Comparison among Oribatid Faunas from Different Microhabitats in Forest Floors

Abstract

For the purpose of sampling oribatid mites, floors of six natural forests in Hokkaido were stratified. These natural forests included Gm (Picea glehni-moss), Gr (P. glehni-Ph. communis), Gs (P.glehni-Sasa amphitricha), Fs (Fagus crenata-S.paniculata), Fm (F. crenata-S. nipponica) and Th (Thujopsis dolabrata-S.paniculata). In each forest, samples were collected from five kinds of materials, namely, M1 (bark), M2 (moss), M3 (fallen plant materials such as twigs and cones), S1 (0-5 cm soil layer), and S2 (5-10 cm soil layer), from each plot Species of orbatid mites were extracted with a modified Tullgren apparatus and respectively numbered 47, 61, 57, 49, 52 and 45 in the Gr, Gm, Gs, Th, Fs and Fm forest samples. It was found that each of the strata contained peculiar fauna, and the large number of individuals as well as species of orbatid mites in moss stratum was comparable to that observed in soil strate. From the values of C_λ, the five strata of each forest were grouped into the folowing : one group in Fs, three groups (M1, M2-S1, M3-S2) in Fm, three groups (M1, M2, M3-S1-S2) in Th, and four groups (M1, M2, M3, S1-S2) in Gm, Gr and Gs.