The contemporary distribution of the aquatic Tertiary relict plant species of the Bern Convention in eastern Polesye

In spite of modern trends in the development of the eastern Polesye flora, the relict have been preserved in the aquatic ecotopes of Europe, including eastern Polesye. The paper highlights the peculiarities of the distribution in the region of three aquatic Tertiary relics preserved by the Bern Convention. According to the results of a field research, the degree of a modern rarity of the aquatic relict species in eastern Polesye was established, in particular, a very rare species (Aldrovanda vesiculosa), a moderately rare species (Trapa natans) and a relatively rare species (Salvinia natans). The current distribution of these relict species in the region has been positively affected by the increase in the values of maximum temperatures and isotherms of the summer months. A negative impact is made by the abrupt changes in the hydrological regime and the growth of anthropogenic eutrophication of reservoirs. Aldrovanda vesiculosa eliminates with minor changes in living conditions; Salvinia natans is the most tolerant to anthropogenic factors, but shows annual fluctuations in numbers; Trapa natans is stable distributed and has a tendency to expanding of its populations. The relics are the dominants of the Salvinio–Spirodeletum (polyrrhizae), Lemno Utricularietum vulgaris, Spirodelo–Aldrovandetum vesiculosae, Trapetum natantis and Trapо–Nymphoidetum (peltatae) communities