Spatial Distribution of Oribatid Mites in Small Areas : I. Survey Areas and Oribatid Faunas

Abstract

An account if given of the interspecific correlation and the similarity among oribatid species compositions of eight different plots. Oribatid mites were collected from the soil layer of eight plots set in two Picea-forests and one moorland in Hokkaido, and two grasslands in Tochigi Prefecture. Soil samples were taken serially of each plot (50×60 cm2 and 5 cm in depth) using a total of 150 samplers in May and November 1972. The total(individual) number of collected oribatid mites varied from 507 for the moorland in May 1972 to 8, 738 for the Picea-forest in November, 1972. Four species, Cultroribula lata, Malaconothrus pygmaeus, Oppia nova and Teactocepheus velatus, were common to all plots. The former species was abundant in the grassland and the latter two were adundant in the forest.Analysis of similarity among oribatid communities of eight plots using the Cλ index gave high values among five plots of the Picea-forest. A somewhat high value was obtained between communities of the two grasslands. The value of Rδ showed a highly positive interspecific correlation for the following combinations : T. velatus-Nanhermannia nana, T. velatus-O. nova, T. velatus-Steganacarus striculus, O. nova-N. nana, O. nova-Perlohmannia coiffaiti, O. nova-S. striculus, O. nova-Metrioppiidae sp., S. striculus-Metrioppiidae sp., S.striculus-N. nana, Rostrozetes foveolatus-M. pygmaeus, R. foveolatus-Scheloribates latipes and P.coiffaiti-N. nana.