These attractive little rodents are found all across Europe and Asia, as far as China. In the British Isles they seem to be mainly aquatic (as suggested by the species name amphibius) but on the Continent the same animal is a land vole (which is why Linnaeus named the genus Avicola = 'field dweller).
Across its range it is not at risk but in Britain it has declined and is a protected species. The main reasons for decline seem to be habitat loss and predation by American mink, descended from animal who escaped or were released from fur farms.
However conservation efforts seem to have made a difference and the population seems to have picked up to some extent, but they are still much less common than they pnce were.