Spatial Distribution of Oribatid Mites in Small Areas II. : The Distribution Pattern of Some Oribatid Species

Abstract

The spatial distribution of 11 oribatid species obtained from forest and grassland was analyzed using IWAO's ρ-index. Ten species were distributed contagiously. Colonies were loosely distributed in forest plots, but many were compact and small in grassland plots. Two species, Oppia nova and Tectocepheus velatus were found in all eight plots examined, and their degree of aggregation was higher in forest than in grassland plots. In the Picea-moss forest, degree of aggregation was lower in early winter than in spring, despite an increase in population density in early winter.