Ecological groups of vascular plants in the estuaries of the White Sea rivers
The article presents the results of studies on the main ecological groups of vascular plants of the White Sea coast: obligate, facultative halophytes and species tolerant to salinity. The ratio of species included in these groups of coastal plants varies slightly in different regions of the White Sea. The central core of the coastal flora of the sea is made up of obligate and facultative halophytes, for which the growing conditions on saline sea coasts are optimal. Studies carried out in different estuaries of the White Sea rivers for the vegetation of drylands covered daily by the tide showed that obligate halophytes tend to grow in zone I - which is characterized by constant salinization, where water salinity does not drop below 1 % during low water periods. The occurrence of obligate halophytes decreases in zone II with periodic salinization, where growth conditions are optimal for facultative halophytes. Tolerant types growing on silty drylands are more common in zone III, characterized by episodic salinization, where saline waters penetrate only during syzygy tides and surges.