In recent years environmental DNA (eDNA) surveys for great crested newts have become a popular survey tool. Torc Ecology are able to offer this service in circumstances where it will be appropriate to your project.
Our great crested newt survey page provides a detailed explanation of what’s involved in an eDNA survey. In brief, this survey technique involves gathering water samples from a potential great crested newt breeding pond and then sending the samples to a laboratory where they will test the water to see if any DNA from great crested newts is present.
Advantages of eDNA
The main advantage of eDNA over more traditional aquatic newt surveys is that only one site visit is required. This compares to having to complete at least four survey visits to get the same information from aquatic surveys. This makes eDNA surveys generally much cheaper than aquatic surveys when only presence/absence is required.
Another advantage is that eDNA can be collected up until the end of June. This means it is possible to survey for great crested newts later in the year than it is using aquatic surveys.
Disadvantages of eDNA
The biggest disadvantage of eDNA is that this method can only tell you whether great crested newts are present or not. In some cases this is all the information you’ll need to design a mitigation strategy and complete an Ecological Impact Assessment or European Protected Species Licence. In which case, the eDNA survey is incredibly useful.
However, if your project is likely to have a significant ecological impact and great crested newts are determined to be present, Natural England require a population size class assessment of the pond(s), i.e. a determination of the numbers of great crested newt present. This involves completing six aquatic surveys in addition to the eDNA survey. Therefore in this scenario, carrying out an eDNA survey would have been more expensive than just having completed the aquatic surveys from the outset.
There are also timing constraints. eDNA cannot be gathered until mid-April at the earliest whereas aquatic surveys can be undertaken from mid-March. However, if a positive eDNA result is found then at least three of the six aquatic surveys have to be completed between mid-April and mid-May. Even with a rapid turnaround on the laboratory analysis, it may be difficult to complete the required surveys in such a narrow window.
Using eDNA
Every site is different and whilst an eDNA survey may be suitable for one project it may be unsuitable for another. Please contact us if you require a great crested newt survey and we will discuss the pro’s and con’s of using this survey technique on your site.
