TAXONOMIC DIVERSITY OF BENTHIC ALGOFLORA OFF THE WESTERN COAST OF THE CRIMEAN PENINSULA

Abstract

The article presents the results of the study of benthic flora along the western coast of the Crimean Peninsula (Sevastopol region, Black Sea) in the summer of 2020. Hydrobotanical studies covered the water areas of Cape Tyubek, Lukull, VaiVai, Margopulo, Nemetskaya and Yazykovaya Balka. The flora included macroalgae of 74 species from the departments Chlorophyta, Heterokontophyta and Rhodophyta. The identified taxonomic composition was characterized by high species saturation of suprageneric taxa and low genus coefficient (1.1–2.0), coincidence of the proportion “order/family” in the divisions and in the whole algoflora, as well as “order/family/genus” in Heterokontophyta and Rhodophyta. The basis of taxonomic diversity was the following Rhodophyta (Ceramiales, Corallinaceae, Rhodomelaceae, Ceramiaceae), Chlorophyta (Cladophorales, Ulvales, Cladophoraceae, Ulvaceae), Heterokontophyta (Ectocarpales, Chordariaceae). Multispecies orders and families united from 55 to 88% of the total number of species found. High species diversity was characteristic of the genera Cladophora, Ulva, Polysiphonia and Ceramium. Seventeen species included in the national Red Data Books and international lists were found in the studied areas of the western coastal zone, which indicates the conservation significance of the study area. The large proportion of permanent species, their high joint contribution with additional species, the presence of maximum occurrence in a quarter of species (100%), and the average value of Jaccard’s coefficient (60%) testified to the spatial homogeneity of the species composition in the studied water area, which corresponded to relatively uniform habitat conditions of hydrobionts along the open sea coasts. Spatial changes in taxonomic composition were moderate (Cv = 9–26%). The difference in the extreme values of the absolute number of taxa was insignificant (by 30-50%). Among the departments, Chlorophyta was characterized by the lowest variation in the number of taxa, and Rhodophyta – by the highest. The increase in the difference between the extreme values of the absolute number of taxa was realized in the direction of orders < families < genera < species. The results of phytoindication indicate the warm-water character of the flora and the emerging trend of increasing trophicity of algal habitat in the study area.