THE EFFECTS OF EXPERIMENTAL TEMPERATURE ELEVATION ON POPULATIONS OF CRYPTOSTIGMATIC MITES IN HIGH ARCTIC SOILS

Soil warming experiments were conducted in tundra heath and polar semi -desert soils at the High Arctic location of Ny-Alesund, West Spitsber gen, Svalbard. The warming treatment resulted in an 8-10% increase in the annual thermal budget for soil-dwelling oribatid mites (Crytptosti gmata). Samples of the oribatid mite populations were taken during thr ee summers using high gradient extractors, from warmed and control plo ts. Changes in population density were analysed for six species of ori batid mite. The oribatid mite fauna of these soils is well adapted to a wide temperature range and responds to short-term changes in the soi l microclimate. There was little evidence from this three-year experim ent that persistent above normal temperatures affected population grow th rates.