Influence of Ericaceae Shrubs on the Microbiological and Chemical Properties of Soils of the Alpine Heath of the Caucasus and Mountain Tundra Grassland of the Khibiny Mountains

Climate warming leads to a wider distribution of heather shrubs, with very biochemically active ericoid mycorrhiza, in mountain meadows of temperate latitudes, where less active arbuscular mycorrhiza predominates. Our working hypothesis was that the expansion of ericaceae could specifically change the taxonomic composition of the prokaryotic complex; increase the microbiological activity of soils (basal respiration, respiratory metabolic quotient, activity of hydrolytic enzymes, and nitrification and ammonification rates); and change the nitrogen, carbon, and phosphorus status of soils. These indicators were compared in different relief elements in the humus-accumulative horizons of Umbric Leptosol under shrubs and grasses in regions contrasting in climate and soil-forming rocks: the alpine wastelands of the Northwestern Caucasus and the mountain tundra meadows of the Khibiny Mountains. The same heather species grow in these regions, which makes it possible to isolate the direct specific influence of plants, regardless of other environmental factors. The specific effect of the presence of heathers has not been established. The soil properties were primarily influenced by the location of sampling (position in the relief, soil-forming rock). The second is the region of study (climate). The features of the prokaryotic complex specific to each sampling site are not interrelated with the studied chemical parameters and microbiological activity. Nevertheless, general differences in the prokaryotic complex are associated with pH_Н2O and indicators of the carbon (C_SOM), phosphorus (P_ext.min, C/P_SOM), and nitrogen (N_micr, C_SOM/N_ext, N-\({\text{NH}}_{4}^{ + }\)) state of soils.