Enchytraeids (microannelids) mainly comprise the enchytraeids (potworms) and also a few other soil-dwelling annelid species (terrestrial polychaetes, tubificids and naidids). With a body diameter of about 0.2-2 mm, microannelids belong to the mesofauna. About 700 species of Enchytraeidae have been described worldwide. In Europe 200-250 species are presently known. Microannelids are sapro-phytophagous soil organisms, feeding on dead organic material colonized by fungi and bacteria, thus accelerating the decomposition of organic substrates. Furthermore, larger enchytraeid species contribute to the formation of soil aggregates and the mixing of soil by their burrowing activity and the transport of material, although at a scale different from that of earthworms.
Knowledge on the autecology of species occurring in Germany has been documented in form of indicator values referring to soil reaction and soil moisture. Updated identification guides are available. Collecting enchytraeids is comparatively easy due to a standardized methodology (ISO), but the number of samples that can be taken simultaneously is limited due to the necessity of identifying specimens alive. Identification to species level requires expert knowledge.