Lake Kryazh plant communities (Ulyanovsk region): 2. Syntaxonomic structure

The plant communities of Lake Kryazh and the plant species that form them are found in the southern part of Ulyanovsk Region. Therefore, they are very rare and have a somewhat different ecological affinity compared to their populations in the range center. So, the data on the syntaxonomic vegetation structure from the standpoint of ecological and floral classification are of great scientific interest. Materials and Methods. The article is based on the description of trial plots (a total of 65 descriptions). Field geobotanical studies (area descriptions and geobotanical mapping) were carried out according to generally established methods. Braun-Blanquet’s way of classifying a plant community was used. Results. It is found out that the vegetation Lake Kryazh floating bog and adjoining wetlands is represented by 7 associations, 8 subassociations and one unit, which cannot be classified: association Sphagno angustifolii-Caricetum limosae Blagov, 2014; association Sphagno fallacis-Caricetum lasiocarpae Steffen, 1931 (subassociation menyanthetosum trifoliatae Smagin, 2012); Sphagno fallacis-Caricetum rostratae Steffen, 1931 (subassociation menyanthetosum trifoliatae Smagin, 2012); Comaro palustris-Caricetum rostratae Smagin, 2012 (subassociation typicum and sphagnetosum angustifolii Blagov, 2014); Comaro palustris-Caricetum lasiocarpae (Tuxen 1937) Smagin, 2012 (subassociation typicum and sphagnetosum angustifolii Blagov, 2014); Carici lasiocarpae-Betulo pubescentis-Sphagnetum (Kaks 1914) Blagov, 2006 (sphagnetosum fimbriati Blagov, 2006 and 1991 sphagnetosum angustifolii Smagin, 1991); Frangulo-Salicetum cinereae Malcuit, 1929; non-classified unit Phragmites + Thelypteris palustris-Sphagnum flexuosum + S. fimbriatum. Potametalia Koch 1926 and Lemno-Utricularietalia Passarge 1978 are widespread in the lake water column and on the surface. Conclusion. The syntaxonomic structure of the Lake Kryazh is diverse and unique. Some of the syntaxons are located within the southern distribution limit and the communities, to which they belong, can be considered as reference ones for the forest-steppe of European Russia and are subject to protection.