Earthworm populations of Roosevelt Avenue (Brussels, Belgium): composition, density and biomass

Earthworms were sampled (electric octet method) in the lawn islets of the 2.5 km long Roosevelt avenue (city of Brussels, Belgium). From a preliminary sampling a total of nine species (five to eight per islet) were found of which four (Aporrectodea caliginosa, A. longa, A. rosea and Lumbricus rubellus) were present in all the islets. No insularity effect could be found. A full year sampling was then performed in five selected islets, revealing total density between 89 and 253 individuals/m(2) and biomass between 49 and 153 g/m(2) (yearly averages). Biomass (but not density) correlated best with silt and pH.