In 2011 altogether 10 inhabited beaver lodges were recorded: of 3 at the coast both of Lielaksnīte and the Moricsala Island as well as 4 at the mainland coast of the Usma Lake within the Moricsala SNR (Sāmīte 2011).

The beaver has been exterminated in Latvia in the 19 th century. So, at the time of establishment of Moricsala SNR the species was not present there. Species was not recorded in 1970s during systematic vegetation studies (Laiviņa & Laiviņš 1980). Beavers reappeared in the area of nowadays Moricsala SNR in the 1980s, i.e. 30 years after the release of a few animals in the Baņģava River, which mouths into Usma Lake. They are descendants of the 5 pairs of beaver from the Voronezh SNR, which were released in three rivers in Latvia (also in Kroja and Slocene) in 1952 (Балодис 1990).