Decomposition of mediterranean leaf litters by Nicodrilus meridionalis (Lumbricidae) in laboratory and field experiments

The decomposition and palatability of forest leaf litters by an earthworm and soil micro-organisms were measured in laboratory and field conditions. The palatability of fresh and composted mediterranean leaf litters (Quercus petraea L. Q. ilex L.; Castanea sativa Mill and Fagus sylvatica L.) for Nicodrilus meridionalis was studied in the laboratory for 31 d with a technique based on the CO, released by different microcosms [soil (S), soil + litter (SL), soil + earthworm (SE); soil + earthworm + litter (SEL)]. The composting of the litters increased their palatability and enhanced earthworm biomass (by 3.5-14.9% depending on the litter). In contrast feeding fresh litters resulted in a loss of earthworm biomass (by 13.2 and 14.2% for F. sylvatica and Q. ilex, respectively) and a small increase in earthworm biomass for C sativa and Q. petraea (by 10.6 and 2.8%). The earthworm biomass was highly correlated with leaf litter quality and particularly, litter N. The decomposition rates of these leaf litters in microcosms and in the field were highly correlated. Our studies may provide a model for a quick estimate of the decomposability and palatability of different kinds of leaf litters for earthworms. (C) 2001 Elsevier Science Ltd. All rights reserved.