A 5-year study into the impact of beavers on the river Otter in Devon shows they have a largely positive impact.
Scientists from Exeter University say they deliver benefits for amphibians, wildfowl and water voles, as well as increasing the number of fish by 37% where they dam the river.
They are also a boon for humans, as they reduce the impact of floods and help clean the water, filtering and removing pollutants.
There may be some local costs, as downstream floods are avoided by the beavers causing water to be stored on small areas of farmland. The authors of the report say it will be important to support and compensate such landowners.