Earlier this month ARC hosted a visit from Swedish pool frog expert, Per Sjögren-Gulve. In the 1980s, Per completed his PhD study at Uppsala University, Sweden, on the pool frog, and he has been involved in the research and conservation of the species ever since. 

Swedish pool frogs are part of the genetically distinct northern form of the species, which includes frogs that used to live in England.  After the pool frog became extinct in England in the 1990's, it was reintroduced by importing frogs from Sweden in 2005.

Per's trip, which coincidentally coincided with World Frog Day 2024, included visits to the two sites at which northern pool frogs have been reintroduced to England. Not so much to see how the Swedish frogs are getting on, but rather to inspect and advise on the habitat in their new homes. 

Per commented:

 I am happy to see how the sites have been restored and the plans for the future – and I guess the pool frogs are too!

One of the sites visited was Thompson Common, where Norfolk Wildlife Trust manages this nationally important pond site and is currently working with ARC and the Woodland Trust on the Pool Frogs and Pingos project. The last known colony of English northern pool frogs was at Thompson Common. Conditions are perfect, thanks to the reserve’s 400 prehistoric ‘pingo ponds’ – glacial compressions formed in the last Ice Age. The soil beneath is nutrient-rich, and they’re teeming with life: dragonflies, damselflies, butterflies, beetles. Laser scans suggest there are at least ten pingos on Woodland Trust land, waiting to be revived. The project is expanding the habitat available to pool frogs by re-excavating and restoring ‘ghost’ pingos – those that have been infilled in the recent past. 

ARC project manager John Baker commented:

We hope to create a network of connected pool frog populations.  Such ‘metapopulations’ are more robust than isolated populations... I first learned about the importance of metapopulations at the first World Congress of Herpetology back in 1989 – in a presentation given by Per Sjögren-Gulve!  Thirty-five year later it’s nice to finally meet him in the field and talk about pool frogs!

ARC are pleased to say that there will be further investigations and habitat management following Per’s recommendations.

Photo credits: Anette Lindberg and Jim Foster