The article focuses attention on analysis of new data regarding natural environment of Bakalsky population, attracting palynological data from Revda-2-1 fortified settlement and Revda-5 burial place in the Low Tobol basin (south-west sector of West Siberia). The new materials showed that in IV c. A.D. in the Low Tobol basin subject to prevalence being semi-open landscapes with massifs of birch forests and grass meadows. Presumably, those still bore traces of short-term episodes of steppe expansion, sporadically indicated at the turn of the eras. Approximately from V–VII cc. A.D., a vector of natural processes was changed — with a gradual change in the landscapes' look, manifested in the development of birch and pine forests in the Low Tobol basin. Further transformations, connected with intensification of swamping processes and occurrence of clean pine forests, were indicated starting from VIII c. A.D. Those changes served the vegetation response to decreasing continentality, as well as to reduction of frequency and duration of dry episodes in the Low Tobol basin, starting from the middle of the first millennium.