The vegetation of Ob valley mires in the southern forest zone of Western Siberia
Lapshina, Elena D.
The aim of the present investigation was to describe the mires of the river Ob valley in the south of Western Siberia focussed on their symmorphology and a phytosociological classification in order to compare them with corresponding plant communities in Europe. The area investigated covers about 250 km2. Relevés were made in transects from the Ob terraces to the river on sample plots covering between 4 and 25 m2 in small sedge laws and up to 100 m2 on forested sites. Furthermore, the spatial structure was investigated and the site ecology was characterized by indication values using the Ramenski approach.The most productive sedge communities were indicated by the Caricetum lasiocarpae. A Triglochin maritimum variant is largely comparable with the communities in Central Europe, whereas the Calamagrostis neglecta variant shows the highest floristic affinity with that occurring in northeastern Poland. A typical feature for the Ob alluvial mires is the Betula humilis shrubland. It is differentiated as a weakly characterized community and syntaxonomically it is included within the Caricion lasiocarpae. Less productive sedge-Amblystegiaceae-communities were classified as Caricetum diandrae, which in the valley mires preferentially is developed in a Carex limosa-facies. Comparable syntaxa from northeastern Poland have been classified as Caricetum limosodiandrae. The Cariceta lasiocarpae and diandrae in Western Siberia are differentiated from the European ones by species such as Rumex aquaticus, Cicuta virosa, Brachythecium mildeanum, Drepanocladus aduncus, Agrostis gigantea and Trisetum sibiricum.Tallsedge-willow communities were classified as Carici juncellae - Salicetum rosmarinifoliae spiraeetosum salicifoliae and, together with the Salix rosmarinifolia-Menyanthes trifoliata-community, included in the alliance Salicion cinereae. The regionally quite common birch-pine-carr communities were described as Carici appropinquatae - Pinetum sylvestris ass. nov., floristically characterized by the hummock forming sedges Carex appropinquata and C. cespitosa and regionally differentiated by Calliergonella cuspidata.Alder swamps that occur in Central European mire borders, in southern West Siberia were replaced by so called "Sogna"-communities in Western Siberia. They are characterized by a tall tree layer of Pinus sibirica and Picea obovata. The most productive sites, characterised by Duscheckia fruticosa, were classified as Duscheckio - Pinetum sibiricae ass. nov.