Dynamics of riverbank ephemeral plant communities in the Stryzhen’ river estuary (Chernihiv, Ukraine)

The authors investigated the dynamics of ephemeral plant communities in the Stryzhen’ river estuary (N51°29’17’’, E31°18’57’’; Chernihiv, Ukraine; Eastern Polesia) after exposure to stress factors. The study of plant communities was carried out with generally accepted geobotanical methods. Samples of soil and water were analysed (in laboratory) using colorimetric methods and stripping voltammetry. The research shows that edaphic and hydrological conditions in the riverside alluvial sediment near the Stryzhen’ river estuary have changed under the influence of meteorological factors (mainly rainfalls). These changes have induced vegetation succession. In the monitored area, we observed a decrease in the concentration of nitrate, an increase in ammonia nitrogen content, the accumulation of sulphates, phosphates and salts of Zn2+, Pb2+, Cu2+, which came from rainfall and melt water. The accumulation of heavy metal salts did not reduce the formation of plant communities. The prognosis of further vegetation changes in the monitored alluvial area has been made. An increase in the area of communities on rich, low salified soils (order Agrostietalia stoloniferae Oberdorfer in Oberdorfer et al. 1967) is anticipated. Locations of Crypsis schoenoides (L.) Lam. and Dichostylis micheliana (L.) Nees. were identified for the first time in the Chernihiv region. Diaspora of these plants arrived in the Stryzhen’ river estuary through hydrochory along the northwest migratory route and the upper river that originates near the border of Ukraine and Belarus