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eDNA & Great Crested Newts

In March 2014 Defra published a study which evaluated the efficiency of using environmental DNA (eDNA) to detect populations of great crested newts (GCN) in ponds. The results of the study showed that this test can be more effective than conventional survey methods in detecting great crested newt presence, and Natural England has stated that it will accept eDNA results as evidence of presence or absence of GCN for licence applications.

This week Urban Edge Environmental carried out our first survey using this technique alongside associates from the Ecology Consultancy in Lewes. The surveys were required to inform a planning application by a school and were necessary to rule out the presence of great crested newts from ponds within the school grounds. Twenty water samples were gathered from each pond with great care being taken to avoid cross contamination. The samples were then sealed and sent off for laboratory analysis, while the ecologists indulged in a spot of freshwater species identification with a class carrying out some pond dipping.

Survey using eDNA represents an exciting step in the survey of GCN. Rather than four survey visits to establish presence or likely absence from a pond, this technique requires only one, which can be carried out from mid-April until the end of June. As a result the cost to clients is likely to be less than conventional survey, and presence/absence surveys for great crested newts can be carried out over a much shorter timeframe.

However, the main limitation of this technique is that it cannot assess the population size of GCN if they are present, and this is required information for any great crested newt mitigation licence application. To obtain population data, six surveys using conventional survey techniques are still required. For this reason it is recommended by Natural England that this technique is only used where there is sufficient lead-in time to complete population estimates if necessary.

As can be seen the development of this new survey technique will provide a very useful tool for ecologists and developers alike and seems likely to be used more frequently over the coming years, though of course as with any new technology there are complexities inherent in its use. If you have any questions regarding great crested newt surveys or how eDNA analysis could help your development then please get in touch