Spatial Dynamics and Interrelations of Contour Algal Communities in the Upper Section of the Kaniv Reservoir (Dnieper River, Ukraine)

The paper deals with spatial dynamics of microphytobenthos and phytoepiphyton in the localities with different degree of connectivity within the upper section of the Kaniv Reservoir. The stochastic factors (species migrations and exchange) have been proven to make a significant effect upon the local communities' species composition and abundance, which can be considered as a metacommunity. Potential paths of species exchange within the metacommunity have been revealed: along the vertical axis, in the horizontal plane and in the three-dimensional space. High degree of similarity of contour algal communities in the "isolated" water body and other localities in summer 2023 was explained by abnormally high water level in spring, that caused temporary hydrological connection between the water body and the main river channel, and thus exchange of species among the local communities. The main types of spatial dynamics of contour algal communities in the considered localities are species sorting and mass-effect, less significant role is played by the patch dynamics.