Communities of macroscopic red algae (Lemaneetea fluviatilis) in rivers of the Upper Volga region and adjacent territories

Communities of macroscopic red algae in rivers of the Upper Volga region and adjacent territories are considered. Their classification based on the Braun-Blanquet approach is proposed. Phytocoenoses belong to the class Lemaneetea fluviatilis and the order Lemaneetalia fluviatilis. Two alliances Lemaneion fluviatilis and Batrachospermion gelatinosi separate the plant communities of fast and slow flowing waters. The first mentioned alliance includes the association Lemaneetum fluviatilis only, the second one unites the associations Batrachospermetum gelatinosi, Batrachospermetum turfosi and the community Sirodotia suecica. Almost all syntaxa are published validly for the first time. The characteristics of syntaxonomical units are given. Data on species composition, structure, ecology and distribution of the revealed phytocoenoses are presented. The communities of red algae are the most diverse in the rivers of the western part of the Vologda region, where all studied syntaxa are recorded. The plant communities of the association Batrachospermeum gelatinosi are the most common in watercourses of the region. Investigated rhodophyte phytocoenoses are rather sensitive to any changes of environmental conditions indicating the purity of river waters. They can be recommended for conservation purposes.