Typha laxmannii (Typhaceae) in Ukraine: current distribution, еcological and coenotic pecularities, invasiveness

Here, we present history and modern distribution of Typha laxmannii in Ukraine, its ecological and phytocoenotic peculiarities. It is a perennial herbaceous plant, alien species of Asian origin which is currently spreading in the country. For the first time in the flora of Ukraine T. laxmannii (under the name T. stenophylla) was recorded in 1902 in the south of Ukraine (Kherson Oblast). The species is distributed almost throughout Ukraine, but with a majority of records in the central and western parts of Ukraine. The association Typhetum laxmannii formed by this species is common for Ukraine. Depending on the ecological and geographical conditions and floristic composition, 3 following variants in this association were identified: var. typica, var. T. latifola, and var. Schoenoplectus lacustris. Phytocoenoses of this association are distributed almost throughout the whole territory of Ukraine, but the ecological optimum of the species is observed in the South of the country, in the steppe zone, on slightly saline, well-watered substrates. Based on studies conducted in Zhytomyr Oblast in 1995–2021, the expansion rate of T. laxmannii was observed – from the South to the North – in average 16.6 ± 1.09 km·year⁻¹. From the sites of the primary penetration of the species into the region (Forest-Steppe zone), the expansion rate of it toward to the North was significantly lower (7.7–9.0 km·year⁻¹) compared to that in the Forest zone – Ukrainian Polissia (23.4–31.9 km·year⁻¹).