2015-2018 eDNA survey results
The PondNet monitoring network for Great Crested Newts, is an annual survey of 131 randomly selected 1 km grid squares spread throughout England. The 380 ponds which are encompassed by this network, are surveyed by volunteers and project officers using eDNA (environmental DNA). The presence of Great Crested Newts is detected during laboratory analysis of a water sample, which is collected using a standardised methodology from each pond in May and June.
Thanks to funding from Defra, Natural England and the Heritage Lottery Fund, and with support from Amphibian and Reptile Conservation and the Amphibian and Reptile Groups, this is the first ever national eDNA survey WORLDWIDE!
We have now completed 4 years of survey (2015-2018), visiting the same ponds annually to build a picture of status and change. Whilst this is still a relatively short timescale, we can begin to report with greater certainty on the current status of Great Crested Newts in England.
The number of occupied 1km grid squares: We estimate that between 11-21% of 1 km grid squares in England are occupied by Great Crested Newts (95% confidence), and in the short term (over the four years of survey), this isn’t changing.
The number of occupied ponds: We estimate that between 7-22% of 1 km grid squares in England are occupied by Great Crested Newts (95% confidence), but there is no significant trend over the four years of survey, because pond occupancy by Great Crested Newts shows a great deal of variability between years.
The number of occupied ponds per square: In occupied squares, the number of occupied ponds per square has been consistent, at around 2 ponds per square on average for the last four years. The eDNA results tell us that Great Crested Newts are not able to occupy all the ponds available to them, because of unsuitable habitat, fish, etc. On average, Great Crested Newts occupied less than 50% of the ponds in the squares where they are found.
The results show that there is no significant change in the number of occupied squares, occupied ponds, or occupied ponds per square over the four years of survey 2015-2018. We would not expect to see significant change over short timescales, and are likely to be seeing lower occupancy than would have occurred historically (c.50 years ago).
You can read a detailed report on the finding over the first three years of survey 2015-2017, along with a summary of the 2018 results (below). We have also summarised the results from individual sites for the south, central and northern PondNet regions.