Ecomorphic analysis of plant communities with Ambrosia artemisiifolia L. in the urban ecosystem of Dnipro city

The relevance of the study is due to the growing problem of invasive plant species, in particular ragweed, which has become a dominant weed in many regions of Europe, including Ukraine. This species not only adapts to the conditions of urbanized areas, but also significantly changes the structure of the vegetation cover, which can lead to the loss of biodiversity of native plant species. In the city of Dnipro, where anthropogenic factors contribute to the spread of ragweed, it is important to know its impact on plant communities. Within the urban ecosystem of the city of Dnipro, 343 species of vascular plants belonging to 74 families were found on 685 surveyed plots. The phytocoenoses with Ambrosia artemisiifolia include 300 species from 71 families, while 274 species from 64 families were recorded in phytocoenoses without this species. The adventitious component of plant communities is 128 species (37.3%), of which a significant proportion (70%) are neophytes, mainly with a North American primary range, many of which have become naturalized. Among the most dangerous invasive species in phytocoenoses without ragweed are Polygonum aviculare (57.6%), Hordeum murinum (51.6%) and Chenopodium album (49.2%). The communities with the presence of ragweed are dominated by Erigeron annuus (62.5%), Elytrigia repens (53.7%) and Chenopodium album (49.6%). The presence of ragweed is associated with a decrease in the coverage of competitive species such as Polygonum aviculare and Poa angustifolia, which probably indicates its allopathic activity. The analysis showed that in phytocoenoses with Ambrosia artemisiifolia, the average number of species is 16.64 ± 0.59, which is higher than in communities without ragweed (11.16 ± 0.48). This increase is explained by the emergence of synanthropic species that adapt to the conditions created by the invasion. However, the increase in species diversity is a sign of ecological imbalance, which can lead to the dominance of ragweed and the transformation of natural communities. Plant communities with and without ragweed have a similar phytocoenotic and bioecomorphic structure, which indicates favorable ecological conditions for the spread of this species in the urban ecosystem of Dnipro. Competition between species can be an effective factor that restrains the further spread of ragweed. This emphasizes the prospects of using interspecific competition as a method of regulating the invasion of A. artemisiifolia.