Complex Ecological Study of the Fjell Field in the Khibiny Mountains

Ecosystems of the fjell fields in the Khibiny Mountains (Kola Peninsula) are investigated, including vegetation, soils, soil algae, and invertebrate fauna. We use EUNIS habitat typification (2013) to differentiate habitats. The most common habitat types include (1) crustose–lichen (Rhizocarpon geographicum) rock on eluvium of base-rich, alkaline, and siliceous rocks (U5111); (2) lichen-, sedge-, and dwarf- and shrub–dominated turfs and cushions on gravelly and rocky slopes (U5112); (3) sedge-, moss-, and lichen–dominated on rubble and stony mountain plateaus and peaks (U5113); (4) biological soil crust on fine-earth and gravelly polygon edges (U5114); and (5) late snow bed moss vegetation (U5115). Soils of the fjell fields are represented by Leptosols. The content of soil organic C is very high (26–32%), despite the thin soil profile, which has no illuvial–eluvial differentiation by the content of SiO₂ and R₂O₃. The total flora includes 176 species of plants and lichens. Soil alga flora is composed of 43 species, where green algae of Chlorophyceae prevails. Soil microarthropods are dominated by Collembola, Oribatida, and Mesostigmata, which are also typical for mountain tundra. The soil microbial activity and the diversity and abundance of soil algae and invertebrates depends on the habitat type and soil moisture, as well as on soil organic matter content and increases on wet substrates or under more complex vegetation.