Spatial diversity of clavarioid mycota (Basidiomycota) at the forest-tundra ecotone

The article studies the change of clavarioid mycota species richness along the longitudinal gradient of climatic continentality in the forest tundra ecotone of Eurasia and the results are discussed for continental and regional levels using the basic climatic variables. It was found that species richness declines, both continentally and regionally, with climate continentality increasing. The Fennoscandian sector situated in the mild maritime climate is the richest, whereas Yakutia, with an ultracontinental harsh climate is the poorest. Strong positive correlations were found between species richness and mean annual temperature and precipitation. On the other hand, spatial turnover of species, or beta diversity, has a negative correlation with the macroclimatic gradient. There are European sectors, where clavarioid mycota associating with the birch and pine-spruce open woodlands have high similarity with their boreal variants, whereas in Siberian sectors, east of the Yenisei River, where mycota is associated with larch and cedar elfin bushes, the similarities are more akin to tundra variants. At the continental scale, there is no reliable relationship between mycota diversity with the flora richness and soil pH, but the permafrost thickness is significantly correlated with the studied levels of the clavarioid mycota diversity.