2015 Great Crested Newt eDNA Results

2015 eDNA resultsHLF use

In spring and summer 2015 many of the PondNet team, including 112 volunteers plus staff, undertook an exciting new survey: to assess the status of England’s Great Crested Newt (GCN) population using environmental DNA (eDNA).

eDNA volunteer with kit and forms

We originally developed and trialled the GCN eDNA survey method in 2014 with the SpyGen laboratory, Amphibian and Reptile Conservation (ARC) and the Durrell Institute of Conservation and Ecology. In 2015, thanks to funding from Natural England and our Heritage Lottery Funded People Ponds and Water project and support from ARC and the Amphibian and Reptile Groups, we rolled out the first ever national eDNA survey WORLDWIDE!

The results, analysed by SpyGen in France, are now in – and they showed that:

  • PondNet volunteers are awesome and visited 316 ponds in 100 1km squares to collect 272 eDNA samples.
  • GCN ‘believed to be present’ squares. In the original database 4% of 1 km squares in England had records of GCN. Volunteers used eDNA to survey 50 of these squares and 34 returned a positive result (68%). Hence we did not record GCN in around a third of squares where we were expecting to find them. At some of these sites we had reports that the condition of the pond has declined significantly since the newts were last recorded, but some others are likely to have been erroneous original records for GCN.
  • GCN ‘Not previously recorded’ squares. In the original database 96% of 1 km squares had no previous records of GCN. Volunteers used eDNA to survey 50 of these squares and 12 (24%) returned a positive result.
  • Putting these two sets of data together gives us the best national estimate yet of how many 1km grid squares across England are occupied by GCN. The answer is around a quarter (26%).
  • We found out how many of the ponds in each occupied 1 km square are typically used by GCN: it’s an average of 55%. Resurveys of these same squares will provide one of the measures we’ll use to monitor GCN change in future years.
  • Across all ponds in England, around 13% of ponds in England are occupied by GCN. There are previous estimates from other surveys which give values that are similar (i.e. Swan & Oldham 1993 = 11%, Wilkinson & Arnell 2013 = 12%)
  • The eDNA survey found GCNs at sites where traditional methods would be unlikely to find them, such as ponds covered with duckweed or surrounded by dense scrub. This (i) shows how valuable eDNA techniques are when trying to find out if newts are present or absent in difficult sites, and (ii) extends knowledge about the sort of ponds that GCN occupy.
  • Many site managers were very pleased to have reliable information about the status of the newts on their sites.
  • We are excited (and relieved!) to have a high quality national dataset on GCN occupancy. This is year one and we’re looking forward to gathering data in subsequent years to show how the population is changing.
  • Feedback from volunteers has been overwhelmingly positive. People enjoyed taking part because it’s simple, it’s an exciting new technique, and they were doing ‘real science’.
  • We are phenomenally proud of our team, both volunteers and staff, for their commitment, enthusiasm, and all-round greatness.

Next steps

We are really pleased with the results, and how the survey ran. The good news is that with funding from the Heritage Lottery Fund, Natural England, Defra, Welsh Government, Valpak and Thames Water; we have enough eDNA kits to repeat the survey in 2016. We’ll get the results back in September.

Want to know more?

  • There’s a more detailed powerpoint presentation of the 2015 results here
  • Find out more about PondNet and how you can take part in future eDNA and pond surveys.
  • Read more about the research we did to develop the eDNA survey method.