Distribution of Тrifolium rubens in Ukraine and the current state of its populations in Zakarpattia

Trifolium rubens is a Central European forest-steppe plant species reaching its eastern distribution limit in Ukraine and listed in the Red Book of Ukraine (2009).Our study was carried out in 2016–2020 and aimed to analyze the distribution of T. rubens in Ukraine, to identify the composition of phytocoenoses with T. rubens, and to evaluate the current state of its populations in the Zakarpattia region of Ukraine. The distribution of this species was analyzed based on data obtained from the field surveys, literature, online resources, and herbaria. In total, 78 localities of T. rubens were analyzed. Trifolium rubens was found to be distributed in Zakarpattia, Lviv, Ivano-Frankivsk, Ternopil, Rivne, Khmelnytskyi, Chernivtsi, and Vinnytsia regions of Ukraine. Two of these regions (Khmelnytskyi and Chernivtsi) were not mentioned before in the Red Book of Ukraine. The presence of T. rubens in Volyn, Zhytomyr, Cherkasy, and Kyiv regions is doubtful and not confirmed by recent data. Most localities of this species are known from Zakarpattia and Lviv regions.Three new localities were found in the Beregovo district of the Zakarpattia region in the foothills of the Volcanic Carpathians. The floristic compositions of the plant communities and ontogenetic structure of T. rubens populations in Beregovo and Mukachevo districts of the Zakarpattia region were investigated. Investigated populations are isolated with a dispersed disposition of plants on large areas. Trifolium rubens occurs here in meadow-steppe and meadow areas, on hillsides, and also participate in mesoxerophilous secondary (semi-natural) shrub communities in anthropogenically transformed areas. Often such populations are situated along pathways, on forest edges and fallow lands, and associated with ecotones of Trifolio-Geranietea sanguinei class. All studied populations were incomplete with the domination of generative shoots.