Adventive tree species in urban flora of Rostov-on-Don.
We presented the results of study of the adventive tree species in urban flora of Rostov-on-Don (Russia). The taxonomic and typological structure of these species was determined and their ecological properties were investigated. We identified 147 species of woody adventive plants in urban flora of Rostov-on-Don. From species diversity the families Rosaceae Juss. (55 species), Fabaceae Lindl. (29), Caprifoleaceae Juss. (8), Oleaceae Lindl. (7), Hydrangeaceae (5), Ranunculaceae (5) and Vitaceae (5) are the dominants. In order to prevent the growth of the diversity of woody ergaziophytes species it is necessary to consider not only their ecological and biological properties, but also the regional economic value and importance. The species of Amorpha, Clematis, Colutea, Crataegus, Swida are potentially dangerous and should be excluded from the introduction scope. It is necessary to withdraw the species that have a set of properties suitable for naturalization, but have no economic or scientific interest from the collections of the Botanical Garden. In this regard, the collecting of sterile samples and plant forms could be extremely important. Special attention should be paid to the selection of the plant sets in small towns and rural areas, which are the places of spreading of the adventive plants and are similar to natural coenosises.