LAUSR

ABSTRACT We studied how ecological factors affect species composition and structure of soil algal assemblages in different types of mountain tundra and sparse forests in the Northern Urals. Soil moisture, pH, nitrogen content and amount of solar radiation were determined using Ellenberg indicator values from phytoindicators. Species identification of soil algae was made using light microscopy following algal culture. We identified 74 algal species from five divisions. Most species were Cyanobacteria and Chlorophyta. For each habitat type we identified species with high frequency and fidelity. Algal species diversity was maximal in herbaceous plant communities, minimal in lichen communities, and showed a positive correlation with soil moisture and nitrogen content.