Latitudinal gradient of diversity of macromycetes and vascular plants in the European part of Russia

Principles for the distribution of vascular plant diversity for large areas have been studied for a long time, but very little is known about distribution patterns of macromycetes, which are closely related in their existence to flora. The limited number of works on the biogeography of macromycetes are mainly based on the number of species of randomly selected territories of arbitrary size, which makes it impossible for us to compare these data with the results of studies in local flora obtained using a standardized method for collecting material. We conducted field studies of a model group of macromycetes — clavarioid fungi — in 143 localities, covering all vegetation subzones of Eastern Europe. The hypothesis that the richest mycobiota correspond to the most floristically rich regions was tested. We found that the richest local flora corresponds to forest-steppe regions, and in the direction of the tundra and steppes the number of species decreases sharply. A similar trend was also revealed for the macromycetes localities, but the peak of their richness corresponds to the south and hemiboreal regions. For both groups, the richest territories correspond to the mountainous areas framing the East European Plain. A strong positive correlation was found between the annual primary production, the stock of aboveground phytomass and mortmass, and the richness of vegetation and mycobiota. A positive relationship was also found between the richness of both biota components with the average annual rainfall, while a relationship with the hydrothermal coefficient was established only for local flora. A connection was found between the indicators of “energy” and vegetation cover, while this was absent with the mycobiota. The spatial trends of the taxonomic wealth of vascular plants and fungi are examined from the perspective of the systematic organization of biota. For mycobiota, there is a strong dependence on the “water” indicators, while, like for vegetation cover, taxa of different hierarchical levels behave each as a single separate whole. An attempt is made to discuss the applicability of the “mid-domain effect” to the revealed principles of the spatial distribution of the species richness of fungi.This research was supported by the Russian Foundation for Basic Research (project no. 18-05-00398) and carried out within the state assignment of Institute of Geography of the Russian Academy of Sciences (no. 0148-2019-0007)