LONG-TERM CHANGES IN WINTER TEMPERATURES IN THE UPPER KOLYMA R AREA AND THEIR BIOTA IMPACTS. Report 1. Temperature changes and wintering conditions of the ants
Since 1960ies till the present, the rise in the minimum air temperatures has been 3-4°C in the Upper Kolyma R. Area, that is twice as high as the average temperature changes during a cold season there. Fluctuations in snowfalls and snow cover differed by their time, significance and value throughout the study area. Combined effects of the air and snow cover temperatures resulted in widely changing minimum temperatures ranging from 5-6°C above 0° to 1-1.5°C below 0° in the upper 40 cm of soils in the area of consideration. A 2.5-3°C growth in the minimum soil and ground temperatures resulted in a noticeable increase both in the number of biotopes and frequency of Formica exsecta. that is the least cold-resisting ant species, which however has become a dominating one among invertebrates. Similar changes are assumed to have taken place in other species as well.