Biological pollution of the flora of Volyn’ Polissya in Ukraine by alien plants

This study aimed to analyse biological pollution of the native flora of Volyn’ Polissya in Ukraine by alien plant species. According to the research results, 364 alien plants belonging to 228 genera and 68 families were identified in the spontaneous flora of Volyn’ Polissya. The spectrum of the most species-rich families of the alien fraction of the region’s flora includes Asteraceae, Brassicaceae, Poaceae, Rosaceae, Chenopodiaceae, Fabaceae, Lamiaceae, Solanaceae, Caryophyllaceae. As a result of the phytopollution, at least 16 families were included in the region’s flora. Four species currently in a stage of expansion were identified (Reynoutria japonica, Impatiens parviflora, Echinocystis lobata, Bidens frondosa). By origin, the species of the alien fraction of the region’s flora are dominated by the immigrants from the Mediterranean, Iranian-Turan and Atlantic-North American floristic regions. Over the past 30–50 years, at least 80 new species of alien plants have been introduced into the territory of Volyn’ Polissya. Over the past 5–7 years, the speed of the spread and naturalisation rate of species such as Quercus rubra, Asclepias syriaca, Parthenocissus quinquefolia, Prunus cerasifera, Hippophae rhamnoides, Oenothera biennis has increased. These species intensively invade the native plant communities. Phytopollution of Volyn’ Polissya is promoted by the migration of alien species from agricultural lands and escaping from cultivation. This process is also facilitated by urbanisation and the development of transport infrastructure.