Communities of Moss Mites (Oribatei) in a Gradient Area

Data are presented showing patterns of frequency and abundance of soil inhabiting Oribatids associated with a gradient area. This area extends as a strip from the margin of a cultivated field to the edge of a (formerly) ombrogenous Sphagnum bog. Some 113 species of Oribatids belonging to 15 superfamilies have been taken in the monthly samples on different parts of the ninepoint collection line. The mean number of individuals per sample unit shows annual fluctuations and varies with respect to sample site and time. The vertical dispersion of adult Oribatids differs along the gradient as well as seasonally. Some congeneric species studied show a preference for different sections of the strip, which may be caused by intrageneric competition and special autecological requirements. It is possible to group sociologically four isovalent communities of Oribatids with indicator species. The gradient area represents a sequence of associations and of influencing operative factors.