Spatial variability of fouling macroflora of hydraulic structures in various regions of the crimean Black Sea coast

Abstract

Introduction. The macroflora of Black Sea coastal hydraulic structures and its stability under the influence of external factors remains poorly studied. Some published papers present the results of comparative analyses of phytoperiphyton and phytobenthos in several bays of the Sevastopol Region. To enhance the insight into the role of algae in fouling of hydraulic structures in coastal ecosystems, hydrobotanical studies were conducted along the Crimean coast of the Black Sea. Methods. In the summer of 2017, samples were taken at 31 stations in five areas along the Crimean coast from the side wall of beach-retaining hydraulic structures (jetties) using the method of accounting areas. To assess the influence of external factors on the spatial distribution of taxonomic composition, the parametric method of two-way analysis of variance was used. Results. Fouling of coastal structures at 31 stations in five areas was found to contain 101 species of macroalgae, among which Rhodophyta is predominant. The Feldman’s index points out that the studied phytocoenon is close to subtropical flora. The distribution of species by constancy groups was uneven. The significant proportion of random and inactive species indicates significant qualitative diversity of algal fouling in different areas. The absolute number of periphyton species varies considerably both from station to station and between the areas. The average number of species of Chlorophyta, Rhodophyta and the entire community does not change as significantly between the areas as the average number of Ochrophyta species. The study also describes the ecological composition of fouling macroflora. Among the groups with a different frequency of occurrence in the Black Sea, leading species prevail with the maximum absolute number in the south and the maximum relative number in the west. Fouling algae are mainly annual, marine, and oligosaprobic, and their composition is the most diverse in the south-west and south. The species composition of the ecological groups was found to be spatially stable. The two-way analysis of variance showed that such factors as the geographical (spatial) location of a substrate and species attribution to particular divisions have a significant and independent influence on the distribution of the number of species.