Alien species of mammals and their impact on natural ecosystems in the biosphere reserves of Russia.

The paper analyses the results of a survey of 37 Russian biosphere reserves using questionnaires concerning the presence of alien species of mammals, their pathways of penetration, and their impacts on protected ecosystems. The penetration of alien mammals into terrestrial ecosystems of Russia is extensive, both in places with maximum human environmental impact (inhabited areas and agricultural lands) and in biosphere reserves with minimal human impact. There are 62 mammal species registered as alien in Russian ecosystems and they account for 22% of the terrestrial mammal fauna of Russia. The percentage of alien species in biosphere reserves is 32.6% at most. In most regions, Castor fiber, Ondatra zibethicus, Nyctereutes procyonoides, Canis familiaris, Neovison vison and Sus scrofa are very dangerous, and both Castor fiber and Sus scrofa can have environment-forming impacts.