DISTRIBUTION, COMMUNITY STRUCTURE, AND MICROHABITATS OF SOIL INVERTEBRATES ALONG AN ELEVATIONAL GRADIENT IN TAYLOR VALLEY, ANTARCTITA

Soils in the Antarctic Dry Valleys have been significantly influenced by soil formation factors such as parent material, climate, and topogr aphy. Factors common in more temperate zones, including chemical weath ering and leaching of minerals, occur to a much lesser extent in these cold arid soils, leading to an accumulation of salts and bases, which will likely affect the distribution of soil biota. Since the intensit y of these factors may vary with topography, this study examined the s oil properties and soil invertebrate communities along an elevational gradient in Taylor Valley, Antarctica. We sampled from two spatial sca les (1 X 1 m and 10 X 10 m) at three sites (83, 121, and 188 m a.s.l) on the south side of Lake Hoare in Taylor Valley, and examined soil mo isture, nitrogen, carbon, pH, and electrical conductivity (which provi des an estimation of soil salinity), as well as the distribution and c ommunity structure of soil invertebrates. We found significant differe nces in soil properties with elevation, along with associated differen ces in soil communities. Biodiversity was greatest at the lowest eleva tion, closest to the shore of Lake Hoare, where soil moisture, carbon, and nitrogen were highest, and salinity was lowest. Scottnema lindsay ae dominated the nematode communities found at all sites. Electrical c onductivity was higher and carbon and nitrogen contents were lower at the upper elevations. The distribution of both Eudorylaimus and Plectu s appeared to be influenced by soil moisture; electrical conductivity affected the mortality of all three nematode genera found. Soil proper ties did differ with sampling scale, suggesting that changes in microh abitats not detected at sampling intervals of a meter or more may be m ore reliably detected by sampling at a smaller scale.