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Floristic Diversity of Watercourses and Temporary Reservoirs of the Ostrovtsovsky Cluster of the Volga Regional Forest-Steppe State Natural Biospheric Reserve Impacted by the European Beaver’s Expansion

The paper is devoted to an important problem of modern ecology, namely, the reaction of native ecosystems to the activity of invader species, with the European beaver (Castor fiber L) as an example. This species transforms the environment as a result of its foraging and constructive activities. Higher vascular plants (macrophytes) in water bodies and streams are one of the basic components of biotopes. They serve as a limiting factor for the spread of such invasive species as C. fiber, because macrophytes determine the basis of this animal’s diet.

ON THE CASTOR FIBER (CASTORIDAE, MAMMALIA) ACTIVITY INFLUENCE ON THE ECOSYSTEM BIODIVERSITY OF SMALL RIVERS IN THE FOREST-STEPPE ZONE

Preliminary data on the Castor fiber activity influence on the ecosystem biodiversity of small rivers in three steppe clusters within the State Nature Reserve “Volga forest-steppe” were obtained. With zooplankton, amphibians and fish as examples, it was shown that after beaver-made ponds had appeared, the abundance of all these groups increased. In old ponds, the fish abundance decreases whilst the amphibian one continues to increase. In drained ponds, the zooplankton and amphibian abundance decreases while the fishes become more numerous, due to the appearance of better flowability.