Accumulation of heavy metals in birch and pine forest roadside phytocenoses in the south of Tyumen region

We conducted a complex investigation of anthropogenic roadside phytocoenoses. For the study, 8 plots (birch and pine forests) were selected, close to roads in the south of Tyumen region within the five administrative districts: Uporovsky, Zavodoukovsky, Yalutorovskiy, Yarkovsky, and Tobolsk. As a result of the studies, 75 species of vascular plants from 21 families were noted in the plant communities. It was found that the majority of the total projective cover of the plant communities was provided by synanthropic species. In the synanthropic fraction of the flora, 33 species belonging to 11 families were identified, those with the most species being: Scrophulariaceae, Compositeae, Rubiaceae, Poaceae, Fabaceae, Polygonaceae, Umbelliferae. The index of synanthropization of the flora of the studied phytocenoses is in the range from 43% to 64%. Among the identified pollutants accumulated in the phytocenoses, the group of heavy metals was identified (Cr, Cu, Ni, Pb, Sr, Zn). Needles of Pints sylvestris L. mainly accumulate Cr, Cu, Ni, Sr. The greatest concentration of Pb and Zn was found in the leaves of Betula pendula Roth. The content of other heavy metals in the leaves of Betula pendula Roth. during the growing season was relatively stable. Accumulation of heavy metals in the studied components of forest ecosystems can be displayed structurally: soil > leaves < phytomass (birch forests), soil < needles > phytomass (pine forests). Methodological approaches to conducting a complex of long-term observations of natural ecosystems have been formulated, substantiated and justified. To evaluate the absorption efficiency of heavy metals, the biological absorption coefficient was calculated. The obtained results can be used as a control in the study of migration and accumulation of heavy metals and for assessing the degree of anthropogenic load on phytocenoses of roadside ecosystems and predict the extent of probable changes in them. The forecast of the results will facilitate the elaboration of a necessary system of measures aimed at increasing the stability of plant communities.