receive, so any time saved in the field was quickly lost again, although 2014 was the first year of a new process and it is anticpated this will reduce to around 2 weeks.

Developers should remain aware that eDNA is only suitable for confirming presence or likely absence, and not population level surveys required to inform a development EPS licence. If there is likely to be a substantial time lapse between the planning submission and development then eDNA is very effective to inform the planning application, but additional conventional surveys will currently be needed for EPS applications. It seems likely that, at some stage, eDNA will be considered suitable for licence applications too.

From a consultant’s perspective, we retain some doubts that samples taken only at the very end of the eDNA season (late June) will actually detect GCN. Research on the effectiveness of eDNA states that accurate detection is achievable for around 11 weeks, but the generally acknowledged peak period for GCN activity is mid April to mid May (conventional surveys must include this period). In 2014 we certainly received ‘negative’ test results from ponds where we fully expected GCN presence (based on previous knowledge of the same sites) – we intend to test this hypothesis in 2015 by running parallel surveys.

So eDNA is certainly an improvement in many cases, but not all. We will continue to offer eDNA and conventional surveys methods to our clients and adopt new guidance and methodologies as they emerge. Most importantly, we will always provide advice on the most efficient and cost-effective way forward for each individual project.

Please get in touch and we will happily provide you with project-specific advice.