Consequences of the introduction of the Russian red tree squirrel Sciurus vulgaris exalbidus (Pallas, 1778) to Omsk oblast.
In Omsk oblast, the red squirrel Sciurus vulgaris is represented by three chorological groups with different geographic and demographic characteristics. The first group lives in the southern taiga subzone and northern mixed and deciduous forests and represents an indigenous group of S. v. martensi. The second group is formed in the southern subzone of mixed forests as a result of the introduction in 1957-1960 of S. v. exalbidus into the territory of habitation of S. v. martensi and represents a hybrid group different from the aboriginal one in the ratio of native color morphs and population dynamics and density. The third group is formed in the central forest-steppe in artificial pine plantations as a result of the introduction in 1976-1984 of S. v. exalbidus into the free area; it is small with sparse density and a characteristic ratio of color morphs.