Genetic diversity of Aporrectodea caliginosa from agricultural sites in Northeast Brandenburg, Germany

SummaryIntraspecific genetic variability of the ubiquitous earthworm species Aporrectodea caliginosa (Savigny) was determined, annually for a period of 3 years, along a 151 km transect that traversed a landscape in northeastern Brandenburg, Germany. A. caliginosa was found wherever earthworms were present at agricultural sites. The effect of earthworm species richness on intraspecific variability of A. caliginosa was examined. Intraspecific genetic variability of A. caliginosa was analysed using random amplified polymorphic DNA (RAPD) PCR. Forty-five genotypes were detected in 482 adults collected from 50 agricultural sites. Inter-annual temporal variability in genotypes detected was small (20% variation). The distribution of A. caliginosa genotypes was not related to soil properties and glacial topographic features (e.g., moraines, outwash and glacial valleys). Intraspecific diversity of A. caliginosa and the abundance of A. caliginosa genotypes were significantly influenced by earthworm species richness.Results from the first sampling year were used to develop a model that described intra- and interspecific interactions. The data of the following 2 years were then used to validate the model. Changes in intraspecific diversity of A. caliginosa populations resulted in a genetically different population structure due to high competition or utilization of niches, which might coincide with functional differences.