Prokopuk M. Invasions of macrophytes in the Middle Dnipro Region.

The thesis is devoted the analysis of the genesis of penetration and the regional features of invasion alien species of macrophytes in aquatic ecosystem of the Middle Dnipro Region. It has been inventoried an alien species of higher aquatic plants of the Middle Dnipro Region. It has been established modern features of dispersal and biotopic confinement of macrophytes in aquatic ecosystem of research region. It has been investigated regional features of cenology, ecology, phenotypic variability of model species and it’s production indicators. It has been characterized specifics of invasion strategy. It has been evaluated potential environmental impact of alien macrophytes on natural ecosystems and it is developed recommendation of assessments possible consequence and invasive potential. On the territory of the Middle Dnipro are spreaded 11 alien species of higher aquatic plants, that made near 15% of the lists of hydrophilic flora in the region. It has been prefered the reservoirs with high trophic status (from meso-eutrophic to eutrophic). Current change of secondary area of Acorus calamus, Elodea canadensis and Vallisneria spiralis are not not observed, invasion on these plants tooked place more than 100 years ago and they are completely naturalized. Eight species, invasion of which are not more than 20-50 years (Azolla caroliniana, Egeria densa, Elodea nuttallii, Lemna turionifera, Phragmites altissimus, Pistia stratiotes, Zizania latifolia, Typha laxmannii) can be considered as capable of penetrating into new habitats. In the Middle Dnipro Region the cenopopulations of alien aquatic plants exhibited a wide morphometric variability (the range of values varies from 20 to 100%), which indicates about the plasticity of species and the passage of the processes of active adaptation. The increase of the nutrient of the reservoirs causes a decrease in the production indicators of cenopopulations of Elodea: high values of phytomass are formed under conditions of moderate content of nitrogen compounds of mineral, less water temperature; impact the content of phosphates in the water on the production values are lower. Assessment of the invasive potential of alien aquatic plants in the Middle Dnipro showed that Elodea сanadensis, Еlodea nuttallii, Azolla caroliniana and Pistia stratiotes – these are species that can be have a high invasive potential. Other species can be considered alarming alien species.