Geographical variability of biotopic preferences of Sphagnum wulfianum Girg. in the Northern Palearctic

Sphagnum wulfianum is a widespread circum-boreal species in the Northern Hemisphere. We studied its distribution in the Northern Palearctic by generalizing and combining data from open sources (GBIF, literature data) and herbarium samples from LE, MW, NSK, and MHA into a single database. The database created in this way included 3061 samples. Data from herbarium labels and annotated lists of regional bryofloras are placed on the map of the Northern Palearctic as points in the ArcGIS software. The biotopic distribution and its variability across regions and natural zones are studied. The analysis of geographical distribution shows that out of the total number of samples, 99.3% (3041 samples) were found in the forest zone of the Palearctic, 0.5% (15 samples) - in the tundra zone and 0.2% (5 samples) - in the forest-steppe zone. This suggests that tundra and forest-steppe are atypical biomes for S. wulfianum . Typical biotopes that this species prefers are polytrichum-type of pine and spruce forests, where 49.8% of all samples are recorded, and bogs (17.9%). In bogs, Sphagnum wulfianum is found mainly in the peripheral parts of the range, especially in the tundra and forest-steppe. In the European part of the Northern Palearctic, its distribution almost completely coincides with the boundaries of the areas of Picea abies and P. obovata . Beyond the Urals - in the Asian part, such conjugation is observed only along the southern border of the distribution of spruce trees. Up to the northern border of spruce Sphagnum wulfianum doubles in Western Siberia, in Eastern Siberia its records are found much further south.