Long-Term Observations over the Structure of Macrophyte Communities in Floodplain Water Bodies of the Chornobyl Exclusion Zone

Abstract

The study is based on long-term observations (1998-2021) over the species richness and cenotic activity of macrophytes of floodplain water bodies of the Chornobyl exclusion zone. During this period, the species composition of macrophytes of the studied water bodies remained almost unchanged. The lists of species found in 1998 differ from those registered in 2021 only by three species, including <i>Nymphaea alba, Trapa natans</i> (registered only since 2007), and <i>Utricularia minor</i> (found only in 1998, whereas in subsequent years was not observed at all). In the studied water bodies, macrophytes are not diverse in their species composition; their cenotic structure is simple, whereas overgrowing intensity of water surface is high. The presence of rare species of the boreal complex, including primarily <i>Hottonia palustris, Potamogeton acutifolius</i>, and <i>Callitriche cophocarpa</i>, makes these water bodies objects of protection and research. In 1998, a common feature of the vegetation cover of all studied floodplain water bodies was a predominance of macrophyte communities, in which the species of river and lake ecosystems, as well as indicator species of increased water logging processes, were registered. At the present time, natural structure of macrophyte communities of floodplain water bodies of the Prypyat River, which was deteriorated as a result of the construction of flood-protection hydraulic structures, is gradually recovered. The peculiarities of the distribution of macrophytes at the present time are indicative of the improvement of water exchange in floodplain water bodies. The chronic ionizing radiation influencing the biota of the studied water bodies for more than 30 years did not result in significant changes in the floristic and cenotic composition of macrophytes. Certain changes are conditioned by changes in hydrological and hydrochemical regime of the floodplain of the Prypyat River.