News

Detecting Great Crested Newt using DNA

New methods for establishing the presence or absence of great crested newts (GCN) (Triturus cristatus) from fragments of environmental GCN DNA (eDNA) in waterbodies appear to be a great breakthrough in detection. GCN have a bad press where development is concerned and they are often blamed for causing delays in the planning process because of the lengthy survey effort required under the guidelines.

Here at Penny Anderson Associates we are currently looking into how this new technique might impact on how we carry out GCN surveys in the future. As part of this process our GCN surveyors are being made familiar with the new technique and the survey methodologies required to carry out eDNA sampling.

Traditionally four survey visits are required between March and June to establish GCN presence or absence. Only a single visit to a waterbody is required for eDNA testing within a ten-week period between mid-April and late June.

The new methods can detect the presence of GCN eDNA between 7 and 21 days after the newts have used a waterbody, depending on weather and pond conditions. DNA in sediments can persist several years and therefore sediment residues need to be avoided in samples. Detection rates using eDNA (99%) are also higher than the traditional four-survey methods (95%) in establishing the presence of GCN in a waterbody.

Using eDNA to determine presence or absence should be quicker and help prevent delays in planning. However, if the eDNA results show GCN to be present Natural England still require a population size class (PSC) to be established in order to inform the level of mitigation required for a European Protected Species (EPS) Development Licence.

Herein lies the predicament. In order to establish a PSC, six surveys are needed between March and June, with at least three of these surveys carried out between mid-April and mid-May. As eDNA sampling can not be reliably undertaken until mid-April, if GCN are confirmed there may not be enough time to fulfil Natural England’s guidelines for establishing a PSC.

As yet we do not know how quickly the laboratories will be able to turn around the eDNA analysis. Currently it is understood that samples may take several weeks to analyse meaning that results are unlikely to provide enough time for PSC surveys to be carried out in the current newt season. If, in the future, samples can be analysed in a couple of weeks, it is still unlikely that PSC surveys would be able to commence before the beginning of May, which does not allow enough time to fit in three appropriately spaced out surveys between mid-April and mid-May.

Will developers want to risk eDNA analysis indicating GCN presence at such a late date and potentially delay the planning application until the following year? The chances are they will still opt for the four traditional surveys and if GCN are found undertake the additional two surveys to establish the PSC. Natural England do however advise that where eDNA tests show the presence of GCN and PSC assessment is required, careful forward planning would be required.

One option for developers may be to initiate traditional GCN surveys in March and to combine visit two or three with eDNA testing. Should a negative eDNA result be obtained the remaining surveys would not be necessary. If there is a positive result the remaining three or four surveys would be needed.

Where eDNA methods should prove a distinct improvement on the present situation is on large projects that traditionally have long lead times, e.g. pipelines, major highways, airport expansion projects etc. Under these circumstances surveyors would be able to carry out eDNA surveys a year in advance to scope in or out, large numbers of waterbodies with potentially considerable savings to the developer. The eDNA approach will also be of use for temporary and low impact developments that may only require presence or absence surveys.

Natural England states that no survey licence is required to take the water samples. However, when using this technique to support a licence application Natural England will only accept this new survey technique if samples are collected by a suitably trained and experienced licensed GCN surveyor.

What is clear is that ecological consultancies need trained staff familiar with the new methodology. PAA is at the ready.

PAA offer a full range of consultant expertise on great crested newt survey and mitigation, and other protected species – please contact us for more information, or feel free to download one of our relevant fliers below:

Great Crested Newt & Development
Animals – Protected Species & Development
Environmental Impact Assessment
Environmental Method Statements & Ecological Clerk Of Works