The structure of bottom communities as an indicator of the small stream ecological state (based on examples of Primorye streams, Russian Far East)

Drozdov G.K., Tishchenko G.S., Vshivkova T.S.

В издании The 6th Biannual Conference of the Asian Society for Hydrobiology: Program & abstract book

Год: 2024 Страницы: 64

Problems of conservation of freshwater resources require a well-developed system of monitoring and control from both the state and public sides. This is especially true for small water bodies, which are the most defenseless in the face of growing urbanization. This problem can be solved with widespread public involvement in saving small rivers. In the Primorsky Territory, the movement to save small reservoirs and study their ecological state using bioindication methods is becoming increasingly popular. To this end, scientific institutes of the Far Eastern Branch of the Russian Academy of Sciences and the Scientific & Public Coordination Center “Clean Water Center” are developing methodological guidelines and manuals for public experts – simple, but adequately reflecting the ecological state of streams. Since 2020, we have been included in a group of schoolchildren and students to assess the ecological state of small rivers in Primorye based on macrozoobenthos under the auspices of the NGO “Clean Water Center”. Goal: To study the composition and structure of benthic communities of macrozoobenthos in 6 streams of the Primorsky Territory, located in riverbeds with varying degrees of anthropogenic impact, in order to identify trends in changes in communities during environmental disturbances. Objectives: 1. To identify the taxonomic composition of macrozoobenthos in selected watercourses. 2. Describe the species structure of benthic communities based on abundance indicators. 3. Analyze the main metrics of biodiversity and calculate biotic indices in 6 studied areas of selected watercourses. 4. Determine the water quality of the studied sites based on aquatic invertebrates, and identify patterns of changes in the bottom community structures under anthropogenic impact. The 6th Biannual Conference of the Asian Society for Hydrobiology 64 Results. 1. The taxonomic composition of macrozoobenthos has been revealed: the list includes 42 species from 23 genera, 22 families, 11 orders and 5 types of animals. 2. The species and trophic structure of macrozoobenthos communities is described and 3 types of communities formed under different levels of anthropogenic impact are identified; a) clean water communities (rivers located into or at the protected areas); b) communities of clean streams, but with mechanical disturbances of the channel and deforestation (small streams of the All-Russian Children’s Center “Ocean”, here hydrochemical indicators were normal, but the structure of the communities was sharply different from the natural one (in comparison with the situation before deforestation); c) communities of polluted waters in conditions of chronic pollution and deforestation cover (the Second Rechka River, located in the city center and has been in a zone of strong anthropogenic impact from many sources of pollution for more than 80 years). 3. Water quality was assessed using 9 biotic indices: Goodnight-Whitley, Woodiwiss, EPT, HT (High Taxa Index), FBI (Family Biotic Index), BMWP (FE Biological Monitoring Working Party Index), FE ASPT (Average Score Taxon Index), SO (Sensitive Organism Index), FE PSI (Far East Proportion of Sediment-Sensitive Invertebrates Index). 4. It has been shown that the deforestation and mechanical disturbance of the stream channel in the water protection zone causes fundamental changes in the structure of benthic communities: in our example, before deforestation, crustacean Gammarus koreanus Ueno, 1940 dominated (shredders), which is typical for undisturbed south far eastern forest streams; and after deforestation, dipterans Chironomidae (collector-gatherers) and Simuliidae (collector-filterers) became dominants.

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