Use of enclosed model ecosystems in soil ecology: a bias towards laboratory research

Enclosed model ecosystems, or microcosms, have become a major research tool in soil ecology. Due to the speed, statistical power and mechanistic insights attainable with laboratory-based microcosm experiments, these have added considerably to our ecological knowledge. However, soil ecologists agree that, due to problems of scale and artificiality, microcosm research should be carried out in the context of appropriately scaled field model ecosystems (e.g. mesocosms). This paper aims at clarifying the terminology of enclosed model ecosystems as well as determining and discussing the frequency with which laboratory and field model ecosystems are used in current soil-ecological research. Among 92 model ecosystem studies published from 1993 to 1998 in soil biological journals, only 19 were performed in the field. Laboratory microcosms are, on average, significantly smaller and experiment duration is significantly shorter than in field model ecosystem studies. They are easier to maintain and allow for a larger number of experiments in a unit of time. We argue that the bias towards laboratory research is mainly caused by the growing demand for publications with high-impact ratings in an increasingly competitive scientific world and by the fact that an increasing emphasis is being placed on subjects where research can be carried out very quickly.