Relation between (Annelida: Oligochaeta) species abundance and physical and chemical variables of a typical pampean soil

摘要

Sampling of earthworms was carried out in a 250 ha field encompassing 14 soil phases belonging to the argiudol type soil. The relation between earthworm species composition and 13 physicochemical parameters was studied. The most important accounting for the presence and abundance of the dfferent endogeic mesohumic earthworms species were pH, soil organic content, assimilable phosphorus, nitrogen, and electric resistance of the paste. Octolasion and Microscolex were the most restricted to high contents of phosphorus and organic matter genera. All species found in the area are common in environments subjected to agricultural disturbance. Aporrectodea caliginosa seems to be the pioneer species. All the earthworms identified in this study were exotic species except Microscolex dubius