Anthropogenically disturbed communities can be a source of introduction of alien plants into less disturbed adjacent communities. The purpose of the work was to assess the degree of adventitization of forest communities of the Kalinovsky Forest Park (Yekaterinburg) near different sources of propagules of nonforest plants. 24 sample plots of 20×20 m were surveyed: on the borders with garden plots, on the borders with the railway, inside the forest park. It was found that the average number of alien species was 7 times greater near garden plots compared to other options. The cumulative richness of alien species near garden plots was also almost 5 times higher compared to other options.

Catastrophic forest fires in 2010 affected about half of the largely anthropogenically transformed territory of the Kerzhensky Nature Reserve. As a result of many years of research, it has been established that the flora of the part of the reserve affected by fires includes at least 320 plant species and is distinguished by a smaller proportion of alien species than the flora of the entire reserve. Some species were recorded in areas affected by fires only in the first two years after the fire; several species found before 2010 were not recorded after the fire. As much as 15 species are reported to be potentially invasive.

Information is provided on the settlement of a new invasive species Chondrilla laticoronata Leonova (Asteraceae) in the Astrakhan region and Stavropol Territory. It is assumed that the species settlement takes place along the roads and railways from Western Kazakhstan. The biological features related with the biogeographical and phylogenetic patterns of the genesis and dispersal of C. laticoronata, the uniqueness of karyotypic polymorphism and genome size, as well as morphological variability and molecular genetic polymorphism in its populations are discussed.

The species composition of the floras of four insular forests was identified and alien fractions were analyzed. In the Krasnosamarsky pine forest the share of alien species is 12 %, in the Buzuluksky pine forest it is 14 %, in the Khrenovsky pine forest it is 15 %, in the Usmansky pine forest it is 20 %. The proportion of monospecific families with alien taxa in the floras of pine forests located in the steppe zone (Buzuluksky and Krasnosamarsky) is two times lower than in the floras of pine forests in the forest-steppe zone (Usmansky and Khrenovsky). The proportion of monospecific genera represented by alien species varies from 17.6 % to 23.5 % relative to their total number in the floras and from 45.1 % to 51.4 % relative to genera of the alien fraction. The high percentage of monospecific genera in the alien fraction and calculations based on the indicator of autonomy of the flora development are indicative of allochthonous developmental pathway of the floras of Khrenovsky and Krasnosamarsky forests.

The article discusses the current level of species diversity, structural features and dynamics of the alien fraction of the Bryansk flora. 370 adventive plants have been registered. The analysis of the alien fraction of flora is carried out and conclusions about its dynamics are drawn. There is a significant increase in the share of ergasiophytes, and in terms of the degree of naturalization – that of colonophytes and agriophytes. Over the past 20 years, the phytocenotic amplitude and the rate of spread of many alien plants have expanded.

The study has shown reproductive peculiarities of species and forms of the genus Robinia L. for forecasting the risks of their use in artificial plantations, and the ranking by the status of their invasive activity was carried out. It is found that in the conditions of Volgograd region Robinia pseudoacacia f. pyramidalis (Pepin) Rehd. and R. pseudoacacia f. umbraculifera (DC.) Rehd. are not capable of blooming and bearing fruit, as well as of forming stable self-seeding artificial plantations. Recommendations on prevention of invasive activity of introduced species during planning and reconstruction of artificial plantations are given.

It was found that from the periphery to the center of S. sorbifolia thickets, the average length and diameter of the shoot increase by 2 times, the volume of one shoot by 8–9 times. In the periphery zones, young (1–5 years old) shoots absolutely predominate. In the center of the thickets, there is a significant proportion of cohorts older than 10 years, but shoots aged 1–5 years account for more than half of all shoots. In the center of the S. sorbifolia thickets, the abundance of plants of the grass-shrub layer is 10–20 times lower or more compared to the control forest community; the taxonomic richness of the grass-shrub layer is 6–8 times lower. The richness of taxa and the abundance of seedlings from the soil seed bank did not change depending on the abundance of S. sorbifolia. The average illumination intensity was as follows: 4±1 lx×10² under S. sorbifolia; 7±1 lx×10² under Rubus idaeus; 80±10 lx×10² under the canopy of urban pine forests. Dense thickets of S. sorbifolia intercept about 93 % of the light from the level falling on their crowns.

The species composition of alien plants found in the flora of 15 pine forest outliers in the Chelyabinsk region was analyzed. A total of 122 alien species from 36 families were identified in pine forest communities. According to the method of immigration, most alien plants in pine forests are xenophytes. Based on the time of introduction, all identified alien species are neophytes (euneophytes); according to the degree of naturalization, the largest group is epecophytes (72 species). It has been established that the alien component of the flora of forest outliers is most rich in species of the families Rosaceae, Asteraceae, Chenopodiaceae and Fabaceae. In all pine forests, 39 invasive plant species were identified, among which woody plants predominated (16 species), annual grasses were represented by 12 species. The majority of alien species originate from North America – 35 species, 28.7 %; Asian species account for 34 species, 27.9 %.

The features of the reproduction of invasive plants in the urban environments are considered using the example of the North American species Erigeron canadensis L. In stressful conditions of the city high plasticity of individuals of E. canadensis is observed with maximum growth and development rates, settling on railway embankments, therefrom spreading into urban ecotopes. As far as the plants growing in technogenic areas (ash dump) are concerned, they are characterized by decreased overall size, a significant lower photosynthetic activity and the contribution of individuals to reproduction lower by several times. The least stable indicator of E. canadensis reproduction along the urban gradient is the mass of generative organs (CV 98.5 %). The more stable parameter was reproductive effort (RE1), the coefficient of variation was 49.8 %. The broad response of morphometric parameters to changes in ecotopic conditions can be assessed as a mechanism for the adaptation of E. canadensis to conditions in the city.

Preliminary information on the composition of alien plant species found along railways in some cities of the Republic of Dagestan is presented. 35 species of 15 families have been identified. The largest number of species (30 or about 85 %) were found within the city of Makhachkala. For the first time, five new species were identified for the alien flora of Dagestan: Cenchrus longispinus (Hack.) Fernald, Caragana halodendron (Pall.) Dum. Cours., Euphorbia maculata L., Lycium chinense Mill. and Panicum capillare Mill. Widespread species are Ailanthus altissima (Mill.) Swingle, Amaranthus albus L., A. retroflexus L., Ambrosia artemisiifolia L., Erigeron canadensis L., Euphorbia davidii Subils, Gleditsia triacanthos L. and Xanthium orientale L. Most alien species (25 or more than 70 %) are of American origin. The main part of the species (23) was brought into the study area through accidental introduction.