Bringing an English frog back from extinction

Before the 1990s, the loud chattering call of the northern pool frog could be heard across the wetlands of East England. But when it began to grow silent, no one really paid much attention - mainly because it had long been assumed that the frog (Pelophylax lessonae) was a species introduced from mainland Europe during Victorian times rather than a native - and therefore deemed to be of little conservation interest.

But when a raft of scientists in different disciplines actually began to investigate the frog, they discovered it to be a long-time native, right down to finding its bones along with those of Saxon-era humans from over a thousand years ago. Unfortunately, just as this realisation came to light, the northern pool frog croaked in England for the very last time in its last remaining hold-out in the wetlands of Norfolk. With habitat loss as a primary cause, the northern pool frog was declared extinct in England in 1995.

Dr Inga Zeisset from the University of Brighton taking pond samples in the field

Northern pool frog - image by Jim Foster for Amphibian and Reptile Conservation

Now award-winning filmmaker, biologist and artist Katie Garrett has made a short documentary film entitled Returning England's Forgotten Frog that tells the inspiring story of how Dr Zeisset and scientists from disciplines including history, bioacoustics, ecology and genetics came to realise their error over the northern pool frog - and then spent 25 years trying to put things right in a story picked up this week by The Times.

Having played a key role in initially proving the northern pool frog's native credentials by comparing DNA from other pool frog populations across Europe to that of the single last surviving Northern pool frog in Norfolk in the early 1990s (plus a few preserved museum specimens), Dr Zeisset (pictured above) has been part of the long and patient effort to bring the frog back to its old hopping grounds.

Using frogs from a closely related population in Scandinavia, the UK team obtained special permission to collect frogs from Sweden for release at a secret location in Norfolk in 2005. Ten years later, a second colony was created by moving frogs from the initial release location in Norfolk to the place where they were last seen in 1995, Thompson Common (a Norfolk Wildlife Trust reserve). The frogs can now be seen thriving at this reserve.

Dr Inga Zeisset, Senior Lecturer in the School of Applied Sciences at University of Brighton, said: "It's been an absolute privilege to have been involved in helping see the northern pool frog returned to the UK, playing a small - but key – role in a very big project in collaboration with the Amphibian and Reptile Conservation Trust."