Introduced species of trees and shrubs used in landscaping of cities in the steppe zone are exposed to the combined negative impact of the ever-increasing load of various anthropogenic factors and unfavorable zonal natural and climatic conditions. In this regard, the assessment of the degree of plant resistance to unfavorable factors in the urban ecosystems of the steppe zone is a necessary condition for rationalizing the selection of the assortment and improving the condition of green spaces. This paper presents the results of the analysis of the vital state of 5509 representatives of 78 introduced species of trees and shrubs growing along the road and transport network in the territory with increased anthropogenic pressure. The age structure of plantings, as well as a number of biological and ecological characteristics of the species composition, are analyzed. The variation in the level of vitality in groups united by individual characteristics—taxonomic affiliation, geographical origin, morphobiological characteristics (habitus), growth rate and age of plants—is shown, and groups with the highest level of vitality are identified. As a result, a number of criteria are selected that can serve as indirect markers of plant adaptability to the ecological conditions of steppe zone cities when forming an assortment for landscaping. Using the examples of the features “plant height” and “plant age”, the species-specific reaction of plants is shown, expressed in the limitation of growth and development, as well as the reduction of life expectancy under conditions of increased anthropogenic and climatic loads. The data obtained can be used to adjust the species composition of urban trees and shrubs, optimize their ratio and spatial and functional placement, and thereby optimize the operational characteristics of green spaces and increase the duration of their use.

The taxonomic and ecological structure of an artificial set of species of spontaneous flora of the local landscape Feofaniya, distinguished by decorative features, is presented. Decorative perennials, with the exception of aquatic and coastal ones, number 147 species. They are considered taking into account the adaptive characteristics, as a potentially basic component of the regional assortment of ornamental plants for landscaping. In terms of taxonomic composition, the species belong to 100 genera from 38 families. A significant part of perennials is rare in ornamental gardening. Among the studied perennials, the rare fraction includes 13 species with international (four species), state (seven species), or regional (six species) conservation status. According to the results of bioecological analysis, the predominance of mesophytic (76 %), heliophytic (44 %), mesotrophic (82 %), and neutrophilic (65 %) species is shown. When considering the ecological affiliation, the studied species are united into 15 principal ecomorphological groups. The use of plants represented in such groups as the main assortment in the landscaping of the corresponding ecotopes is a prerequisite for the stability and durability of such artificial communities as flower arrangements. The proposed assortment ensures the creation of modern low-cost flower arrangements, as well as the preservation of the biodiversity of the local flora by expanding the cultigen range of these species.

The anthropogenic transformation of the steppe zone in the southern East European Plain has led to the destruction and catastrophic fragmentation of natural ecosystems. Due to the presence of highly fertile lands and the deposits of the Donetsk coal basin, up to 90% of the territory is occupied by agricultural and industrial activities, urban agglomerations, other settlements, and extensive transportation networks. The predominant use of introduced species in artificial plantings (within the city limits, the ratio of species to quantity is 7:3) leads to the widespread spread of alien species, further isolation of natural habitats, and their subsequent degradation. The problem of preserving natural ecosystems and restoring a stable balance in their functioning can be solved through the widespread introduction of native species into all types of plantings capable of serving as ecological corridors. In this regard, we analyzed the key characteristics of native tree and shrub species that determine their functional value. The results indicate that of the 85 native plant species, only two cannot be used because they carry pests and diseases dangerous to agricultural crops. The remaining 83 species are suitable for various planting types, based on a set of individual characteristics, and 29 of these are universal for all planting types. Outside urban ecosystems, these 83 native species can completely replace introduced species. Within urban ecosystems, the need for their combination remains. Despite a number of advantages identified in native species in conditions of anthropogenic pollution (relatively high viability, long lifespan, good resistance to mechanical stress), native species lack a number of categories of traits necessary for the more effective functioning of urban green infrastructure. Among them, there is an insufficient number of tall species (>25 m) and conifers, which are more effective in purifying and improving the health of the atmosphere, as well as beautifully flowering and generally highly decorative species necessary for recreational areas and other territories that, among other things, perform esthetic functions.