Comparative Assessment of the Functional Efficiency of Arboriflora Species Composition in Urban Green Spaces

The article discusses the results of a comprehensive analysis of the ecological state and environment-stabilizing functions of the species composition of arboriflora in the urban planting structure. It’s based on a large amount of factual material obtained during the course of a long-term monitoring of Vladivostok’s urban greenery. A methodological substantiation has been developed for a comprehensive qualitative-quantitative assessment of species using the applied qualimetry techniques. An integral indicator, named the coefficient of the functional efficiency of the species (JFEC) was proposed as the main evaluation unit. It is a relative-quantitative magnitude of plants quality that characterises their functional efficiency and significance in urban ecosystems: prevalence in greenery planting, vitality, the ability for accumulation of the priority pollutant metals in the urban environment, their concentration relative to the local ecological background; the capability for accumulating metals from the soil. Comparative analysis of the functional efficiency of 80 species of trees and shrubs forming the urban greenery of Vladivostok on the basis of the proposed coefficient was carried out. Among the compared sample of plants, the JFEC decreases from 3.70 (Crataegus pinnatifida) to 1.13 (Malus mandshurica). This values measure up to 74 and 23% of the quality standard (QS), which corresponds to the ideal plant species. The groups of species of different functional significance in the urban green spaces structure have been identified. The best efficiency in creating the comfortable environmental conditions in the city was demonstrated by species widespread in landscaping: Fraxinus mandshurica, Ulmus japonica, Betula platyphylla, Physocarpus opulifolia et al. They are characterized by the maximum participation in the formation of the urban greenery structure and a high ability to absorb the main pollutants of the urban environment. The JFEC of these species is within 3.26–2.61, which corresponds to 65–52% of the QS. In conclusion, author makes a suggestion on a rational use of species for the formation of a comfortable urban environment and introduction of the results into the practice of managing the urban green fund.