Pool frogs in England

Northern pool frogs Pelophylax lessonae have an intriguing history in England (see www.arc-trust.org/pool-frog). Long thought to be an import from the continent and therefore classed as an “alien” species, this situation was re-evaluated in the late 20th century. Sadly, evidence that pool frogs were in fact native to England only emerged as the last known population, at Thompson Common, died out. A project brought the animals back to a confidential location in Norfolk in 2005, as part of a trial reintroduction using pool frogs captured in Sweden under special permission. Genetic analysis showed that English pool frogs were most closely related to Scandinavian frogs, hence the name northern pool frog. This variant of the pool frog is rare at a European level. The first reintroduced population has established and grown gradually, in one of the very few projects to reintroduce a nationally extinct species.

The release at Thompson Common in August 2015

Using frogs taken from the other Norfolk site and reared on in captivity, Amphibian and Reptile Conservation staff are releasing northern pool frogs at Thompson Common. This site is managed by the Norfolk Wildlife Trust, and the two organisations have worked together in preparing the site for the frogs. Before any reintroduction, it’s crucial to address the original causes of extinction, and at Thompson Common these are thought to have been issues with water level and habitat management. Therefore in recent years a huge effort has gone into addressing water levels and restoring habitat to create the specific habitats that northern pool frogs need. These measures are also benefitting a wide range of other species. Download our leaflet 'Re-introducing the northern pool frog to NWT Thompson Common, Norfolk'.

Project partners

Norfolk Wildlife Trust (www.norfolkwildlifetrust.org.uk) and Amphibian and Reptile Conservation are the project leaders. Natural England has kindly assisted with the project, as have a range of other organisations and volunteers. Shorelands Wildlife Gardens (www.shorelands.org.uk) have assisted with rearing tadpoles. The pool frog project is part of the Breaking New Ground Landscape Partnership Scheme, supported by the Heritage Lottery Fund. Breaking New Ground aims to tell the story of The Brecks and reconnect communities to the landscape. See www.breakingnewground.org.ukfor more information.