Here we summarize the information on test species, respec-tive group of organisms, known role in the food web/function and assumed/known interactions. Information on the life form of the organisms is based on Hopkin (1997) and Lokke and Van Gestel (1998). As can be seen from Table 1, the types of interactions that may occur between collembolans are numerous, e.g. com-petition, mutualism, neutralism or amensalism (Hopkin, 1997). Predation was included via the mites, which prey on collembolans and enchytraeids (Krogh, 1995). There are some functions less clear, e.g. we know that collembolans can be decomposers to a lesser extent (more important in acidic fields where few earthworms are present) or that some enchytraeid species may feed on fun-gal hyphae as a relevant substrate but it is not entirely understood if they feed on microorganisms (Lokke and Van Gestel, 1998).