FREQUENCY AND DEGREE OF DOMINATION OF ALIEN AND NATIVE SPECIES IN SYNANTHROPIC PLANT COMMUNITIES OF THE SOUTH OF RUSSIA

Abstract

Despite the steady interest of biologists in the problem of invasions, the role of alien dominants in the formation of the vegetation cover of recipient regions has not yet been quantified. We compared the frequency and degree of dominance of alien and native plant species in nine sites of synanthropic vegetation in the vicinity of several settlements in the Republic of Adygea and the Krasnodar Territory (the Western Caucasus: the basins of the Belaya, Tuapse, and Agoy rivers; the Kuban-Azov Lowland). Within them, 1950 to 3683 (24847 in total) accounting plots of 1 m were established, on which the projective cover of the dominant species was estimated. The results showed that in the studied sites of synanthropic communities about 10% of the dominants identified were alien species. Compared to native dominants, they are characterized, on average (per species), by a slightly higher frequency of dominance and achievement of a coverage of more than 80% in most sites. At the same time, on average, for all sites, alien plant species dominate in 12% of the accounting plots (in different sites from 2 to 28%), and they reach coverages of more than 80% only on 2.9% of plots (0.04-7.7%). The species similarity between complexes of alien dominants in different sites is, on average, higher than the similarity of complexes of aboriginal dominants. This means that the strengthening of the positions of alien species leads to an increase in the homogeneity of synanthropic vegetation in southern Russia.