The current ecological and biological state of the adventive flora of the Sviyaga River basin

The paper provides information about the adventive fraction of the flora of the Sviyaga River basin, the right-hand tributary of the Volga, which flows administratively through the territory of two constituent entities of the Russian Federation - the Ulyanovsk Region and the Republic of Tatarstan. Currently, according to the results of perennial floristic studies, 341 species of vascular plants belonging to 216 genera and 64 families are assigned to the adventive fraction of flora. The distribution of adventive flora species by time, method of introduction and degree of naturalization is analyzed, which showed that the majority of the adventive fraction of flora penetrated into the studied area over the past 100 years due to the expansion of the transport network, intensive trade and active urbanization, while «aliens» occupied mostly disturbed habitats, often becoming elements integrated into natural communities of nature. In addition to the distribution of adventist species over time, the method of introduction and the degree of naturalization, an important indicator is the adaptation of these plants to the local conditions of the Sviyaga River Basin in natural ecosystems, which is reflected in their distribution by cenomorphs in the study area. As part of the adventive flora, 9 ecological-cenotic groups were identified, indicating, on the one hand, which communities are most favorable for naturalization in accordance with the life strategy, and on the other, it indicates their disturbance.