Northern distribution limits of Sphagnum wulfianum (Sphagnaceae, Bryophyta) in the Northern Palearctic – records from tundra: coincidence or rule?

Abstract

Sphagnum wulfianum is a widespread circumboreal species in the Northern Hemisphere. The distribution of this species in the Northern Palearctic was studied by generalizing and combining data from open sources (GBIF, literature data) and herbarium samples from LE, MW, NSK, and MHA into a single database. Data from herbarium labels and annotated lists were put on the map of Eurasia as points in the ArcGis 10.0 software. Analysis of the data shows that out of 3061 points 15 samples only were found in the tundra zone, which is 0.49% of all samples. This demonstrates that tundra habitats are not typical for S. wulfianum. Spatial analysis of samples collected in the Arctic of Eurasia shows that S. wulfianum was found only in the tundra of Yamal, Taz, and Taimyr peninsulas and in the part of Bolshezemelskaya tundra, which is adjacent to the Polar Urals. Analysis of vegetation history shows that S. wulfianum is a relic of the Holocene climatic optimum, preserved in the present southern tundra since the existence of forest vegetation. It is unknown from the tundras of Yakutia and Chukotka and from the mountainous tundras of Scandinavia, where any forest vegetation is unknown in the Holocene.