Lumbricus terrestris abundance in grasslands on sandy soils in relation to soil texture, hydrology and earthworm community

Abstract

Deep-burrowing (anecic) earthworm Lumbricus terrestris contributes to the crucial ecosystem service of water regulation. Their deep, vertical burrows facilitate water flow and deeper rooting, the former supporting the prevention of flooding and waterlogging, the latter improving drought tolerance. In Europe, these earthworms occur in agricultural grasslands on various soil types. However, their distribution pattern can be very heterogeneous. There is no conclusive set of soil biotic or abiotic factors that determines whether L. terrestris occurs or not. Through a better understanding of the L. terrestris distribution patterns we hope to gain more insight into their potential for climate adaptive water regulation.We executed a field inventory (n = 62) to assess the relationship between L. terrestris population density in grassland on sandy soils and soil silt content (loaminess), gley depth, epigeic earthworm population density and grassland age.We found positive correlations between soil silt concentrations and L. terrestris population densities. Gley depth slightly correlated with population density when presented in a model with silt concentration as a predictor. Presence and population density of L. terrestris correlated negatively with L. rubellus abundance. The number of years without mechanical soil disturbance and L. terrestris population density were not significantly related. Unexpectedly, we found L. terrestris in some very sandy soils. Our data was fitted into an existing predictive model based on land use and texture (by Lindahl et al., 2009), yielding 63% accuracy. Overall, this correlative study provides further insights into L. terrestris habitat selection, which helps us understand the species’ potential for water regulation in the widespread grassland agro-ecosystems.