Studying spatial distribution of planktonic, benthic and periphytic algal metacommunities in aquatic ecosystems of different types

Applying the metacommunity theory to studying biodiversity of continental aquatic ecosystems is an important issue in modern hydrobiology. Metacommunity is a set of local communities connected with each other by dispersal of potentially interacting species. Of special interest are complex studies of spatial dynamics of planktonic, benthic, and periphytic algae, which are distinguished by high taxonomic diversity and form the primary link of energy fluxes in aquatic ecosystems. The aim of this paper was to develop and put into practice some components in studying spatial distribution of algal metacommunities in the horizontal plane, along the vertical axis and in the three-dimensional space in continental aquatic ecosystems of different types. Horizontal distribution of algal metacommunities can be analyzed with the help of the geographic approach based on the «Distance Decay of Similarity» concept. On the grounds of the «Distance Decay of Similarity» approach a combined approach has been developed, which combines two independent parameters (geographic distance and spatial isolation of localities) into one parameter – «spatial factor», which we propose to assess in points. This combined approach has been shown to give more statistically significant data, than the classical geographic approach. It is necessary to study vertical dynamics of algal metacommunities both with changing the locality type in the systems «plankton « benthos», «plankton « epiphytic communities», «benthos « metaphyton « (plankton)», and within homogeneous locality – vegetation of algae in different layers of the pelagic zone: surface layer – middle layer – near bottom layer. The dominant species of phytoplankton, causing algal blooms in the Dnieper water reservoirs, can precipitate from the water column upon the bottom and higher aquatic plants and in this way increase the species richness and abundance of benthic and periphytic algal communities. The proposed integrated approach to using the three-dimensional space is necessary in studying the interaction among phytoplankton, benthic and periphytic algal communities forming the holistic top-to-bottom autotrophic link in lotic and lentic ecosystems.