A critical review of the microcosm method in soil animal ecology

Abstract

The microcosm method is widely used in research on soil animal ecology because it allows for controlled manipulations of fauna, climate, and soil properties. However, differences in biotic and abiotic conditions between the microcosm and the natural soil ecosystem it is intended to represent may bias the experimental results. On the basis of literature, potential influences of the following factors were discussed: (1) Microcosm volume and duration of the incubation period. (2) Preparation of the microcosm substrate, with emphasis on the choice between homogenised substrate and intact soil cores. (3) Incubation conditions (moisture, temperature and drainage). (4) Biotic diversity in the microcosm soil, with emphasis on (a) the general problem of low biodiversity in microcosms, (b) the unnatural situation in microcosms without plants, (c) differences in microflora composition between “faunal” and “non-faunal” treatments, and (d) relative densities of the organisms present. Possible ways of dealing with a few of these problems were also discussed.

Keywords

• Experimental design
• soil fauna
• manipulation
• abiotic factors