Assessment of the Functional State of Green Plantings and the Accumulation of Heavy Metals by Vegetation in Urban Green Areas for Various Purposes

This article is devoted to the ecological problem of effective urban landscaping and increasing the role of green plantings in stabilizing the environment. The paper summarizes the material on the complex bioecological assessment of functionally different urban green areas of Vladivostok. There are six types of urban plantings: ordinary plantings, squares, intraquarter gardening, old city public gardens, city parks, and intraurban recreational forests. The questions of the specificity of their species composition, conditions of growth, and the intensity of influencing anthropogenic press are considered. An almost fourfold increase of environmental stress in the following series is noted: city parks → intra-quarter gardening → intraurban recreational forests → old city public gardens → line plantings → squares. Most attention is paid to a comparative analysis of tree–shrub species and plantation accumulation of heavy metals: the main markers of technogenic pollution of the urban environment. The correlation regularities in the accumulation of heavy metals by plants in the conditions of Vladivostok urban ecosystems were found and a geochemical association of the main metal pollutants was established: Fe_4.1 Zn_2.0 Pb_1.9 Cu_1,4 Ni_1.3. It is shown that the intensity of heavy-metal transformation by green plantings increases 3 times in a ranked series: intraurban recreational forest → city parks → old city public gardens → intra-quarter gardening → squares → line plantings. On the basis of the research and earlier results, a complex assessment of the functional condition of city green plantings is performed. For a practical solution, the author offers the functional status index (IFS) of plantings as an integral indicator of the ecological condition of vegetation and soils of green plantings and their capability for heavy-metal transformation in the conditions of the urbanized environment. The high functional status of ordinary plantings and squares, caused mainly by the active accumulation of heavy metals by soils and plants, is noted. This index is one and a half times lower for old city gardens and intraurban recreational forests. In conclusion, the author recommends using the results in the organization of a rational system of urban landscaping and differentiated measures of care for plantations of various functional purposes.