Podshivalina V. N. RussiaCheboksaryNature Reserve «Prisurskiy», 9 Lesnoy posyolok, Cheboksary 428034, Russiaosipovv@mail.ru Author's articles ON THE CASTOR FIBER (CASTORIDAE, MAMMALIA) ACTIVITY INFLUENCE ON THE ECOSYSTEM BIODIVERSITY OF SMALL RIVERS IN THE FOREST-STEPPE ZONE