Earthworm activity as a cause of splash erosion in a Luxembourg forest

In a mixed oak—beech forest in the Keuper region of Luxembourg, large parts of the forest floor are free of litter in the spring and summer months. At these sites splash erosion and erosion by overland flow can take place. Of the causes for the origin of the bare soil surface in this forest, leaf litter breakdown by earthworms, especially Lumbricus terrestris (L), is the most important. This earthworm collects leaves from the surface and pulls them into its hole. An investigation of the variables that determine the presence of earthworms and the growth of the litter-free area was carried out in 1978 and 1979.Statistical analysis of the data showed that the food-supply for Lumbricus terrestris was the most important factor in determining the pattern of bare soil exposed on the floor. The presence of hawthorn (Crataegus Laevigata) and absence of beech (Fagus sylvatica) have a positive influence on the presence of Lumbricus terrestris and the yearly maximum of bare soil surface.