The qualitative and quantitative characteristics of micromycete communities in soils along a toposequence from a floodplain to the summit of a carbonate plateau in the mountain landscape of the Polar Urals were investigated. The biomass of fungi in the studied soils varies within the limits of 0.13±0.01 – 1.63±0.81 mg/g. The main contribution to its structure is made by fungal spores (up to 100% of the total biomass). The length of mycelium of microscopic fungi in upper organogenic horizons of soils varies from 18.45±8.70 to 162.71±134.89 m/g. The total taxonomic list of cultured micromycetes includes 38 fungal species from 19 genera, two divisions and sterile mycelium. The smallest number of species (12) was recorded in the soil under the herb-grass-sedge-moss community in the lower part of the slope, and the largest number of species (18 species each) was recorded in the soils of the floodplain herb-grass-grass meadow and spotted dryad tundra. The Mucoromycota Division is represented by 10 species from the genera Linnemannia, Mortierella, Mucor and Umbelopsis. Fungi of the Ascomycota division predominate in mycocenoses of the studied soils on carbonate rocks. The genus Trichoderma (8 species) is the leader by the number of species. The genus Penicillium has low species diversity in conditions of weakly acidic and weakly alkaline reaction of the environment. It has been shown that the fungal complexes of soils developed on carbonate rocks are characterized by low abundance, poor species and genus diversity, and the dominance of sterile mycelium. In tundra conditions, the quantitative characteristics of mycocenoses in carbonate-containing soils depend on the composition and structure of the plant community as well as the organic matter content in the soils. The CaCO3 content does not determine the total abundance and biomass of fungi in soils, but it may influence the taxonomic structure of micromycetes through an increase in pH.
M.A. Korolev (Wed,) studied this question.