Die Regenwurmfauna (Oligochaeta: Lumbricidae) der Aue der Gro?en Kokel als Abh?ngige der B?den im Flusseinzugsgebiet und der Auengradienten

摘要

In five floodplain transects along the course of the river Tarnava Mare in Rumania, 17 earthworm species were counted. The species spectrum of the earthworm fauna of the studied floodplains is dependent on the provenance of the floodplain sediments. On the basis of this provenance, the fauna of three groups of soil localities on the floodplain are differentiated: in the upper reaches of the river, the fauna of the floodplain soils derived from brown forest soils and podzolic soils (near Sub Cetate); on the eastern side of the middle reaches, the fauna of the soils mainly derived from gray-brown podzolic soils (near Porumbenii Mari, Hoghilag); and on the western side of the middle reaches and the lower reaches, the fauna of the soils principally derived from planosols (near Alma, Valea Lung?). Proctodrilus tuberculatus occurs in the floodplain sediments predominantly derived from the gray-brown podzolic soils, and in those parts of the floodplain derived from planosols P. opisthoductus and Aporrectodea georgii are found. Ap. georgii and Allolobophora leoni are mostly mutually exclusive in the floodplain transect, were they are apparently indicator species of sediment deposition close to the river and/or the effect of high water on the soil chemistry. P. tuberculatus and P. opisthoductus occur as vicarious species in the soil profile of the area where their distribution overlaps. Three soil factors that are significant in determining earthworm distribution are emphasized: lessivage, or translocation of clay; the pervection of colloidal organic matter (humus) into the soil, and the texture of the soil layers resulting from sedimentation. An additional record of the new species P. thaleri is given.