The beavers are back in town Mark Elliott/Devon Wildlife Trust

I have gone back in time to a landscape not seen in this part of the world for the best part of 500 years. All around me are signs of intensive engineering – not by humans, but by beavers.

Mark Elliott at the Devon Wildlife Trust is showing me round 2.8 hectares of wetland on the edge of Dartmoor, UK. In 2011 the trust released a pair of Eurasian beavers here. “They’re really busy at the moment,” he says.

Before the release, the area was a scrubby woodland with …