On the earthworm fauna (Oligochaeta: Lumbricidae), in particular the distribution of Proctodrilus, in the floodplains of the chernozem and gray-brown podzolic soil areas on both sides of the Ore Mts.

In a study of mineral soils in floodplains, shallow depressions, and dry valley heads of the Saale-Elster plateau in eastern Germany and along the lower Eger/Ohře river in Czechia, sixteen earthworm species were found. On the basis of these findings, areas of gray-brown podzolic soils can be differentiated from chernozem areas mainly by the occurrence in the former of the two species Proctodrilus antipai and P. tuberculatus. In a section of one floodplain in the gray-brown podzolic soil area, the distribution of these two earthworm species shows a vicariance situation, such that P. antipai is restricted to the outer edges of the floodplain while P. tuberculatus inhabits the parts close to the river. In the chernozem areas, on the other hand, P. antipai is the only one of the two species to occur, and is also found in those areas close to the river. P. tuberculatus disappears in the transitional zone between a floodplain where it occurs and a chernozem floodplain. The distribution of P. antipai ends where a floodplain inhabited by it graduates into one belonging to a large river with a high rate of flow. On the stretch of the Elbe near Mlékojedy, where the position of the confluence with the Ohře has migrated over time, the vicariant distribution of the two species within the soil profile was noted. Here P. antipai is found in the uppermost soil layer, while P. tuberculatus lives in the lower-lying mineral soil at the same location. This ecological vicariance appears to represent different stages of clay translocation in flood loam. The results show that P. tuberculatus is dependent on such clay translocation or lessivage, and where this soil-profile-influencing process cannot take place the species does not occur. Examples would be oligotrophic acid montane brown forest soils, eutrophic brown forest soils, and chernozems, as well as the floodplain soils derived from all thre