The research has revealed how tiny amounts of environmental DNA (eDNA) released into water by great crested newts can be used to monitor the species. This can bring benefits for its conservation, and help protect great crested newts from major construction projects.
It has also revealed, for the first time, how great crested newt eDNA varies throughout the year in relation to population size and environmental factors.
Andrew Buxton and a team from the Durrell Institute of Conservation and Ecology (DICE) studied great crested newts on the Canterbury campus, where there are eight identical ponds.
Surveying the newts every fourteen days throughout the year, Andrew and his team mapped the amount of DNA in the water as it changed through the seasons in relation to the number of newts and their behaviour – from their arrival in March through their breeding season in May, until the start of hibernation in October. During breeding, the newts are very active and release a lot eggs, sperm and DNA into the water. This results in a peak in DNA towards the end of the breeding period, which may be the best time to take water samples to detect the species.
eDNA sampling can improve the effectiveness of surveys on sites scheduled for development. By finding rare species early in a development, there is less chance of delays than if they are found once it has started, saving time and money.
The great crested newt is protected under European law although it is not uncommon in the south-east of England, which is one of their strongholds in the UK. They have, however, suffered dramatic declines over the last 60 years, due to development and agricultural changes.
The team’s paper, entitled Seasonal variation in environmental DNA in relation to population size and environmental factors (Andrew S. Buxton, Jim J. Groombridge, Nurulhuda B. Zakaria & Richard A. Griffiths) was published in Scientific Reports on 10 April 2017.