The study was conducted as a part of the selection of the objects of phytomonitoring for the environmental assessment on the value of fluctuating asymmetry of bilateral morphological parameters. The territorial structure of flora of tree layer in Akhtubinsk and its local areas was determined as of 2013. The living conditions and species and quantitative composition of the tree layer of urban landscape were examined. The vital status of trees was assessed on a ten-point scale of the categories: good condition; satisfactory; weakened plants (Bukharina and Dvoeglazova 2010). The quantitative assessment of biodiversity of tree layer was made on the basis of conventional indices of individual dominance and dominating structures, as well as the method of multivariate statistical analysis. This is an objective method that has been used by other authors in a variety of the environmental studies for a long time, but it has not been actively used in the studies of the Astrakhan area vegetation yet. The results of the study make it possible to believe that the most appropriate indicator of tree vegetation for biomonitoring of intact floodplain, residential and recreational areas in the urban territory in the arid climate of the Volga-Akhtuba floodplain is the Chinese elm (Ulmus parvifolia Jacq.),as the most widespread, numerous and sensitive. It is noted that the tree vegetation cannot be a universal bioindicator of the urban environment in Akhtubinsk and its local areas by fluctuating asymmetry of bilateral morphological parameters.
Keywords: Akhtubinsk; Arid climate; Astrakhan region; Fluctuating asymmetry; Phytometer; Tree vegetation.