MACROZOBENTHOS IN THE EPIPHYTON OF ALGAE CYSTOSEIRA CRINITA DUBY, 1830 NEAR THE COAST OF CRIMEA AND THE CAUCASUS (BLACK SEA)

Abstract

The article provides summarized data of species composition, abundance, biomass, occurrence and trophic structure of invertebrate macrozoobenthos associated with red-book algae Сystoseira crinitа Duby, 1830 in the coastal waters of the Crimea (Cape Tarkhankut, Kruglaia Bay, Simeiz, «Cape Martyan» Reserve, Dvuyakornaya Bay) and the Caucasus (in the area of «Utrish Nature Reserve») in August-September 2012–2017 at the depth of 1, 3 and 5 m. A total of 46 samples were taken (42 quantitative and 4 qualitative). In the area of Utrish, such studies were carried out for the first time. In the algae communities of the Black Sea coast of Crimea and the Caucasus 56 species belonging to the types Annelida, Platyhelminthes, Mollusca and Arthropoda were identified. Ten species are common to all areas. The abundance and biomass near the Caucasus coast were 1432 ind. kg-1 and 9,52 g∙kg-1, near the coast of Crimea these values varied from 2506 to 6085 ind. kg-1 and from 23,9 to 43 g∙kg-1 respectively. Mollusks and crustaceans dominated in values of abundance, mollusks dominated in values of biomass. The highest quantitative indicators were recorded in the waters of Simeiz, the lowest – in the area of the «Utrish» Nature Reserve. Molluscs, in particular, Mytilaster lineatus Gmelin, 1791, make a significant contribution to the formation of macrozoobenthos abundance in the Simeiz area, while in the water area of Utrish the peaks of abundance have been defined due to crustaceans Ericthonius difformis M.-Edwards, 1830 and Ampithoe ramondi Audouin, 1826. Gastropods Rissoa splendida Eichwald, 1830, Bittium reticulatum (da Costa, 1778) and bivalve M. lineatus make the greatest contribution to the biomass of macrozoobenthos both in the waters of Simeiz and in the Utrish Reserve area. The high abundance and biomass of these molluscs allow them to form a macrozoobenthos nucleus in the studied water areas. Comparison of species composition of macrozoobenthos by the Chekanovsky-Sörensen community index showed high fauna similarity in all areas (the coefficient ranged from 0,4 to 0,76), as they are bound by the same biotope. The fauna of the Kruglaya Bay and Cape Tarkhankut are the most similar to each other. The areas in Dvuyakornaya Bay and Cape Martyan are the least similar to each other. The results of the cluster analysis confirm that the most similar areas in terms of presence/absence of species are Kruglaya Bay and Cape Tarkhankut, and also Dvuyakornaya Bay and Utrish area. The functional abundance index determined the communities of gastropod molluscs R. splendida (in the Tarkhankut, Simeiz and Utrish areas), B. reticulatum (in Kruglaya Bay) and bivalve M. lineatus (in Cape Martian and Dvuyakornaya Bay). It has been shown that the R. splendidа communities are more attracted to open coasts. In the R. splendida community from 16 to 25 species have been recorded in different areas, in the M. lineatus community in the water areas of the Cape Martian and Dvuyakornaya Bay (only quantitative samples were taken into calculation) 16 and 17 species were identified, in the B. reticulatum community – 25. In the majority of communities the guiding species were predominated. Their proportion was between from 32 to 56 % of the total number of species. Characteristic species dominate only near Utrish. Their share is 36 %. The number of rare species in communities varies from 3 to 9. The dominance-diversity curves indicate a more stable state of the epiphyton community in the water areas adjacent to the Utrish Reserve and Kruglaya Bay. Shannon index values also indicate high biodiversity in the studied water areas. The maximum Shannon Index value in terms of abundance was recorded in the B. reticulatum community (2,66) in Kruglaia Bay and a high value in terms of biomass (2,34) was marked in the R. splendida community in the Simeiz area. Five trophic groups have been identified. Phyto- and polyphages dominate by the number of species. Phyto- and sestonophages dominate in values of abundance, phytophages – in values of biomass.