Syntaxonomy of annual and summer supralittoral and pseudolittoral macroalgal communities of the North Caucasian coast, Black Sea

Annual and seasonal (summer) supra- and pseudolittoral macroalgal communities of the northeastern Black Sea coast have been described for the first time, using the floristic classification method. A total of three associations, one community, one alliance, one order, and one class have been identified. The associations, community, alliance, and order have been described for the first time. Diagnostic species are provided for the identified syntaxa. Based on the dominant classification method, the identified phytocoenoses are compared with those previously described from the Black Sea and with similar communities from the Mediterranean Sea and other European seas. It is shown that the annual and summer vegetation on hard substrates in the supra- and pseudolittoral zones of the northeastern Black Sea mainly consists of simple species-poor communities, which are predominantly comprised of cosmopolitan and subcosmopolitan species, along with a few species of the Indo-Atlantic, Atlantic-Pacific, and Mediterranean origin. However, the communities’ diversity is significantly poorer in the northeastern Black Sea supra- and pseudolittoral than that in the Mediterranean Sea, mainly due to lack of communities of calcifying red algae. An indirect ordination analysis revealed the ecological isolation of the described phytocenoses and the main factors influencing the floristic composition of communities: depth, eutrophication, and/or hydrodynamic intensity.

syntaxonomy, macroalgae, Black Sea, shallow waters, warm-water communities