Inventory of sublittoral vegetation associations in the Far Eastern Seas of Russia

Sublittoral vegetation communities in the Russian Far Eastern Seas are still poorly and unsystematically studied. Scopes of the communities described by different authors are different or unclearly defined. Any general methodological framework that would allow systematizing their composition has not yet been proposed. The concept of adaptive zone (AZ) can be such methodological basis for systematizing diverse descriptions. AZ is understood as a vegetation cover area in which the living conditions of a single species are so favorable that it dominates in abundance over others and forms communities with its own dominance. Mosaic of these communities can be described as a vegetation association. Distribution of sublittoral vegetation communities in the Far Easters Seas is inventoried and analyzed using this approach on the base of information on dominant species of sublittoral vegetation in all available scientific literature where both quantitative data and verbal notes on species domination in certain areas are selected. In total, 67 associations are identified in 13 areas of the Far Eastern Seas. One third of the associations are narrowly distributed in a single region, a half of them are moderately distributed in 3–5 regions, the others are widespread in 7–9 regions. High-boreal areas are cenotically poor (5–11 associations in each), low-boreal areas are cenotically rich (23–31 associations in each). Within the regions, the vegetation composition is distinguished by high similarity in the Japan Sea (at least 62 %) and the northern Okhotsk Sea (at least 73 %). Signifi-cant thermo-cenotic (α = 1.7 ± 0.3, R 2 = 0.71, p = 0.0006) and flora-cenotic (α = 0.14 ± 0.06, R 2 = 0.56, p = 0.05) gradients are noted as the indices of natural increasing of the associations quantity from north to south that corresponds to the Humboldt-Wallace rule and represents its phytocenotic aspect. The ratio in the number of communities belonging to different systematic groups can characterize thermotropism of vegetation in vast or local areas.