Inventory of the abundance of earthworm Lumbricus terrestris in grasslands on sandy soil

The deep, vertical burrows of anecic earthworm Lumbricus terrestris contribute to the ecosystem service of water regulation in grasslands. They facilitate water flow and deeper rooting, thereby supporting the prevention of flooding and improving drought tolerance. In Europe, these earthworms occur in agricultural grasslands on various soil types. However, their distribution pattern is heterogeneous and not well-understood. Through characterisation of L. terrestris distribution patterns, we aim to grasp their potential for climate adaptive water regulation. In a field inventory (n=62) we assessed the relationship between L. terrestris population density in grassland on sandy soils and: soil silt concentration; epigeic earthworm population density; and grassland age. Soil silt concentrations and L. terrestris population densities correlated positively. Population density of L. terrestris correlated negatively with L. rubellus abundance. Population density of L. terrestris was not significantly related to grassland age. Unexpectedly, we found L. terrestris in some very sandy soils. Our data were fitted into an existing predictive model, yielding 63% accuracy.