Abstract. Kostryukova A, Mashkova I, Belov S, Shchelkanova E, Trofimenko V. 2021. Short Communication: Assessing phytoplankton species structure in trophically different water bodies of South Ural, Russia. Biodiversitas 22: 3530-3538. The study aims to analyze the species structure of the phytoplankton communities of four water bodies in South Ural (Lakes-Turgoyak, Uvildy, Ilmenskoe and Shershnevskoe reservoir). These water bodies are characterized by different trophic states and levels of anthropogenic impact. Lake Turgoyak is oligotrophic; Lake Uvildy is oligomesotrophic. Both water bodies are protected areas and natural monuments. But tourism and recreation are not prohibited on their territories. The mesoeutrophic Lake Ilmenskoe is partially located within the Ilmen State Reserve, and it experiences less anthropogenic impact. The eutrophic Shershnevskoe reservoir is located within the boundaries of the city of Chelyabinsk. It is used as a source of drinking water. Cyanobacteria was the dominant division in the eutrophic Shershnevskoe reservoir. Bacillariophyta dominated in the plankton communities in oligotrophic Lake Turgoyak and oligomesotrophic Lake Uvildy. Green and blue-green algae biodiversity increased in the oligomesotrophic Lake Uvildy. For the mesoeutrophic Lake Ilmenskoe, diatom algae are dominant, but a higher proportion of Chlorophyta (especially Cyanobacteria) was revealed. Species similarity among phytoplankton communities in the given lakes was studied through cluster analysis based on the Sorensen-Czekanowski coefficient. The higher level of similarity between plankton species compositions could be explained by their locality rather than their trophic status.

ABSTRACT:The present study aimed to assess the long-term dynamics of the synanthropic vegetation of the road and path network of the Ilmen State Reserve. The analysis of the synanthropic species spread among coenofloras of the elements of the road and path network revealed an increasing synanthropization index in the gradient of the stress factor for all forest types. Pine forest is the most resistant to the introduction of synanthropic species. The paper considers the element composition in the period before seed formation. 10 weeds most common in the central regions of Russia were analyzed. The studied weeds can accumulate metals in their green mass. Some wild plants are potentially resistant to metals, as they can grow on heavily dirty substrates. The analysis of the vegetational metals shows that most of the species do not translocate metals into their overground part, so they act as excluders. Due to the human-made impact on the natural landscape, synanthropic species of plants are taking a significant place in the structure of biodiversity.

The current paper considers changes of phytoplankton community structure in three South Ural (Russia) water bodies different in trophicity: Lake Uvildy, Lake Ilmenskoe, and Shershnevskoe Reservoir. There is no clear relation between the changes of species structure of phytoplankton communities and water-bodies trophicity. The least significant changes in the phytoplankton community structure are registered for the mesoeutrophic Lake Ilmenskoe, which is located on the territory of the State Reserve. Diatomic, green and blue-green algae groups are the most diverse in composition in the studied periods of 1936-1937, 1964-1984 and 1998-2016. But for the last 20 years, Cyanophyta has increased its contribution into the phytoplankton number and biomass of Lake Ilmenskoe. The representatives of the Bacillariophyta group dominate in oligotrophic Lake Uvildy. In 1965-1985, the Chlorophyta group was the most abundant in Shershnevskoe reservoir (34 % of the total number of species), Bacillariophyta -32 % and Cyanophyta – 18 %. In 2003-2005 and 2017 the number of green algae increased (Chlorophyta – 40 %) and that of diatoms decreased (Bacillariophyta -21%) with the number of blue-green algae being unchanged (Cyanophyta -19 %). The ecological status of the Shershenevskoe Reservoir has transformed from a long-term sustainable mesotrophic to eutrophic. So, for oligotrophic lake Uvildy and mesoeutrophic lake Ilmenskoe, Bacillariophyta group is characterized by the greatest taxonomic diversity. While for eutrophic Shershnevskoe Reservoir the absolute abundance of Chlorophyta algae group is marked, which is growing in time. The growing importance of blue-green algae is one more feature of the change of a trophic status.