Untitled research work

A century ago, overhunting had reduced Eurasian beaver Castor fiber populations to c. 1200 animals in scattered refugia from France to Mongolia. Reintroductions and natural spread have since restored beavers to wide areas of their original range. The population has more than tripled since the first modern estimate in 1998, to c. 1.5 million. Range and population size have never increased more rapidly than in the last 20 years, and further large increases can be expected. The largest recent range extensions have been in western and south-central Europe, southern Russia, and west and central Siberia, both from reintroductions and from natural spread. Populations are now re-established in all countries of the former European range except for Portugal, Italy, and the southern Balkans, and broadly across Siberia to Mongolia, with scattered populations farther east. There are populations of introduced North American beavers Castor canadensis in Finland and north-west Russia, and in the Russian Far East. Several other populations of this species have been removed, or become extinct.