Primary Succession of Soil Mites (Acari) in a Norwegian Glacier Foreland, with Emphasis on Oribatid Species

The distribution of soil mites was studied ill the foreland of the Hardangerjokulen glacier in central south Norway, Close to a glacier snout, which has been receding since 1750. Twenty sampling plots were distributed along a gradient spanning from 30 to 230 years, and five additional plots were in 10,000-year-old soil nearby. To, 2 standardize the microhabitat, all 320 soil cores (each 10 cm(2) and 3 cm deep) were taken in Salix herbacea vegetation. The main focus Was Oil oribatids. and most juveniles were identified to species. Two small, parthenogenetic species were pioneers, with high abundance ill young, soil: Tectocepheus velatus and Liochthonius cf. sellnicki, although their dominance values decreased sharply with time. The youngest soils also contained unidentified Actinedida and Gamasidae, and pitfall traps revealed the rather large, predatory actinedid species Podothrombium strandi. The number of oribatid species increased gradually with Soil age. The oldest soil contained 19 oribatid species. but Only six of them. all in low densities. were unique to this soil. Parthenogenetic species were present in all age classes of soil. Although there exist few earlier studies oil mite Succession ill glacial foreland soil, mites are clearly among the earliest colonizers along receding glaciers.