The study deals with certain variations of the diversity level of clavarioid funga in the 33 localities (100 km2 each) inside seven longitudinal sectors (100,000 km2) situated along the gradient of the climatic continentality of the Eurasian tundra zone. As continentality increases, from the maritime climate of Fennoscandia to the continental climate of Yakutia, α-diversity and γ-diversity decrease considerably. On the other side, spatial turnover of species, or β-diversity, grows in the direction of continental areas. This paper uses the following methods to assess the spatial turnover: Whittaker's index and mean Jaccard similarity index, as well as by several other parameters. In addition, our data show that the genus Typhula is richest in the tundra, and its share in the structure of the clavarioid funga grows as the studied area decreases, as well as when the environmental conditions become more severe (continentality of the climate). Also, the paper discusses the issue of newly emerging taiga fungi species in the European Arctic, which is connected with climatic warming followed by ″greening″ of the tundra. Note that in the cryo-semiarid continental climate of Yakutia, where climatic changes are just as pronounced, no new taxons have been discovered so far.
Keywords: Arctic; biogeography; climate change; distribution; permafrost; spatial turnover.