Composition and structure of benthic macroflora of protected water areas (Crimea, Black Sea)

Along the coast of Crimea there are 31 objects of the reserve fund, including natural monuments of hydrological profile. With the increase of anthropogenic impact on protected marine objects, their biodiversity is decreasing. There is a need to make forecasts of the impact on the coastal zone based on the results of long-term observations. The available information on the composition and structure of the benthic flora of protected sites in the Black Sea cannot be considered complete at present, especially as some of it was obtained in the last century. Hence the aim of the study was to investigate the species composition, taxonomic structure and peculiarities of species occurrence in the benthic macroflora of specially protected natural areas of Crimea. The research was conducted in the water area of natural monuments near the capes Lukull, Fiolent, Sarych, near the Chersonese Tauride, near the Diva Rock and Mount Koshka. Samples were collected in the summer of 2020–2021 using the methods of vertical transects and survey sites. The summer macroflora of the protected sites included 114 species of algae of 71 genera, 40 families, 26 orders, 6 classes of Chlorophyta, Heterokontophyta and Rhodophyta. The greatest species diversity among the divisions is characterized by Rhodophyta, among orders, families and genera – Ceramiales, Rhodomelaceae, Ulva and Cladophora. The most stable components of the taxonomic structure are quantitative ratios of species/family, species/order and family/order. Species saturation of genera in Chlorophyta is twice higher than in other divisions. All divisions are characterized by high species abundance of orders. More than 24% of species with conservation status of different categories inhabit protected sites. Most of them belong to the category of species whose abundance indicators are currently decreasing. The occurrence of species in the water area of all natural monuments varied widely, reaching on average 70%. The basis of the benthic flora was formed by species of the permanent group, the second position was occupied by occasional species with a low level of occurrence. Rhodophyta representatives dominate among the species that have occupied all protected water areas. The constant core of the flora includes Gongolaria barbata (Stackh.) Kuntze, Ericaria crinita (Duby) Molinari et Guiry and Phyllophora crispa (Huds.) P.S. Dixon. The values of Jaccard's species commonality coefficient and homotony indices indicated a high degree of qualitative homogeneity of the benthic flora in the study areas.