Nature Conservation Research: Заповедная наука (Nov 2018)
Presentability of the Utrish Nature Reserve's benthic communities for the North Caucasian Black Sea Coast
Abstract
An assessment of the presentability of the biotopes and benthic communities of the northwestern part of the Utrish Nature Reserve marine area for the Caucasian Black Sea coast has been conducted. The literary and original data on the state of benthos in the area from the Kerch Strait to Adler were examined. The studied area of the Utrish Natural Reserve included habitats that are common along the coast (an active cliff, a narrow pebble beach, boulder deposits, rock bench and soft sediments). Only two of the three well-known Black Sea belt macrozoobenthic biocoenoses were observed along the northeastern Black Sea coast: the shallow-water «venus sand» and the deep-water «phaseolina silt». The third biocoenosis («mussel mud») was not noted neither in the reserve's area nor in the studied part of the shelf to the south of Novorossiysk. Of these three belts only «venus sand» was found in the Utrish Nature Reserve's marine area. The absence of the mussel belt in the studied area of the reserve is typical for the southern part of the North Caucasian coast in the current period and thus does not affect the presentability of the reserve's benthic ecosystem. The biocoenosis of the bivalves Pitar rudis – Gouldia minima was common at the muddy sand with shells in both reserve's and reference sites' middle-depths complex instead of the mussel belt which was typical for the 20th century. Its boundary was 10 m deeper in the reserve compared to the reference sites. The absence of the Modiolula phaseolina belt in the area of the reserve could be explained by the insufficient width of the protected marine area (up to 52 m depth); due to this the deep-water complex in the reserve is actually represented by a narrow strip. Extension of the reserve's boundary over the depth of 70 m will include this biocoenosis into the Protected Area, which would significantly increase the presentability of the reserve's marine part for the North Caucasian coast. The biogeographical composition of the reserve's flora, its species diversity and structure in general corresponds to that of the whole region. The macrophyte zone consists of four belts: upper (0–2 m, Dictyota fasciola f. repens + Polysiphonia opaca + Ceramium ciliatum + Ulva compressa), upper mid (2–12 m, Cystoseira crinita + Cystoseira barbata – Cladostephus spongiosus – Ellisolandia elongata), lower mid (12–18 m, Phyllophora crispa, Codium vermilara and Bonnemaisonia hamifera), and the lower belt (below 18 m) formed by a recent invader, B. hamifera. The majority of species found in the reserve's marine area are common species of the Black Sea macrophytobenthos. However, the Utrish Nature Reserve includes more favourable habitats for macrophytes than most of the North Caucasian coast, because the typical macrophyte Cystoseira spp. have been noted at greater depths in the reserve, in comparison to the remaining shelf.
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