Arthropod Communities in the Mountain–Arctic Ecosystems of the Kola Peninsula

The increase in air temperature and precipitation in recent decades has led to a rise in forest boundary in polar mountains, a reduction in low-temperature habitats, a decrease in the diversity of cold-adapted biota, and its displacement by thermophilic species. We investigated the current arthropod diversity and environmental conditions on peaks of the Khibiny mountain massif, which is the largest and most complex orography in the Kola Subarctic. The research was conducted at altitudes 1050–1090 meters above sea level, in the cold goltzy desert belt (GD), which is considered an analogue to polar deserts in the northern hemisphere. We used the standard 500 ml soil traps with formalin but applied a long-term trapping method for the first time in zoological studies on Khibiny peaks. The period of capture of arthropods was 60 days from July to September in 2023 (25 traps in five repetitions under the main types of vegetation and in bare rocky ground) and 90 days in 2024. As a result, 100 forest, polyzonal and boreal–montane arthropod species widespread in Holarctic and Palearctic were identified. Arctic, arctic–alpine and arctic–boreomontane species were rare, as is the case in the zonal and mountain tundras of Fennoscandia as a whole. Such boreal physiognomy of arthropod fauna on the peaks of the Khibiny Mts contrasts with local fauna on arctic coasts and sea islands, in which the proportion of arctic species reaches 40%. It is also contrasted with the flora of vascular plants, 65% of which is represented on the peaks of the Khibiny Mts by arctic species. These data help to understand the historical ways in which the Khibiny Mts were colonized after glacier retreat. The studies also revealed that such specific factors attracted forest arthropod species on Khibiny bare peaks, given the high atmospheric humidity, low soil acidity due to the physical weathering of alkaline rocks, and the good warming of substrates during the round-the-clock polar day.