Structure and dynamics of the alien component of the urban flora of Uman (Cherkasy Oblast) over two centuries

Abstract

Aims. To determine the taxonomic composition, current structure, and long-term dynamics of the alien fraction of the urban flora of Uman City. Methods. The study was based on a critical review of literature sources, herbarium collections (KW, KWHA, SOF, UM, UPU), and original field observations conducted in 2001–2025.
Modern approaches to the analysis of taxonomic, geographical, and biomorphological structures of the flora were applied, along with the calculation of the index of anthropophytization (IAn). Results. It was established that the urban flora of Uman comprises 1,144 vascular plant taxa, of which 417 (36.45%) are alien. These belong to 262 genera and 69 families, with Asteraceae, Brassicaceae, Poaceae, Amaranthaceae, and Fabaceae as leading families. The geographical structure of the alien fraction is dominated by taxa of Asian (29.8%), Mediterranean (26.5%), and American (17.8%) origin. In the biomorphological spectrum, annual herbs (51.3%) and therophytes (51.7%) prevail. By immigration pathway, the majority of alien species are ergasiophygophytes (escapees from cultivation) — 51.9%. A steady increase in the alien component was observed: by 1900, 215 alien taxa were known
(IAn — 22.9%); by 2000, 300 (IAn — 29.2%); and by 2025, 417 (IAn — 36.45%). The high level of alien enrichment was driven by both historical processes of agriculture and plant introduction and by contemporary anthropogenic pressure. A significant role of the National Dendrological Park “Sofiyivka” and the Botanical Nursery of Uman National University as centers of naturalization of numerous ergasiophytes was revealed. In total, 52 invasive alien plants were recorded in the urban flora, including Acer negundo, Solidago canadensis, Helianthus tuberosus, and Ulmus pumila. Conclusions. The urban flora of Uman is characterized by a remarkable richness of its alien fraction. The results highlight its substantial contribution to the alien flora of the Ukraine as a whole and emphasize the necessity of further monitoring.