Succession of earthworm populations in abandoned fields

Abstract

Earthworm populations of four successional stages of a secondary successional sere in abandoned arable fields were studied in South Bohemia, Czechoslovakia. The successional stages were: (1) an arable field permanently cropped, (2) a juvenile fallow uncultivated from the beginning of this study, (3) a 10 yr old fallow in a later stabilized stage of succession, and (4) a 60–70 yr old fallow regarded as a sub-climax stage of succession. In the initial stages of succession (0–2 yr), very low earthworm populations were found inhabiting the abandoned field (3.6–12.2 ind m −2). Rapid development of an earthworm community started in the third year of succession owing increases in numbers of two “r” type species, Dendrobaena octaedra and Lumbricus rubellus. In the fourth year already the earthworm density (128.0–263.8 ind m −2) reached almost the same value as in the 10 yr old fallow where, however, higher populations of several endogeic species were observed. In sub-climax, a very specific earthworm community was found, highly dominated by the epigeic species, Dendrobaena vejdovskyi. During the course of succession, the proportion of earthworms in the upper soil layer increased and their horizontal distribution became more uneven. The number of earthworm species did not increase, but community structure changed markedly with the increasing age of the succession.